Dymnikova-Schwinger traversable wormholes

In this paper, we obtain new $d$-dimensional and asymptotically flat wormhole solutions by assuming a specific form of the energy density distribution. This is addressed by considering the generalization of the so-called Dymnikova model, originally studied in the context of regular black holes. In this way, we find constraints for the involved parameters, namely, the throat radius, the scale associated to the matter distribution, and the spacetime dimension, to build those wormholes. Following, we study the properties of the obtained solutions, namely, embedding diagrams as well as Weak and Null Energy Conditions (WEC and NEC). We show that the larger the dimension, the larger the flatness of the wormhole and the more pronounced the violation of these energy conditions. We also show that the corresponding fluid behaves as phantom-like for $d \geq 4$ in the neighborhood of the wormhole throat. In addition, we specialize the employed model for $d=4$ spacetime, associating it with the gravitational analog of the Schwinger effect in a vacuum and correcting the model by introducing a minimal length via Generalized Uncertainty Principle (GUP). Thus, we obtain a novel traversable and asymptotically flat wormhole solution by considering that the minimal length is very tiny. The associated embedding diagram shows us that the presence of this fundamental quantity increases the slope of the wormhole towards its throat compared with the case without it. That correction also attenuates the WEC (and NEC) violations nearby the throat, with the fluid ceasing to be a phantom-type at the Planck scale, unlike the case without the minimal length.Comment: 18 page

Improvement of special events organization through application of group decision making system

Rezime: Cilj ove doktorske diseratcije jeste da objasni ulogu specijalnog dogadaja kako kod nas, tako i u medunarodnim okvirima. Od davnih vremena ljudi se okupljaju raznim povodima. Dogadaji te vrste predstavljali su posebni i nesvakidašnji doživljaj. Takvi dogadaji nisu bili cesti, vec su bili specijalni i odigravali se kao posledica odredenih okolnosti ili na zahtev pojedinca, odredenih grupa i vladajuceg sistema. Upravo zbog toga su sa sobom nosili efekat ushicenja i neponovljivog. Industrija slobodnog vremena i zabave danas, predstavlja oblast koja je u žiži interesovanja. U prethodnih nekoliko godina se izuzetno razvila i zauzima posebno mesto na tržištu usluga i daje pregršt novih ideja i nacina da se one ostvare. Profesionalne agencije koje se bave ovim vidovima organizovanja su izuzetno popularne u svetu i zauzimaju znacajno mesto na pijadestalu uspeha, profita i povratnih informacija koje se dobijaju od zadovoljnih klijenata. Sa druge strane odlucivanje je deo poslova koje svaki menadžer treba da obavlja u toku svog rada. Te odluke se donose stalno, tj. u toku obavljanja, odnosno izvršavanja poslova vezanih za klasicne upravljacke funkcije kao i prilikom organizacije specijalnog dogadaja. Odlucivanje nije posebna, izolovana funkcija upravljanja, vec je zajednicki imenilac svim ostalim funkcijama. Menadžeri na svim nivoima organizacije su angažovani na donošenju razlicitih odluka od operativnih, taktickih do strateških. U okviru ove disertacije, posmatra se kako je moguce unaprediti organizaciju specijalnog dogadaja, primenom sistema grupnog odlucivanja.Summary: The aim of this doctoral dissertation is to explain the role of special events in our country and in the international context. Since ancient times, people have been gathering on various occasions. Events of this kind considered a special and unusual experience. Such events were held rarely. They were special, and took place as a result of certain circumstances, or at the request of an individual, or certain groups of government system. For this reason, they were bringing the excitement and unique effect. Leisure and entertainment industry is in major focus today. In the past several years, it has rapidly developed, and now it has a special place on the service market, generating plenty of new ideas how to perform services of this kind. Professional agencies that deal with event organization are very popular worldwide, and they occupy significant share in business success, profit and feedback obtained from satisfied customers in service industry, on global level. On the other hand, decision making is the activity that every manager needs to perform during work time. The decisions are made all the time, during the execution of duties related to the classical management functions, but also when organizing the special event. Decision making is not a separate, isolated management function, but the common denominator of all other functions. Managers at all levels of the organizational hierarchy are involved in various decisions, from operational, tactical, to strategic ones. This dissertation will present how the usage group decision making system can improve the organization of special events

Dymnikova GUP-corrected black holes

We consider the impact of Generalized Uncertainty Principle (GUP) effects on the Dymnikova regular black hole. The minimum length scale introduced by the GUP modifies the energy density associated with the gravitational source, referred to as the Dymnikova vacuum, based on its analogy with the gravitational counterpart of the Schwinger effect. We present an approximated analytical solution (together with exact numerical results for comparison) that encompasses a wide range of black hole sizes, spanning from microscopic (Planckian and sub-Planckian) to macroscopic scales, whose properties crucially depend on the ratio between the de Sitter core radius and the GUP scale. The emergence of a wormhole inside de Sitter core in the innermost region of the object is one of the most relevant features of this family of solutions. Our findings demonstrate that these solutions remain singularity free, confirming the robustness of the Dymnikova regular black hole under GUP corrections. Regarding energy conditions, we find that the violation of the strong, weak, and null energy conditions which is characteristic of the pure Dymnikova case does not occur at Planckian scales in the GUP corrected solution. This contrast suggests a departure from conventional expectations and highlights the influence of quantum corrections and the GUP in modifying the energy conditions near the Planck scale

Ion microprobe study of the polarization quenching techniques in single crystal diamond radiation detectors

Synthetic single crystal diamond grown using the chemical vapor deposition technique constitutes an extraordinary candidate material for monitoring radiation in extreme environments. However, under certain conditions, a progressive creation of space charge regions within the crystal can lead to the deterioration of charge collection efficiency. This phenomenon is called polarization and represents one of the major drawbacks associated with using this type of device. In this study, we explore different techniques to mitigate the degradation of signal due to polarization. For this purpose, two different diamond detectors are characterized by the ion beam-induced charge technique using a nuclear microprobe, which utilizes MeV energy ions of different penetration depths to probe charge transport in the detectors. The effect of polarization is analyzed by turning off the bias applied to the detector during continuous or discontinuous irradiation, and also by alternating bias polarity. In addition, the beneficial influence of temperature for reducing the effect of polarization is also observed. Finally, the effect of illuminating the detector with light is also measured. Our experimental results indicate that heating a detector or turning off the bias, and then applying it during continuous irradiation can be used as satisfactory methods for recovering the CCE value close to that of a prepolarized state. In damaged regions, illumination with white light can be used as a standard method to suppress the strength of polarization induced by hole

Origin of the Superconductivity in the Y-Sr-Ru-O and Y-Sr-Cu-O Systems

We report on the structural, magnetic, and Raman-scattering studies of double perovskite structure Sr2Y(Ru1-xCux)O6-d systems made by systematic synthesis processes with various numbers of doping concentrations and sintering temperatures. We observed different behaviors resulting from the different thermal treatments. In particular, superconductivity in Cu-doped Sr2YRuO6 has been observed only for partially melted ceramic materials. We show that superconductivity is associated with the 1:2:3 phase (YSr2Cu3Ot), similar to that of Y-Sr-Cu-O samples sintered at high temperature

Systematic assessment of the growth plates of the wrist in young gymnasts: Development and validation of the Amsterdam MRI assessment of the Physis (AMPHYS) protocol

Objectives To develop and validate a protocol for MRI assessment of the distal radial and ulnar periphyseal area in gymnasts and non-gymnasts. Methods Twenty-four gymnasts with wrist pain, 18 asymptomatic gymnasts and 24 non-gymnastic controls (33 girls) underwent MRI of the wrist on a 3T scanner. Sequences included coronal proton density-weighted images with and without fat saturation, and three-dimensional water-selective cartilage scan and T2 Dixon series. Skeletal age was determined using hand radiographs. Three experienced musculoskeletal radiologists established a checklist of possible (peri)physeal abnormalities based on literature an

Response of GaN to energetic ion irradiation: conditions for ion track formation

We investigated the response of wurzite GaN thin films to energetic ion irradiation. Both swift heavy ions (92 MeV Xe23+, 23 MeV I6+) and highly charged ions (100 keV Xe40+) were used. After irradiation, the samples were investigated using atomic force microscopy, grazing incidence small angle X-ray scattering, Rutherford backscattering spectroscopy in channelling orientation and time of flight elastic recoil detection analysis. Only grazing incidence swift heavy ion irradiation induced changes on the surface of the GaN, when the appearance of nanoholes is accompanied by a notable loss of nitrogen. The results are discussed in the framework of the thermal spike model

A systematic framework for selecting gene-condition pairs for inclusion in newborn sequencing panels: Early Check implementation

Purpose Research is underway worldwide to investigate the feasibility, acceptability, and utility of sequencing-based newborn screening. Different methods have been used to select gene-condition pairs for screening, leading to highly inconsistent gene lists across studies. Methods Early Check developed and utilized actionability-based frameworks for evaluating gene-condition pairs for inclusion in newborn panels (Panel 1 - high actionability, Panel 2 - possible actionability). A previously developed framework, the Age-based Semi Quantitative Metric (ASQM), was adapted. Increasing ASQM scores, with a maximum of 15, suggest greater actionability. Wilcoxon tests were performed to compare Panel 1 gene-condition pairs on the Recommended Uniform Screening Panel (RUSP) to non-RUSP pairs. Results In our first round of assessment, Early Check identified 178 gene-condition pairs for inclusion in Panel 1 and 29 for Panel 2. Median ASQM scores of RUSP conditions on Panel 1 was 12 (range 4 to 15) and non-RUSP was 13 (range 9 to 15). Median scores for Panel 2 was 10 (range 6 to 14). Conclusion The Early Check frameworks provide a transparent, semiquantitative, and reproducible methodology for selecting gene-condition pairs for NBS sequencing pilot studies that may inform future integration of genomic sequencing into population-level NBS. Collaborative efforts among newborn sequencing studies to establish shared criteria is needed to enhance cross-study comparisons

Parental Guidance Suggested: Engaging Parents as Partners in Research Studies of Genomic Screening for a Pediatric Population

Recent advances in genomic sequencing and genomic medicine are reshaping the landscape of clinical care. As a screening modality, genetic sequencing has the potential to dramatically expand the clinical utility of newborn screening (NBS), though significant barriers remain regarding ethical, legal, and social implications (ELSI) and technical and evidentiary challenges. Stakeholder-informed implementation research is poised to grapple with many of these barriers, and parents are crucial stakeholders in this process. We describe the formation and activities of a Community Research Board (CRB) composed of parents with diverse backgrounds assembled to participate in an ongoing research partnership with genomic and public health researchers at the University of North Carolina. The mission of the CRB is to provide insight into parental perspectives regarding the prospect of adding genomic sequencing to NBS and collaboratively develop strategies to ensure its equitable uptake. We describe how these contributions can improve the accessibility of research and recruitment methods and promote trust and inclusivity within diverse communities to maximize the societal benefit of population genomic screening in healthy children

Reactivity of Metal-Free and Metal-Associated Amyloid-?? with Glycosylated Polyphenols and Their Esterified Derivatives

Both amyloid-?? (A??) and transition metal ions are shown to be involved in the pathogenesis of Alzheimer???s disease (AD), though the importance of their interactions remains unclear. Multifunctional molecules, which can target metal-free and metal-bound A?? and modulate their reactivity (e.g., A?? aggregation), have been developed as chemical tools to investigate their function in AD pathology; however, these compounds generally lack specificity or have undesirable chemical and biological properties, reducing their functionality. We have evaluated whether multiple polyphenolic glycosides and their esterified derivatives can serve as specific, multifunctional probes to better understand AD. The ability of these compounds to interact with metal ions and metal-free/-associated A??, and further control both metal-free and metal-induced A?? aggregation was investigated through gel electrophoresis with Western blotting, transmission electron microscopy, UV-Vis spectroscopy, fluorescence spectroscopy, and NMR spectroscopy. We also examined the cytotoxicity of the compounds and their ability to mitigate the toxicity induced by both metal-free and metal-bound A??. Of the polyphenols investigated, the natural product (Verbascoside) and its esterified derivative (VPP) regulate the aggregation and cytotoxicity of metal-free and/or metal-associated A?? to different extents. Our studies indicate Verbascoside represents a promising structure for further multifunctional tool development against both metal-free A?? and metal-A??.open0