UNKNOWN SEAL OF EMPEROR JUSTIN I (518-527) FROM SERDICA

The paper examines a seal of Emperor Justin I (518-527). It has the following description: Obverse: Beardless bust with a nimbus of Emperor Justin I, opposite, with a helmet and chlamys. Around the image an inscription in clockwise direction: N IVSТI NVSPPAVG = D(ominus) n(oster Justinus p(er)petus Aug(ustus) Reverse: Victoria standing across with a wreath in each hand, in the bottom left field a small So far there is not known bulla of this ruler from Bulgaria and because of that some questions arise when identifying the specimen from Serdica. The inscription on the newly discovered seal showed that the bulla belonged to Justin, but it is not clear if it is Justin I (518-527) or Justin II (565-578). The image on the obverse differs from the known images of Justin I and Justin II. It is smaller and occupies part of the nucleus, while in the published so far the size of the bullotirium is larger than the nucleus itself. The inscription of the copy from Serdica is clearly legible, but the letters and the image are small, which distinguishes this seal from the known so far. The difference is obvious also in the reverse, in which Victoria does not follow the model of the image from the molybdenums of Justinian I and Justin II, but her image is close to that of the seals of Anastasius I, and even could be said that it completely copies it. The characteristics of the seal, its inscription and images are different from the ones of the copies of Justin II, which is a serious reason to attribute it to the time of Emperor Justin I, which makes it currently unique of this type. Other evidence of life in Serdica from the time of Emperor Justin I (518 - 527) are the coins discovered. In Serdica the most numerous are the coins of 40 nummi, followed by those of 20 nummi, which are almost two times less than the large denomination. The number of the specimens of 10 and 5 nummi is equal, but is less than the number of the large denominations. As mints, the coins from Constantinople predominated, followed by coins from Nicomedia, Antioch and Cyzicus. Among the regular coins were found two imitations of folles of Justin I, which imitate the production of the mint of Constantinople from this period. These coins, found together with the official ones used in the Byzantine state, show that they were accepted by the financial authorities as a regular payment tool. Two gold coins of Justin I are discovered in Serdica I - a solidus found at the eastern fortress wall and a tremis from the excavations at the northeastern tower. The new seal of Emperor Justin I presented in the article and the coins discovered by this ruler in Serdica show the significant role of the city during this period.

Divergence and Curl of COVID19 Spreading in the Lower Peninsula of Michigan

This paper explores the COVID19 transmission pattern and circulation dynamics in the Euclidean space at the lower peninsula of Michigan by using the divergence and curl concept in vector field. The COVID19 transmission volume flux can be calculated for each county by using vector divergence. The results shows Wayne county had the highest divergence (162660), the Kent county had the second highest divergence (152540), and the Saginaw county had the third highest divergence (103240), the divergence is positive which means the COVID19 virus was transmitted from these counties to other places. The results also shows Monroe county had the lowest divergence (-187843), the Allegan county had the second lowest number in divergence (-90824), the divergence is negative which means the COVID19 virus was transmitted from other places to these counties. The circulation of the virus is also calculated by using vector curl. The positive curl means that the virus has circulated in a counter-clockwise direction, and the negative curl means the virus has circulated in a clockwise direction. The divergence is an operator of the COVID19 transmission vector field, which produces a scalar field giving the quantity of the transmission vector field’s source at each location. The COVID19 spreading volume density of the outward flux of transmission field is represented by divergence around a given location. The curl is an operator of the COVID19 transmission field, which describes the circulation of a transmission vector field. The curl at a location in COVID19 transmission field is represented by a vector whose length and direction denote the magnitude and axis of the maximum circulation. The curl of a transmission field is formally defined as the circulation density at each location of COVID19 transmission field.

Curious behaviour of spinning coffee cups and other spinning objects

If an empty coffee cup is spun on a horizontal surface about a vertical axis in an anti-clockwise direction, then the whole cup rotates slowly backwards, in a clockwise direction, about a vertical axis located outside the cup. Clues to this curious behaviour are presented by comparing it with other spinning objects.

Stellar Spins in the Pleiades, Praesepe, and M35 Open Clusters

We analyze spectroscopic and photometric data to determine the projected inclinations of stars in three open clusters: the Pleiades, Praesepe, and M35. We determine the sin i values of 42, 35, and 67 stars in each cluster, respectively, and from their distributions we find that isotropic spins and moderate alignment are both consistent with the Pleiades and Praesepe data. While it is difficult to distinguish between these scenarios for a single cluster, an ensemble of such distributions may facilitate a distinction. The M35 inclination distribution is most consistent with a superposition of isotropic and anisotropic spins, the source of which could be systematic error or a physical grouping of aligned stars. We also study internal cluster kinematics using radial velocities and proper motions. Our kinematics analysis reveals significant plane-of-sky rotation in Praesepe, with a mean velocity of 0.132 ± 0.022 km s−1 in a clockwise direction.

A modified multiplexed vortex helico-conical petal-like zone plate

A modified multiplexed vortex helico-conical petal-like zone plate (MMVHPZP) is proposed to generate a polygon-like beam or light-arm beam with an adjustable opening. The MMVHPZP consists of the modified helico-conical petal-like zone plate (MHPZP) with the topological charge l and exponent n, and the multiplexed vortex spiral phase plate (MVSPP) with the inner topological charge l1 and outer topological charge l2. Moreover, when l1 is equal or unequal to l2, the MMVHPZP has the adjustable polygon-like beam or light-arm beam, respectively. In addition, when n is small or large, the number of arms is equal to the absolute difference between l1 and l2 or the sum of one and the absolute difference between l1 and l2, respectively. Furthermore, for the different l1 or l2, the opening is constant. With the increase of the n or l, the opening is larger. When l1 is greater or less than l2, the rotation direction of arms is the anticlockwise or clockwise direction, respectively.

Factors influencing the removal torque of palatal implant used for orthodontic anchorage

Background A non-invasive method has recently been introduced to remove osseo-integrated palatal implants by using the implantation ratchet which is designed to screw in or unscrew the implants. Although a proof of concept has been published, the torque involved to successfully explant have not been investigated so far. The aim of this study was to assess the removal torque required to explant osseo-integrated and orthodontically utilized palatal implants, and to identify potentially influencing variables. Materials and method Thirty-one consecutive patients (15 females, 16 males; mean age 24.1 ±7.4 years) with fully osseo-integrated and previously orthodontically loaded palatal implants (Orthosystem®: diameter 4.1mm/length 4.2mm/sandblasted with large grits (SLA) surface) were randomly assigned to either clockwise or counter-clockwise non-invasive explantation. The respective explantation tool with an electric torque control was placed on the abutment connection of the implant and secured by an occlusal screw. The primary outcome studied was maximal removal torque (MRT) needed to detach the implant from its socket which was recorded individually together with other potentially influencing secondary outcomes (gender, age, orthodontic loading time, use of local anaesthetics). Student’s t-test was used to contrast MRT difference for the gender, type of suprastructure, use of local anaesthetics, and rotational direction. Spearman correlations was used to investigate associations between MRT and patient’s age or duration loading time. Results Average MRT (148.6 ± 63.2N/cm) using ratchet as a non-invasive removal method of palatal implant was considered safe. The triangular head fractured of palatal implant at a torque level of 300.1 Ncm. Significantly higher explantation were recorded for male patients compared to female patients (182.0 ± 63.0 Ncm vs 112.8 ± 40.8 Ncm; P=0.001). On the other side, the mean removal torque for palatal removal in clockwise direction was non-significantly different (158.3 ± 58.6 Ncm) compared to counter-clockwise direction (139.4 ± 67.9 Ncm). Neither patient’s age (p=0.324) nor loading time (p=0.214) were significantly correlated with removal torque values. Conclusions Pertinent literature on this subject is practically non-existent, as orthodontics is presumably the only discipline where implant removal represents a treatment success. Mean MRT for successful palatal implant removal was 148.6±63.2Ncm, but a large spectrum was observed (minimum 31.5Ncm, maximum 272.8Ncm). This obvious heterogeneity underlines the importance to investigate possible influencing factors. The safe and simple non-invasive method for palatal implant removal necessitates moderate, but not high torque MRTs, independently of the torque direction. The necessary MRT seems clearly influenced by gender, but less so by patient’s age or loading time.

Trapping and rotation of microparticles using a metasurface exciting by linearly polarized beam

We numerically demonstrate trapping and rotation of particles using a metasurface formed by arranging nanocavities as a right-handed Archimedes’ spiral. Excited by a 90° linearly polarized beam, a focused surface plasmon polariton (SPP) field is formed at the center of the spiral, and the particle can be trapped by the field. While excited by −45° linearly polarized beams, a vortex SPP field carrying orbital angular momentum is formed, and the particles can be trapped and rotated in the clockwise direction at the vortex field.

DOSIMETRIC COMPARISON OF VMAT AND 3D CONFORMAL RADIOTHERAPY IN PREOPERATIVE RECTAL CANCER

The standard procedure in treating rectum cancer is surgical intervention, but presurgical chemotherapy and radiotherapy lead to a lower rate of localized recidives. Our study compared the results obtained by two techniques of radiation treatment planning (RTP) in radiotherapy, which patients received in the preoperative course of rectum cancer treatment, Volumetric Modulated Arc Therapy (VMAT) and field-in-field three-dimensional conformal radiotherapy (FIF 3D-CRT). We analyzed better coverage of the planning target volume (PTV) and better protection of organs from risk (OAR): bladder, bowel, left femoral head, and right femoral head results and monitor unit (MU). Also, we analyzed the target volume coverage indicators included homogeneity index (HI), and conformity index (CI). Selected five patients were treated in University Clinical Center Kragujevac during 2020. The two types of techniques for making radiotherapy plans, mentioned above, were designed for each patient using the same CT scans. All plans were done on the treatment planning system ECLIPSE- Version 15.6 (Varian). The prescribed dose for all patients was 50 Gy in 25 fractions. The first arc was planned in the clockwise direction and the second in the counter clockwise direction. FIF 3D-CRT plans were obtained by using fields from four different directions with the same isocenter. It was obtained that VMAT plans, compared to the FIF 3D-CRT, achieved better coverage of the PTV (D95%), better heterogeneity, and conformity. Protection for OAR such as the bladder, femoral heads, and small bowel is much better than that given by FIF 3D-CRT plans. However, the number of MU calculated by FIF 3D-CRT is almost twice lower compared to VMAT.

Honoring the King of Mountains

This chapter explores the ritualized ways in which the mountain is honored, specifically its circumambulation (parikrama) and devotional worship (puja). Pious pilgrims have been circumambulating Mount Govardhan for centuries; today, their numbers seem to be rising steadily. Although no official statistical information is available, residents of the five towns around the mountain report swelling crowds of visitors coming to circumambulate the sacred mountain. The routine parikrama draws thousands of pilgrims daily, and these numbers surge considerably on special days. The customary way of performing the circumambulation of Mount Govardhan consists of walking around the hill reverentially in a clockwise direction. All pilgrims are to fix their hearts and minds on this mountain form of Krishna and commune with it visually through sight (darshan) and physically with touch (sparshan).

Enodicalix (Diploporita, Aristocystitidae): A new echinoderm genus from the Middle Ordovician of Spain

Restudy of an Ordovician diploporite specimen from the Middle Ordovician of central Spain reveals that the species ‘Calix’ inornatus MELÉNDEZ has four ambulacra, each with two equal facets, an oval hydropore and a smooth thecal surface. In contrast, the type species of Calix has four ambulacra, each with four facets added in a clockwise direction during growth, a trilobed hydropore, and a theca with spiny plates. Other aristocystitid genera with four ambulacra have one facet per ambulacrum. ‘Calix’ inornatus differs from all other aristocystitid genera and warrants a new generic name, for which we propose Enodicalix.