Evaluation of Groundwater Resource in Huaian Region of Jiangsu Province, China

Abstract

An asymptotically flat hairy black hole (HBH) can exhibit distinct characteristics when compared to the Schwarzschild black hole, due to the evasion of no-hair theorem by minimally coupling the Einstein gravity with a scalar potential which possesses asymmetric vacua, i.e, a false vacuum (ϕ = 0) and a true vacuum (ϕ = ϕ1). In this paper, we investigate the geodesic motion of both massive test particles and photons in the vicinity of HBH with ϕ1 = 0.5 and ϕ1 = 1.0 by analyzing their effective potentials derived from the geodesic equation. By fixing ϕ1, the effective potential of a massive test particle increases monotonically when its angular momentum L is very small. When L increases to a critical value, the effective potential possesses an inflection point which is known as the innermost stable of circular orbit (ISCO), where the test particle can still remain stable in a circular orbit with a minimal radius without being absorbed by the HBH or fleeing to infinity. Beyond the critical value of L, the effective potential possesses a local minimum and a local maximum, indicating the existence of unstable and stable circular orbits, respectively. Moreover, the HBH possesses an unstable photon sphere but its location slightly deviates from the Schwarzschild black hole. The trajectories of null geodesics in the vicinity of HBH can also be classified into three types, which are the direct, lensing and photon sphere, based on the deflection angle of light, but the values of impact parameters can vary significantly than the Schwarzschild black hole.

Three Cambrian fossils assembled into an extinct body plan of cnidarian affinity

“…sinica Represents a Stem-Group Cnidarian. X. sinica has been alternatively interpreted as a crown-group cnidarian (16,(19)(20)(21)(22), a ctenophore (23,26), a lophophorate (27), or a survivor of vendobionts (28). We have shown here that X. sinica had a relatively simple anatomy with a radial symmetry, a polypoid body, and a blind gut containing septum-like structures.…”

“…The polypoid body shape of X. sinica has led some authors to assume that it might represent an early lineage of crown cnidarians, with previous reconstructions resembling a modern sea anemone (21)(22)(23)(24). However, the feather-like architecture of tentacles described herein is unknown from extant actiniarians or possible Cambrian cnidarian candidates such as Eolympia pediculata (28), Archisaccophyllia kunmingensis (29), Thaumaptilon walcotti (53), Mackenzia costalis (53), and Echmatocrinus brachiatus (54).…”

“…These putative species have been assigned to three different animal groups: hexacorals (16,(19)(20)(21)(22)(23)(24), octocorals (17,25), and hemichordates (18), respectively. However, alternative views suggest that X. sinica was a ctenophore (23, 26), a lophophorate (27), an Ediacaran survivor (28), or a metazoan of unknown affinity (29,30).…”

Evidence for gill slits and a pharynx in Cambrian vetulicolians: implications for the early evolution of deuterostomes

“…In our view, the most compelling observation revolves around the arrangement of the anterior unit and especially the longitudinal grooves, which we propose played a key role. While evidently having the same composition as the rest of the anterior body wall, the grooves appear to have been more flexible [28]. This is particularly evident from the range of configurations that vary from specimens where the groove is effectively closed (Figure 4A) to others where either margin is widely separated (Additional file 1).…”

“…The crux of the problem revolves around the nature of prominent lateral structures, but to date there is neither agreement as to their original configuration nor function. Identifications range from midgut glands [27] to respiratory organs, but in the latter case interpretations are as disparate as a direct comparison to crustacean branchial chambers [12,20,21,28] as against pharyngeal gill slits [13,16,17,24]. Resolution of this divergence of interpretations would be possible if exquisitely preserved material were available that would allow not only a complete anatomical description but one that can be combined with a plausible functional analysis.…”