Supersonic Expansion of the Bipolar H ii Region Sh2-106: A 3500 Year Old Explosion?

Multi-epoch narrowband Hubble Space Telescope images of the bipolar H ii region Sh2-106 reveal highly supersonic nebular proper motions that increase with projected distance from the massive young stellar object S106 IR, reaching over ∼30 mas yr−1 (∼150 km s−1 at D = 1.09 kpc) at a projected separation of ∼1.′4 (0.44 pc) from S106 IR. We propose that S106 IR experienced a ∼1047 erg explosion ∼3500 yr ago. The explosion may be the result of a major accretion burst or a recent encounter with another star, or a consequence of the interaction of a companion with the bloated photosphere of S106 IR as it grew from ∼10 through ∼15 M ⊙ at a high accretion rate. Near-IR images reveal fingers of H2 emission pointing away from S106 IR and an asymmetric photon-dominated region surrounding the ionized nebula. Radio continuum and Brγ emission reveal a C-shaped bend in the plasma, indicating either the motion of S106 IR toward the east, or the deflection of plasma toward the west by the surrounding cloud. The H ii region bends around a ∼1′ diameter dark bay west of S106 IR that may be shielded from direct illumination by a dense molecular clump. Herbig–Haro and Molecular Hydrogen Objects tracing outflows powered by stars in the Sh2-106 protocluster such as the Class 0 source S106 FIR are discussed.

Lessons Learned from the Studies of Roots Shaded from Direct Root Illumination

The root is the below-ground organ of a plant, and it has evolved multiple signaling pathways that allow adaptation of architecture, growth rate, and direction to an ever-changing environment. Roots grow along the gravitropic vector towards beneficial areas in the soil to provide the plant with proper nutrients to ensure its survival and productivity. In addition, roots have developed escape mechanisms to avoid adverse environments, which include direct illumination. Standard laboratory growth conditions for basic research of plant development and stress adaptation include growing seedlings in Petri dishes on medium with roots exposed to light. Several studies have shown that direct illumination of roots alters their morphology, cellular and biochemical responses, which results in reduced nutrient uptake and adaptability upon additive stress stimuli. In this review, we summarize recent methods that allow the study of shaded roots under controlled laboratory conditions and discuss the observed changes in the results depending on the root illumination status.

A FASCINATING SYNTHESIS OF SCIENCE, THEOLOGY, AND SPIRITUALITY: ST. GREGORY PALAMAS

As a prominent Church father, mystical theologian and incisive polemicist, St. Gregory Palamas has realized a «Summa Theologica» of his epoch, but one that has surpassed not only the thinking of contemporaries, but remained, to this day, a synthesis of philosophical and theological knowledge, at least for the Eastern Christianity. He pointed out with clarity the independence of theology from philosophy or from any other field of research. One of the most important instruments with a view to knowing God is prayer and Palamas began to write under the pressure of defending the hesychastic method of prayer. He proves that true communion with God was possible through sanctification and that God's vision through prayer was a sign of this spiritual communion. In Palamas' very coherent theological thinking, Christology corresponds to his anthropology, and both to his mysticism. St. Gregory strongly depreciated the value of intellectual effort, maintaining the primacy of direct illumination over scientific reasoning. Thus, prayer and asceticism engender love, which leads to illumination by God and participation in the divine life. He tries to make sense of mystical experience in the scientific and philosophical language of his day. Paradoxically, almost every attempt arrives at establishing that the spiritual cannot be grasped by man's natural intellectual capacity, nor expressed in philosophical language. But the spiritual man can be the partaker of this experience through the experience of grace, as divine uncreated energy, the true "face" of God accessible to human contemplation. The Archbishop of Thessaloniki, who realized a synthesis of Science, Theology, and Spirituality outlines the relation between them as follows: Science explores the world and leads to technological inventions; Theology interprets reality within the Christian framework, evidencing the glory of God as reflected throughout his creation; and Spirituality is the privileged path toward personal transformation. The debate about Palamism is likely to continue for some time. His version of theosis (deification) was enshrined in Orthodox teaching as a result of his canonization, but among the intellectuals for whom it was intended it remained controversial, despite its grandeur.

ShadingNet: Image Intrinsics by Fine-Grained Shading Decomposition

In general, intrinsic image decomposition algorithms interpret shading as one unified component including all photometric effects. As shading transitions are generally smoother than reflectance (albedo) changes, these methods may fail in distinguishing strong photometric effects from reflectance variations. Therefore, in this paper, we propose to decompose the shading component into direct (illumination) and indirect shading (ambient light and shadows) subcomponents. The aim is to distinguish strong photometric effects from reflectance variations. An end-to-end deep convolutional neural network (ShadingNet) is proposed that operates in a fine-to-coarse manner with a specialized fusion and refinement unit exploiting the fine-grained shading model. It is designed to learn specific reflectance cues separated from specific photometric effects to analyze the disentanglement capability. A large-scale dataset of scene-level synthetic images of outdoor natural environments is provided with fine-grained intrinsic image ground-truths. Large scale experiments show that our approach using fine-grained shading decompositions outperforms state-of-the-art algorithms utilizing unified shading on NED, MPI Sintel, GTA V, IIW, MIT Intrinsic Images, 3DRMS and SRD datasets.

Thermally driven disc winds as a mechanism for X-ray irradiation heating in black hole X-ray binaries: the case study of GX339–4

ABSTRACT X-ray irradiation heating of accretion discs in black hole X-ray binaries (BHXBs) plays a key role in regulating their outburst cycles. However, despite decades of theoretical and observational efforts, the physical mechanism(s) responsible for irradiating these discs remains largely unknown. We have built an observation-based methodology to estimate the strength of irradiation of BHXB discs by combining multiwavelength X-ray and optical/infrared (OIR) data throughout transient outbursts. We apply this to ∼15 yr of activity in the Galactic BHXB GX339–4. Our findings suggest that the irradiation heating required by the optical data is large in this system. Direct illumination of the outer disc does not produce sufficient irradiation, but this should also produce a thermal-radiative wind which adds to the irradiation heating by scattering flux down on to the disc. However, analytic estimates of X-ray illumination from scattering in the wind are still not sufficient to produce the observed heating, even in combination with direct illumination. Either the analytic thermal-radiative wind models are underestimating the effect of the wind, or there are additional scattering mechanisms at work, such as magnetically driven outflows, acting to increase the OIR flux. While wind-driven irradiation is likely a common feature among long-period BHXBs, fully understanding the driving mechanism(s) behind such a wind will require radiation hydrodynamic simulations.