Linearized modified gravity theories with a cosmological term: advance of perihelion and deflection of light

Two different ways of generalizing Einstein's general theory of relativity with a cosmological constant to Brans-Dicke type scalar-tensor theories are investigated in the linearized field approximation. In the first case a cosmological constant term is coupled to a scalar field linearly whereas in the second case an arbitrary potential plays the role of a variable cosmological term. We see that the former configuration leads to a massless scalar field whereas the latter leads to a massive scalar field. General solutions of these linearized field equations for both cases are obtained corresponding to a static point mass. Geodesics of these solutions are also presented and solar system effects such as the advance of the perihelion, deflection of light rays and gravitational redshift were discussed. In general relativity cosmological constant has no role on these phenomena. We see that for the Brans-Dicke theory the cosmological constant has also no effect on these phenomena. This is because solar system observations require very large values of the Brans-Dicke parameter and the correction terms to these phenomena becomes identical to GR for these large values of this parameter. This result is also observed for the theory with arbitrary potential if the mass of the scalar field is very light. For a very heavy scalar field, however, there is no such limit on the value of this parameter and there are ranges of this parameter where these contributions may become relevant in these scales. Galactic and intergalactic dynamics is also discussed for these theories at the latter part of the paper with similar conclusions.Comment: 25 pages, Revtex. V2: two new sections discussing galactic and intergalactic phenomena are added, discussion is extended, references added, Published version

Gravitational waves in Brans-Dicke Theory with a cosmological constant

Weak field gravitational wave solutions are investigated in Brans-Dicke (BD) theory in the presence of a cosmological constant. In this setting the background geometry is not flat but asymptotically de-Sitter. We investigate the linearised field equations, and their gravitational wave solutions in a certain gauge choice. We will show that this theory leads to massless scalar waves as in original BD theory and in contrast to massive BD theory. The effects of these waves on free particles and their polarization properties are studied extensively and effects of the cosmological constant is analyzed in these phenomena in detail. The energy flux of these waves are also discussed in this background. By analyzing this flux, we obtain a critical distance where the waves cannot propagate further, which extends Cosmic no Hair Conjecture (CNC) to BD theory with a cosmological constant.Comment: 27 pages, Revtex 4-

What are the relationship between problematic Internet use and subjective well-being and self-esteem? Investigation of an adolescent sample

The aim of this research is to determine whether subjective well-being and self-esteem predict problematic internet use or not. Within the scope of the study, the differentiation of problematic internet use according to some demographic variables was assessed. The study group for the research comprised 385 high school students (203 females, 182 males) attending 6 high schools in Trabzon province. Data were collected using the Problematic Internet Use Scale-E, Subjective Well-Being Scale, Coopersmith Self-Esteem Inventory and a Demographic Information Form. The results showed there was a negative significant correlation between problematic internet use with subjective well-being and self-esteem. Additionally, it was concluded that subjective well-being and self-esteem significantly predicted problematic internet use. Problematic internet use differed according to gender, family income level, duration spent on the internet, purpose of internet use and maternal education level, while it did not differ according to class level or paternal education level

A Research on the determination of students' general ınternship problems for associate degree program in tourism and hotel management

Turizm ve otel işletmeciliğinde okuyan öğrencilerin turizm sektörüne yönelik görüşleri daha çok staj dönemlerinde şekillenmeye başlamaktadır. Ancak staj sürecinde zaman zaman gerek eğitim kurumu, gerek işletme ve gerekse öğrenci kaynaklı birtakım problemler yaşanmaktadır. Yaşanan problemler ya stajın verimsizliğine ya da kalifiye personelin turizm sektöründen uzaklaşarak farklı alanlarda kariyer yapma isteğine yol açmaktadır. Bundan yola çıkarak, bu çalışmanın amacı ön lisans düzeyinde turizm eğitimi alan, staj deneyimine sahip öğrencilerin, staj sürecinde staj yaptıkları işletmelerden ve öğrenim gördükleri kurumlardan kaynaklanan sorunlar hakkında öğrencilerin kişisel düşünce ve deneyimlerinin alınarak, yaşanan sorunların çözümüne yönelik görüşler sunmak ve turizm eğitiminin daha verimli hale getirilmesidir. Araştırmanın kapsamını Afyon Kocatepe Üniversitesi Turizm ve Otel İşletmeciliği Programı önlisans öğrencileri içerisinde stajını tamamlayan öğrenciler oluşturmaktadır. Çalışmada konu hakkında değerlendirmeler yapabilmek için nitel araştırma yöntemlerinden odak grup görüşme tekniğiyle veriler toplanıp yorumlanmaya çalışılmıştır. Görüşmenin ilk aşamasında öncelikle bir açıklama konuşması yapılarak görüşmecilerin birbirleriyle tanıştırılması sağlanmıştır. İkinci aşamasında görüşme başlıkları görüşmecilere bildirilerek konu hakkında her birinin kısa görüşleri alınarak, öncelikle yarı yapılandırılmış sorular daha sonra görüşme sürecinde ortaya çıkan yapılandırılmamış sorular sorularak grubun sorular karşısında kendi aralarında tartışmaları sağlanmıştır. Böylece konu hakkında benzer ve farklı görüşler tespit edilmeye çalışılmıştır. Çalışmanın son bölümünde ise yapılan odak grup görüşmesi çalışmasından elde edilen birincil veriler değerlendirilerek öğrencilerin staj uygulamalarında karşılaştıkları çeşitli sorunlar hakkında sonuçlar elde edilmiştir. Elde edilen bulgular değerlendiğinde turizm öğrencilerinin staj dönemlerinde pek çok olumsuzluklarla karşılaşmalarına rağmen mesleki eğitim içerisinde stajın önemli ve mutlaka uygulanması gereken bir eğitim olması noktasında birleştiklerini görülmüştür. Öğrencilerin staj sorunları hakkında en mağdur oldukları ortak konu başlıkları ise; sektörde eğitimli insan sayısının azlığı ve bu durumun staj çalışmalarını olumsuz etkilemesi, ucuz işgücü olarak görülmeleri, fazla iş yükü ve kadrolu çalışan muamelesi ile çalışma saatleri ve ücret olarak tespit edilmiştir. Çalışmanın son bölümünde, ortaya çıkan sonuçlar çerçevesinde staj uygulamalarının daha sorunsuz uygulanabilir hale getirilebilmesi için çözüm önerileri sunulmuştur.The opinions of the students studying in tourism and hotel management are starting to be shaped mostly during the internship period. However, there are some problems in the internship process time to time caused by the educational institution, business and students. These problems lead to internship inefficiency or desire of qualified personnel to move away from the tourism sector and have a career in different fields. From this point of view, the aim of this study is to make the tourism education more productive by taking consideration of the personal thoughts and experiences of the students about the problems arising from students, who have experience of internship in the pre-license level of this study, arising from the enterprises they have trained in internship and institutions they have studied. The scope of this research is Afyon Kocatepe University Tourism and Hotel Management Program students that complete their internship in 2014-2015 academic years. In this study, the focus group interview technique was used to collect and interpret qualitative research methods in order to evaluate the data. In the first phase of the interview, an explanatory talk was done and the interviewers were introduced to each other. In the second phase, interview topics were reported to the interviewees by taking brief opinions of each of them on the issues, and semi-structured questions were asked at first. Later on unstructured questions arise out of the interview process were asked to interviewers to enable discussions among them. Thus, attempts have been made to identify similar and different views on the subject. In the last part of the study, the primary data obtained from the focus group interview study were evaluated and various problems that students encountered in internship practices were come out as a result. After evaluation, it is seen that tourism students have a lot of problems during the internship periods but they are all agreed at the point of being vocational education training must be practiced. The most common topics that students are aggrieved about internship problems are; low number of educated people in the sector and the negative effects of this situation on their internship works, being seen as cheap labor force, overworked and permanent employee treatment, working hours and wages. In the last part of the study, a solution proposal will be presented in order to make internship applications more smoothly applicable within the framework of the results

OZONE IMPROVES AUTOGENOUS GRAFT HEALING IN EXPERIMENTAL DIABETES MELLITUS: A MORPHOMETRIC AND IMMUNOHISTOCHEMICAL STUDY

Backround: Diabetes mellitus (DM) is a metabolic disorder which plays crucial role in the pathogenesis of periodontitis. Ozone have several actions such as antimicrobial ,immunostimulating, antihypoxic effects, and activates antioxidant enzymes and angiogenesisAim: The aim of this study is to investigate the effect of gaseous ozone on bone healing in diabetic rat calvarial defects treated with autogenous bone graft, morphometrically and immunohistochemically.Material and Methods: Diabetes was induced and critical size defects were created on rats. Study groups: 1-Empty defect (Control, n=14) group, 2-Autograft (AG, n=14) group, 3-Empty defect+ozone therapy (Control+Ozone, n=14) group, 4-Autograft+ozone application (AG+Ozone, n=14) group. Gaseous ozone was applied on the operation day and the following 2 weeks daily (140ppm @ 2L/d, 2.24 mg). Total bone area was measured. Osteocalcin and Bone morphogenic protein-2  protein expressions were evaluated.Results: Control and Control+Ozone groups had no osteoclast and residuel lacunae during the study . Osteoblasts in AG+Ozone group were higher than AG group at 4th week (p>0.05). AG+Ozone group had more total bone area than AG group at 4th week. AG+Ozone group revealed more BMP-2 immune positivity compared to the other groups. Osteocalcin immune positivity in AG groups was higher than those of the Control groups.Conclusion: Within the limitations of this study, gaseous ozone application decreased osteoclast number and increased osteoblast number and bone regeneration, especially, in early stages of bone regeneration in diabetic rats. KEYWORDS: autograft, bone regeneration, calvarial defect, experimental diabetes mellitus, ozon

Eating disorders, primary care, and stigma: an analysis of research trends and patterns

Eating disorders (EDs) are a growing concern affecting millions worldwide. Early detection and treatment are crucial, but stigma can prevent people from seeking help. Primary care providers can play a critical role in early detection by coordinating care with other professionals. Understanding the research landscape on EDs, primary care, and stigma is essential for identifying knowledge gaps to direct future research and improve management. In this study, we aimed to analyze the scientific trends and patterns in research about EDs, primary care, and stigma. A bibliometric analysis was conducted using the Web of Science database to collect articles published between May 1986 and May 2023. Bibliometric indicators were utilized to examine authorship, collaboration patterns, and influential papers. Topic analysis was performed to identify stigma-related terms within the dataset. A total of 541 research articles were analyzed, and it was found that the average number of publications per year has increased linearly from nearly zero in 1986 to 41 in 2022. One of the study’s main findings is that despite this linear increase over the years, the subject of stigma did not take a prominent place in the literature. Only a few stigma concepts could be identified with the topic analysis. The authors in the field are also interested in; screening, neurotic symptoms, training, adolescent, obesity-related conditions, and family. One-third of all publications were from 15 journals. However, only two of them were primary healthcare journals. Leading authors’ collaborations were another critical finding from the network analysis. This may help to expand primary care related EDs research to end the mental health stigma. This study provides insights into the research trends and patterns regarding eating disorders, primary care, and stigma. Our findings highlight the need to address primary care’s impact and stigma on EDs. The identified research gaps can guide future studies to improve the prevention, diagnosis, and treatment of eating disorders in primary care settings

Immobilization of a Bifidobacterial Endo-\u3ci\u3eß-N\u3c/i\u3e-Acetylglucosaminidase to Generate Bioactive Compounds for Food Industry

Conjugated N-glycans are considered next-generation bioactive prebiotic compounds due to their selective stimulation of beneficial microbes. These compounds are glycosidically attached to proteins through N-acetylglucosamines via specific asparagine residue (AsN-X-Ser/Thr). Certain bacteria such as Bifidobacterium longum subspecies infantis (B. infantis) have been shown to be capable of utilizing conjugated N-glycans, owing to their specialized genomic abilities. B. infantis possess a unique enzyme, Endo-ß-N-acetylglucosaminidase (EndoBI-1), which cleaves all types of conjugated N-glycans from glycoproteins. In this study, recombinantly cloned EndoBI- 1 enzyme activity was investigated using various immobilization methods: 1) adsorption, 2) entrapment-based alginate immobilization, 3) SulfoLink-, and 4) AminoLink-based covalent bonding immobilization techniques were compared to develop the optimum application of EndoBI-1 to food processes. The yield of enzyme immobilization and the activity of each immobilized enzyme by different approaches were investigated. The N-glycans released from lactoperoxidase (LPO) using different immobilized enzyme forms were characterized using MALDI-TOF mass spectrometry (MS). As expected, regardless of the techniques, the enzyme activity decreased after the immobilization methods. The enzyme activity of adsorption and entrapment-based alginate immobilization was found to be 71.55% ± 0.6 and 20.32% ± 3.18, respectively, whereas the activity of AminoLink- and SulfoLink-based covalent bonding immobilization was found to be 58.05 ± 1.98 and 47.49% ± 0.30 compared to the free form of the enzyme, respectively. However, extended incubation time recovery achieved activity similar to that of the free form. More importantly, each immobilization method resulted in the same glycan profile containing 11 different N-glycan structures from a model glycoprotein LPO based on MALDI-TOF MS analysis. The glycan data analysis suggests that immobilization of EndoBI-1 is not affecting the enzyme specificity, which enables full glycan release without a limitation. Hence, different immobilization methods investigated in this study can be chosen for effective enzyme immobilization to obtain bioactive glycans. These findings highlight that further optimization of these methods can be a promising approach for future processing scale-up and commercialization of EndoBI- 1 and similar enzymes

Recent Advances in Health Biotechnology During Pandemic

The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which emerged in 2019, cut the epoch that will make profound fluctuates in the history of the world in social, economic, and scientific fields. Urgent needs in public health have brought with them innovative approaches, including diagnosis, prevention, and treatment. To exceed the coronavirus disease 2019 (COVID-19) pandemic, various scientific authorities in the world have procreated advances in real time polymerase chain reaction (RT-PCR) based diagnostic tests, rapid diagnostic kits, the development of vaccines for immunization, and the purposing pharmaceuticals for treatment. Diagnosis, treatment, and immunization approaches put for- ward by scientific communities are cross-fed from the accrued knowledge of multidisciplinary sciences in health biotechnology. So much so that the pandemic, urgently prioritized in the world, is not only viral infections but also has been the pulsion in the development of novel approaches in many fields such as diagnosis, treatment, translational medicine, virology, mi- crobiology, immunology, functional nano- and bio-materials, bioinformatics, molecular biol- ogy, genetics, tissue engineering, biomedical devices, and artificial intelligence technologies. In this review, the effects of the COVID-19 pandemic on the development of various scientific areas of health biotechnology are discussed