Calculation of asymptotic charges at the critical sets of null infinity

The asymptotic structure of null and spatial infinities of asymptotically flat spacetimes plays an essential role in discussing gravitational radiation, gravitational memory effect, and conserved quantities in General Relativity. Bondi, Metzner and Sachs established that the asymptotic symmetry group for asymptotically simple spacetimes is the infinite-dimensional BMS group. Given that null infinity is divided into two sets: past null infinity $\mathscr{I}^{-}$ and future null infinity $\mathscr{I}^{+}$, one can identify two independent symmetry groups: $\text{BMS}^{-}$ at $\mathscr{I}^{-}$ and $\text{BMS}^{+}$ at $\mathscr{I}^{+}$. Associated with these symmetries are the so-called BMS charges. A recent conjecture by Strominger suggests that the generators of $\text{BMS}^{-}$ and $\text{BMS}^{+}$ and their associated charges are related via an antipodal reflection map near spatial infinity. To verify this matching, an analysis of the gravitational field near spatial infinity is required. This task is complicated due to the singular nature of spatial infinity for spacetimes with non-vanishing ADM mass. Different frameworks have been introduced in the literature to address this singularity, e.g., Friedrich's cylinder, Ashtekar-Hansen's hyperboloid and Ashtekar-Romano's asymptote at spatial infinity. This paper reviews the role of Friedrich's formulation of spatial infinity in the investigation of the matching of the spin-2 charges on Minkowski spacetime and in the full GR setting.Comment: 16 pages, 2 Figures (A major change in the structure and content compared to earlier version. The changes are made to agree with the peer reviewed version.

Evaluation of Post-operative Pain after Irrigation Using End-vented NaviTip Tips versus Vibringe Sonic Irrigating System in Teeth with Acute Pulpitis with Apical Periodontitis: A Randomized Clinical Trial

AIM: This clinical study was conducted to evaluate and compare the post-operative pain after the using of two different irrigating techniques: Vibringe sonic irrigating system with end-vented NaviTip and conventional needle with end-vented NaviTip immediate postoperatively and 4, 12, 24, 48, and 72 h and 7 days utilizing a numerical rating scale (NRS). METHODS: Thirty-eight patients with acute pulpitis with apical periodontitis were involved in this study. Root canals were prepared using NiTi ProTaper Universal rotary system then randomized into two equal groups according to the technique used for irrigation Group A, Vibringe sonic irrigating system with end-vented NaviTip and Group B, conventional syringe with end-vented NaviTip® irrigating tip. The needles of irrigation were penetrated 2 mm shorter than the working length. The trial design of this study is a parallel randomized controlled trial. RESULTS: All demographic data, clinical and radiographic findings, and modified NRS scores obtained from patients were statistically analyzed. Results showed that there was no statistically difference between the two groups regarding the demographic data, prevalence of pre-operative pain, after 4 h, 12 h, 24 h, and 48 h and 7 days, while in both groups, there was a statistically significant decrease in pain intensity preoperatively compared with all other time periods. CONCLUSION: There is no statistical significance difference between Vibringe sonic irrigating syringe with endvented needle and conventional syringe with end-vented NaviTip, while in both groups, there was a statistically significant decrease in pain intensity preoperatively compared with all other time periods

The Impact of a Computer Training Program on the Ministry of Education and Higher Education Staff to Improve Computer Skills and Productive Performances

The current study aims at identifying the impact of the training program (International Computer Driving Licence, CDL), which is used to improve skills and productivity performances, on the of Education and Higher Education Ministry staff, the sample consisted of 216 school head teachers and head teachers assistant in east and west directorates in Gaza city. The researchers applied the two study tools, which were the computer skills questionnaire, and training impact measuring questionnaire, to in the staff workplaces, the results have shown the statistically significant differences at level (α= 0.01) for of the post application, That means, the training program has positive and good effect on computer skills enhancement. Moreover, the results also indicate that the staff average of the acquired skills and experiences was higher than the needed percent competence required (80%). The study recommended to work on the different training programmer for the Ministry staff as well as identifying the training needs for each one

Asymptotic charges for spin-1 and spin-2 fields at the critical sets of null infinity

The asymptotic BMS charges of spin-1 and spin-2 fields are studied near spatial infinity. We evaluate the charges at the critical sets where spatial infinity meets null infinity with the aim of finding the relation between the charges at future and past null infinity. To this end, we make use of Friedrich's framework of the cylinder at spatial infinity to obtain asymptotic expansions of the Maxwell and spin-2 fields near spatial infinity which are fully determined in terms of initial data on a Cauchy hypersurface. Expanding the initial data in terms of spin-weighted spherical harmonics, it is shown that only a subset of the initial data, that satisfy certain regularity conditions, gives rise to well-defined charges at the point where future (past) infinity meets spatial infinity. Given such initial data, the charges are shown to be fully expressed of the freely specifiable part of the data. Moreover, it is shown that there exists a natural correspondence between the charges defined at future and past null infinity.Comment: 18 pages, 1 figur

BMS-supertranslation charges at the critical sets of null infinity

For asymptotically flat spacetimes, a conjecture by Strominger states that asymptotic BMS-supertranslations and their associated charges at past null infinity I − can be related to those at future null infinity I + via an antipodal map at spatial infinity i0. We analyze the validity of this conjecture using Friedrich’s formulation of spatial infinity, which gives rise to a regular initial value problem for the conformal field equations at spatial infinity. A central structure in this analysis is the cylinder at spatial infinity I representing a blow-up of the standard spatial infinity point i0 to a 2-sphere. The cylinder I touches past and future null infinities I ± at the critical sets I ± . We show that for a generic class of asymptotically Euclidean and regular initial data, BMS-supertranslation charges are not well-defined at I ± unless the initial data satisfies an extra regularity condition. We also show that given initial data that satisfy the regularity condition, BMS-supertranslation charges at I ± are fully determined by the initial data and that the relation between the charges at I − and those at I + directly follows from our regularity condition

Synthesis of Sulfotyrosine Bearing Peptides and Analogues

Sulfation of tyrosine residues is a post-translational modification that occurs on many secretory as well as transmembrane proteins. This modification is believed to be essential for numerous biological processes. However, one of the factors hindering the study of the significance of sulfotyrosine (sTyr) within a protein is the absence of a general method that enables the synthesis of sTyr peptides in satisfactory yields and purity. A general approach to the synthesis of sTyr-bearing peptides was developed in which the sTyr residue is incorporated into the peptides with the sulfate group protected. For the implementation of this general approach a new protecting group for sulfates, namely, the dichlorovinyl (DCV) group was developed. This was accomplished by conducting a careful analysis of the reaction of a trichloroethyl (TCE)-protected sulfate ester with piperidine and 2-methylpiperidine (2-MP). A unique sulfuryl imidazolium reagent, compound 2.22, was also developed that enabled the ready synthesis of DCV-protected sulfates. This reagent was used to prepare the amino acid building block FmocTyr(SO3DCV)OH (2.23). An alternative and more economical synthesis of FmocTyr(SO3DCV)OH (2.23) was also developed that did not require reagent 2.22. Fmoc-based solid phase peptide synthesis (SPPS) was used to incorporate 2.23 into peptides using 2-MP for Fmoc removal. After cleavage of the peptide from the support, the DCV group was removed by hydrogenolysis to give sTyr peptides in good yield and purity. Using this approach a variety of sTyr peptides were prepared including a tetrasulfated 20-mer corresponding to residues 14-33 in chemokine receptor D6 and a disulfated 35-mer corresponding to residues 8-42 of the N-terminus region of the chemokine receptor DARC and this is the largest multisulfated sTyr–bearing peptide made to date. It was also demonstrated that the incorporation of an important non-hydrolyzable sTyr analog, 4-(sulfonomethyl)phenylalanine (Smp), into peptides can be accomplished in good yield by protecting the sulfonate residue with a TCE group during SPPS. This approach was shown to be superior to the previously reported method where the sulfonate group is unprotected. Finally, a number of sulfotyrosine bearing peptides were synthesized and tested as protein tyrosine phosphatase-1B (PTP1B) inhibitor

BMS-supertranslation charges at the critical sets of null infinity

For asymptotically flat spacetimes, a conjecture by Strominger states that asymptotic BMS-supertranslations and their associated charges at past null infinity $\mathscr{I}^{-}$ can be related to those at future null infinity $\mathscr{I}^{+}$ via an antipodal map at spatial infinity $i^{0}$. We analyse the validity of this conjecture using Friedrich's formulation of spatial infinity, which gives rise to a regular initial value problem for the conformal field equations at spatial infinity. A central structure in this analysis is the cylinder at spatial infinity representing a blow-up of the standard spatial infinity point $i^{0}$ to a 2-sphere. The cylinder touches past and future null infinities $\mathscr{I}^{\pm}$ at the critical sets. We show that for a generic class of asymptotically Euclidean and regular initial data, BMS-supertranslation charges are not well-defined at the critical sets unless the initial data satisfies an extra regularity condition. We also show that given initial data that satisfy the regularity condition, BMS-supertranslation charges at the critical sets are fully determined by the initial data and that the relation between the charges at past null infinity and those at future null infinity directly follows from our regularity condition.Comment: 59 pages, no figure

Evaluation of the Biocompatibility of a Recent Bioceramic Root Canal Sealer (BioRoot™ RCS): In-vivo Study

BACKGROUND: Recently, new calcium silicate bioceramic sealers were introduced to the market. The selection of root canal sealers should not only be based on the different physical parameters but also on local biocompatibility and tissue tolerance. AIM: This study aimed to evaluate and compare the in-vivo biocompatibility of a BioRoot RCS in parallel to MTA Fillapex and AH Plus sealers. METHODS: Polyethylene tubes containing the freshly mixed test materials were implanted in the subcutaneous tissue of 32 Wistar rats. Empty tubes served as negative controls. After 7, 14, 30, and 60 days, the animals were sacrificed, and the implants with surrounding tissues were processed for routine histological analysis. Histological sections were analyzed under light microscopy. The tissue response was determined by the inflammatory cell infiltration intensity and the fibrous capsule thickness. RESULTS: Results revealed a statistically significant decrease of the inflammation intensity by time within each group for all tested sealers and control. A well-defined thin capsule was observed for all tested sealers at 60 days. CONCLUSION: BioRoot RCS exhibited rapid recovery of inflammation similar to controls. Thus, within the limitations of this study, it can be considered a biocompatible sealer with acceptable tissue tolerance

Improve Of Health Care Systems in Subareas of Saudi Arabia by GIS

This paper shows how Geographical Information Systems (GIS) can be used to support health planners and demands on a micro-scale and explores the possibilities of using GIS for health care services in hospitals at Saudi Arabia subareas. GIS has several useful functions and tools that can be used in health planning field. The first part of this paper explains the issues that affect a local health care planning and monitoring of catchment area and facilities management. Each one of these issues is covered using several GIS functions including network analysis and spatial data analysis. The second part defines GIS and its possible application in the health care field. In this section, the relevant GIS functions have also been explained. The third part of this paper discusses the created and implemented a GIS application models, which is made for a local health care centre in Makkahh region and Taif city in Saudi Arabia. All the produced models can be applied on any private or public hospital in Makkahh region  and Taif city. They can be used to build a spatial decision making support system for hospitals in Taif region and serves five local health services neighborhoods named as Turabah, Al-Khurma, Rania, Zulam and Al-Moya. In this paper; the former is used to produce drive-time hospital service area and the route is applied at the selected hospital to calculate the size of its served demand. Finally; in this work, three sets of GIS models have been produced. These are catchment area; patient profile and patient distribution; and patient flows models. So, the output of creating and implementing a GIS models are produced to help a local health planners in their health care decision making output.

Molecular Identification of Ladybird Beetles (Coccinella: Coccinellidae) Using DNA Barcodes

DNA barcoding is a molecular genetics technique commonly applied for species identification based on the cytochrome c oxidase subunit I (COI) gene located on the mitochondrial DNA genome. Based on our analysis, the DNA barcodes were generated from 16 specimen of Coccinella (family Coccinellidae). All the samples were collected from diverse sites in Egypt and Libya. Morphological traits based on the number of dorsal spots, DNA extraction, PCR amplification of COI, sequencing, nucleotide BLAST, and phylogenetics analyses were used to classify the specimens. A phylogenetic tree was constructed using the maximum likelihood method, including 46 COI sequences (the study and NCBI sequences). Three Coccinella clusters were defined and classified as Coccinella septempunctata, Coccinella novemnotata, and Coccinella undecimpunctata each species clustered into a unique branch. DNA barcodes discriminated clearly against the analyzed species. This study validated the COI efficiency as a marker for DNA barcoding of insects (Coccinella, family Coccinellidae)