Renaissance theories of vision

A collection of essays by leading art and architectural historians which examine treatises and works of art produced throughout Europe during the Renaissance in order to understand how artists and writers conceived of processes of vision and perception, and how those conceptions influenced the works of art. Keywords: Renaissance, vision, perception, optics, Plato (Meno, Republic, Symposium, Timaeus), Aristotle (De anima, Metaphysics, Nicomachean Ethics, Physics), Plotinus (Enneads), Saint Augustine (De Civitate Dei), Ibn Sina (Avicenna, Liber canonis), Ibn al-Haytham (Alhazen, De Aspectibus), Ibn Sahl, Marsilio Ficino (De amore, Theologia Platonica), Nicholas of Cusa (On Conjecture, On Learned Ignorance, On the Vision of God), Leon Battista Alberti (De pictura), Gian Paolo Lomazzo (Trattato della pittura), Gregorio Comanini (Il Figino), John Davies (Nosce Teipsum, Orchestra), René Descartes (Optics), Samuel van Hoogstraten, George Berkeley (A New Theory of Vision), Florence, Rome, Venice, England, Austria, Netherlands, Fra Angelico (Annunciation, Lamentation, Lamentation Over the Dead Christ), Donatello (Chellini Madonna, Coronation of the Virgin, Crucifix, Piot Madonna), Leonardo da Vinci (Last Supper, Notebooks, Treatise on Painting, Two Views of the Skull, Uffizi Annunciation, Vitruvian Man), Filippino Lippi (Delphic Sibyl), Giovanni Bellini (Agony in the Garden, Coronation of the Virgin), Raphael (Disputa, Holy Family, Jurisprudence, Madonna di Foligno, Parnassus, School of Athens, Sistine Madonna), Parmigianino (Self Portrait in a Convex Mirror), Titian (Assunta, Salome), Bronzino (Pygmalion and Galatea), Johannes Gumpp (Self Portrait), Rembrandt van Rijn (Bathsheba at Her Bath, Jeremiah Lamenting the Destruction of Jerusalem, The Jewish Bride, Lucretia, The Night Watch, Salome, Self Portrait, The Syndics, Titus, A Woman Bathing), Svetlana Alpers (The Art of Describing, Rembrandt’s Enterprise, The Vexations of Art), Thomas Aquinas (Summa Theologica, Commentary on the Sentences), Roger Bacon, Francesco Barozzi, Celeste Brusati (Artifice and Illusion), Norman Bryson (Looking at the Overlooked, Vision and Painting), Baldessare Castiglione (Libro del cortegiano), catoptrics, dioptrics, extramission, intromission, Benvenuto Cellini (Perseus), Giovanni Chellini, Antonio Correggio (Assumption of the Virgin), Georges Didi-Huberman (Fra Angelico), Samuel Edgerton (The Heritage of Giotto’s Geometry), Euclid (Elements of Geometry, Optica), Kamāl al-Dīn al-Fārisī (The Revision of Optics), Giovan Ambrogio Figino, Fra Bartolommeo, Fra Filippo Lippi (Annunciation), Piero della Francesca (De prospectiva pingendi), Galileo (Sidereus Nuncius), Galleria degli Uffizi, Galleria Doria Pamphili, Lorenzo Ghiberti (Commentaries), Domenico Ghirlandaio (Annunciation), Giles of Viterbo, Giorgione (Adoration of the Shepherds), Herbert Grabes (The Mutable Glass), Anthony Grafton (Leon Battista Alberti), Martin Heidegger (Poetry, Language, Thought), Edmund Husserl, Cristiaan Huygens, Immanuel Kant (Critique of Pure Reason), Martin Kemp (The Science of Art), Johannes Kepler, Alkindi (De Aspectibus), Murray Krieger (Ekphrasis), Diogenes Laertius (On the Lives of Philosophers), John Locke, Andrea Mantegna (Friedsam Madonna, St. Sebastion, Trivulzio Altarpiece), Giambattista Marino (La galeria), Masaccio (Tribute Money, Trinity), Museo San Marco, Narcissus, Neoplatonism, Agrippa von Nettesheim (De occulta philosophia), Erwin Panofsky, Platonic Academy, Pliny the Elder, Proclus (Commentary on the First Book of Euclid’s Elements), Ptolemy, Pythagoras, Peter Paul Rubens (Judith with the Head of Holofernes), William Shakespeare (The Rape of Lucrece, Venus and Adonis), Stanza della Segnatura, Giorgio Vasari (Vite), Vatican, Diego Velázquez (The Spinners), Johannes Vermeer (The Artist in His Studio, Girl with a Pearl Earring, View of Delft), Ernst van de Wetering (Rembrandt), Joost van den Vondel, Erasmus Witelo (Perspectivae), Heinrich Wölfflin (Principles of Art History

Initial surface deformations during impact on a liquid pool

A tiny air bubble can be entrapped at the bottom of a solid sphere that impacts onto a liquid pool. The bubble forms due to the deformation of the liquid surface by a local pressure buildup inside the surrounding gas, as also observed during the impact of a liquid drop on a solid wall. Here we perform a perturbation analysis to quantitatively predict the initial deformations of the free surface of the liquid pool as it is approached by a solid sphere. We study the natural limits where the gas can be treated as a viscous fluid (Stokes flow) or as an inviscid fluid (potential flow). For both cases we derive the spatio-temporal evolution of the pool surface, and recover some of the recently proposed scaling laws for bubble entrapment. When inserting typical experimental values for the impact parameters, we find that the bubble volume is mainly determined by the effect of gas viscosity

Universal mechanism for air entrainment during liquid impact

When a mm-sized liquid drop approaches a deep liquid pool, both the interface of the drop and the pool deform before the drop touches the pool. The build up of air pressure prior to coalescence is responsible for this deformation. Due to this deformation, air can be entrained at the bottom of the drop during the impact. We quantify the amount of entrained air numerically, using the Boundary Integral Method (BIM) for potential flow for the drop and the pool, coupled to viscous lubrication theory for the air film that has to be squeezed out during impact. We compare our results to various experimental data and find excellent agreement for the amount of air that is entrapped during impact onto a pool. Next, the impact of a rigid sphere onto a pool is numerically investigated and the air that is entrapped in this case also matches with available experimental data. In both cases of drop and sphere impact onto a pool the numerical air bubble volume V_b is found to be in agreement with the theoretical scaling V_b/V_{drop/sphere} ~ St^{-4/3}, where St is the Stokes number. This is the same scaling that has been found for drop impact onto a solid surface in previous research. This implies a universal mechanism for air entrainment for these different impact scenarios, which has been suggested in recent experimental work, but is now further elucidated with numerical results

Exosomes released from breast cancer carcinomas stimulate cell movement

For metastasis to occur cells must communicate with to their local environment to initiate growth and invasion. Exosomes have emerged as an important mediator of cell-to-cell signalling through the transfer of molecules such as mRNAs, microRNAs, and proteins between cells. Exosomes have been proposed to act as regulators of cancer progression. Here, we study the effect of exosomes on cell migration, an important step in metastasis. We performed cell migration assays, endocytosis assays, and exosome proteomic profiling on exosomes released from three breast cancer cell lines that model progressive stages of metastasis. Results from these experiments suggest: (1) exosomes promote cell migration and (2) the signal is stronger from exosomes isolated from cells with higher metastatic potentials; (3) exosomes are endocytosed at the same rate regardless of the cell type; (4) exosomes released from cells show differential enrichment of proteins with unique protein signatures of both identity and abundance. We conclude that breast cancer cells of increasing metastatic potential secrete exosomes with distinct protein signatures that proportionally increase cell movement and suggest that released exosomes could play an active role in metastasis

Energy spectrum of turbulent fluctuations in boundary driven reduced magnetohydrodynamics

The nonlinear dynamics of a bundle of magnetic flux ropes driven by stationary fluid motions at their endpoints is studied, by performing numerical simulations of the magnetohydrodynamic (MHD) equations. The development of MHD turbulence is shown, where the system reaches a state that is characterized by the ratio between the Alfven time (the time for incompressible MHD waves to travel along the field lines) and the convective time scale of the driving motions. This ratio of time scales determines the energy spectra and the relaxation toward different regimes ranging from weak to strong turbulence. A connection is made with phenomenological theories for the energy spectra in MHD turbulence.Comment: Published in Physics of Plasma

Pola Pemanfaatan Ruang Bersama pada Rusunawa Jatinegara Barat

Relokasi warga Kampung Pulo ke Rusunawa Jatinegara Barat membuat warga harus beradaptasi dengan lingkungannya, khususnya dalam kegiatan interaksi sosial. Hal ini yang mendasari peneliti untuk melakukan pengamatan mengenai pola pemanfaatan ruang bersama untuk kegiatan interaksi sosial, baik ruang bersama yang direncanakan maupun ruang bersama yang tidak direncanakan. Tujuan dari penelitian ini untuk menilai keberhasilan adaptasi penghuni dalam memenuhi kebutuhannya dalam berinteraksi dan mengetahui faktor yang mempengaruhi pola ruang bersama. Metode pengumpulan data menggunakan “mapping behavior”, yaitu cara untuk menggambarkan perilaku dalam peta, mengidentifikasikan jenis frekuensi perilaku, serta menunjukkan kaitan perilaku dengan wujud perancangan yang spesifik. Karena pola ruang tercipta akibat hubungan timbal Balik antara manusia dengan ruang.Penelitian ini menggunakan teknik analisis deskriptif kualitatif, yaitu menerjemahkan data hasil observasi dan data hasil wawancara ke dalam bentuk uraian yang dapat lebih dimengerti. Penghuni memanfaatkan ruang bersama yang direncanakan dan tidak direncanakan untuk berinteraksi sosial antar penghuni. Pemanfaatan ruang telah menghasilkan sebuah pola-pola ruang bersama yaitu pola dengan intensitas tinggi dan pola dengan intensitas rendah. Ruang bersama dengan intensitas penggunaan tinggi relatif jauh dari hunian dengan frekuensi penggunaan jam-harian. Adapun ruang yang digunakan yaitu selasar lantai hunian, plaza terbuka, area pujasera, taman bermain dan lobby lift

High-power three-port three-phase bidirectional DC-DC converter

This paper proposes a three-port three-phase bidirectional dc-dc converter suitable for high-power applications. The converter combines a slow primary source and a fast storage to power a common load (e.g., an inverter). Since this type of system is gaining popularity in sustainable energy generation systems and electrical vehicles, the proposed topology is of practical interest. The proposed converter consists of three high-frequency inverter stages operating in a six-step mode, and a high-frequency three-port three-phase symmetrical transformer. The converter provides galvanic isolation and supports bidirectional power flow for all the three ports. An arbitrary power flow profile in the system can be achieved by phase shifting the three inverter stages. Thanks to the three-phase structure, the current handling capability of the circuit is larger and the ripple currents at the dc sides are much lower owing to the interleaving effect of the threephase, and thus the VA rating of the filter capacitors is much lower. The operating principle and, in particular, the transformer design which is based on conventionally and coaxially wound structures are presented. Circuit simulation results are included to verify the proposed converter topology and the dual-PI-loop control strategy