bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of 3.5 million SARS-CoV-2 sequences reveals unique mutational trends with consistent nucleotide and codon frequencies
Authors: Fumagalli Sarah E. , Padhiar Nigam H. , Meyer Douglas , Katneni Upendra , Bar Haim , DiCuccio Michael , Komar Anton A. , Kimchi-Sarfaty Chava
Published: February 2023

Background

Since the onset of the SARS-CoV-2 pandemic, bioinformatic analyses have been performed to understand the nucleotide and synonymous codon usage features and mutational patterns of the virus. However, comparatively few have attempted to perform such analyses on a considerably large cohort of viral genomes while organizing the plethora of available sequence data for a month-by-month analysis to observe changes over time. Here, we aimed to perform sequence composition and mutation analysis of SARS-CoV-2, separating sequences by gene, clade, and timepoints, and contrast the mutational profile of SARS-CoV-2 to other comparable RNA viruses.

Methods

Using a cleaned, filtered, and pre-aligned dataset of over 3.5 million sequences downloaded from the GISAID database, we computed nucleotide and codon usage statistics, including calculation of relative synonymous codon usage values. We then calculated codon adaptation index (CAI) changes and a nonsynonymous/synonymous mutation ratio (dN/dS) over time for our dataset. Finally, we compiled information on the types of mutations occurring for SARS-CoV-2 and other comparable RNA viruses, and generated heatmaps showing codon and nucleotide composition at high entropy positions along the Spike sequence.

Results

We show that nucleotide and codon usage metrics remain relatively consistent over the 32-month span, though there are significant differences between clades within each gene at various timepoints. CAI and dN/dS values vary substantially between different timepoints and different genes, with Spike gene on average showing both the highest CAI and dN/dS values. Mutational analysis showed that SARS-CoV-2 Spike has a higher proportion of nonsynonymous mutations than analogous genes in other RNA viruses, with nonsynonymous mutations outnumbering synonymous ones by up to 20:1. However, at several specific positions, synonymous mutations were overwhelmingly predominant.

Conclusions

Our multifaceted analysis covering both the composition and mutation signature of SARS-CoV-2 gives valuable insight into the nucleotide frequency and codon usage heterogeneity of SARS-CoV-2 over time, and its unique mutational profile compared to other RNA viruses.
Is abaloparatide more efficacious on increasing bone mineral density than teriparatide for women with postmenopausal osteoporosis? An updated meta-analysis
Authors: Hong Pan , Liu Ruikang , Rai Saroj , Liu JiaJia , Zhou YeMing , Zheng Yu , Li Jin
Published: February 2023

Purpose

Osteoporosis poses a challenge to public health, causing fragility fractures, especially in postmenopausal women. Abaloparatide (ABL) is an effective anabolic agent to improve bone formation and resorption among postmenopausal women with osteoporosis. Our meta-analysis aims to assess the effectiveness and safety of ABL versus teriparatide (TPTD) in improving bone mineral density (BMD).

Methods

We searched Medline, Embase, Web of Science, Cochrane databases and Clinicaltrial.gov until September 2, 2022. We included data from randomized controlled trials (RCTs) and post hoc analyses of RCTs. Outcomes included BMD change from baseline and risks of adverse events. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) tool was used to evaluate the quality of outcomes.

Results

Four studies including 16 subgroups were included in this study. In particular, RCTs with head-to-head comparisons of ABL and TPTD were used in the meta-analysis, and all were from manufacturer-sponsored trials. All parameters in 24 weeks except lumbar spine (versus TPTD) showed significant advantages in the ABL group. Only the results of two subgroups in ABL versus TPTD demonstrated High GRADE quality (femoral neck: weighted mean difference (WMD) = 1.58 [0.52, 2.63]; Total hip: WMD = 1.46 [0.59, 2.32]). However, our fracture data were insufficient. Besides, we found no evident difference in serious adverse events or deaths in either group and the incidence of hypercalcemia in the ABL group lessened by 51% compared with the TPTD group. Nevertheless, compared with placebo, ABL demonstrated higher risks of nausea and palpitations.

Conclusion

ABL demonstrated a beneficial effect on BMD compared to both placebo and TPTD for postmenopausal women with osteoporosis. ABL also had insignificantly lowered adverse event risk than TPTD. ABL is an alternative for patients with postmenopausal osteoporosis.
Comparative effectiveness of a mindfulness-based intervention (M-Body) on depressive symptoms: study protocol of a randomized controlled trial in a Federally Qualified Health Center (FQHC)
Authors: Burnett-Zeigler Inger , Zhou Elayne , Martinez Jennifer H. , Zumpf Katelyn , Lartey Lynette , Moskowitz Judith T. , Wisner Katherine L. , McDade Thomas , Brown C. Hendricks , Gollan Jacqueline , Ciolino Jody D. , Schauer Jacob M. , Petito Lucia C.
Published: February 2023

Background

Mindfulness-based interventions have been shown to improve psychological outcomes including stress, anxiety, and depression in general population studies. However, effectiveness has not been sufficiently examined in racially and ethnically diverse community-based settings. We will evaluate the effectiveness and implementation of a mindfulness-based intervention on depressive symptoms among predominantly Black women at a Federally Qualified Health Center in a metropolitan city.

Methods

In this 2-armed, stratified, individually randomized group-treated controlled trial, 274 English-speaking participants with depressive symptoms ages 18–65 years old will be randomly assigned to (1) eight weekly, 90-min group sessions of a mindfulness-based intervention (M-Body), or (2) enhanced usual care. Exclusion criteria include suicidal ideation in 30 days prior to enrollment and regular (>4x/week) meditation practice. Study metrics will be assessed at baseline and 2, 4, and 6 months after baseline, through clinical interviews, self-report surveys, and stress biomarker data including blood pressure, heart rate, and stress related biomarkers. The primary study outcome is depressive symptom score after 6 months.

Discussion

If M-Body is found to be an effective intervention for adults with depressive symptoms, this accessible, scalable treatment will widely increase access to mental health treatment in underserved, racial/ethnic minority communities.

Trial registration

ClinicalTrials.gov NCT03620721. Registered on 8 August 2018.
Distance-based delivery of exercise for people treated for breast, prostate or colorectal cancer: a study protocol for a randomised controlled trial of EX-MED Cancer Sweden
Authors: Kotte Melissa , Bolam Kate A. , Mijwel Sara , Altena Renske , Cormie Prue , Wengström Yvonne
Published: February 2023

Background

Regular exercise has been shown to have beneficial health effects in cancer survivors, including improving quality of life and other important health outcomes. However, providing people with cancer with easily accessible, high-quality exercise support and programs is a challenge. Therefore, there is a need to develop easily accessible exercise programs that draw upon the current evidence. Supervised, distance-based exercise programs have the benefit of reaching out to many people whilst providing the support of an exercise professional. The aim of the EX-MED Cancer Sweden trial is to examine the effectiveness of a supervised, distance-based exercise program, in people previously treated for breast, prostate, or colorectal cancer, on health-related quality of life (HRQoL), as well as other physiological and patient-reported health outcomes.

Methods

The EX-MED Cancer Sweden trial is a prospective randomised controlled trial including 200 people that have completed curative treatment for breast, prostate, or colorectal cancer. Participants are randomly allocated to an exercise group or a routine care control group. The exercise group will participate in a supervised, distanced-based exercise program delivered by a personal trainer who has undertaken specialised exercise oncology education modules. The intervention consists of a combination of resistance and aerobic exercises with participants completing two 60-min sessions per week for 12 weeks. The primary outcome is HRQoL (EORTC QLQ-C30) assessed at baseline, 3- (end of intervention and primary endpoint) and 6-months post-baseline. Secondary outcomes are physiological (cardiorespiratory fitness, muscle strength, physical function, body composition) and patient-reported outcomes (cancer-related symptoms, fatigue, self-reported physical activity), and self-efficacy of exercise. Furthermore, the trial will explore and describe the experiences of participation in the exercise intervention.

Discussion

The EX-MED Cancer Sweden trial will provide evidence regarding the effectiveness of a supervised, distance-based exercise program for survivors of breast, prostate, and colorectal cancer. If successful, it will contribute to the implementation of flexible and effective exercise programs as part of the standard of care for people following cancer treatment, which is likely to contribute to a reduction in the burden of cancer on the individual, health care system and society.

Trial registration

www.ClinicalTrials.gov NCT05064670. Registered on October 1, 2021.
Perspectives on reasons for suicidal behaviour and recommendations for suicide prevention in Kenya: qualitative study
Authors: Ongeri Linnet , Nyawira Miriam , Kariuki Symon M. , Bitta Mary , Schubart Chris , Penninx Brenda W. J. H. , Newton Charles R. J. C. , Tijdink Joeri K.
Published: February 2023

Background

Little is known about the reasons for suicidal behaviour in Africa, and communities’ perception of suicide prevention. A contextualised understanding of these reasons is important in guiding the implementation of potential suicide prevention interventions in specific settings.

Aims

To understand ideas, experiences and opinions on reasons contributing to suicidal behaviour in the Coast region of Kenya, and provide recommendations for suicide prevention.

Method

We conducted a qualitative study with various groups of key informants residing in the Coast region of Kenya, using in-depth interviews. Audio-recorded interviews were transcribed and translated from the local language before thematic inductive content analysis.

Results

From the 25 in-depth interviews, we identified four key themes as reasons given for suicidal behaviour: interpersonal and relationship problems, financial and economic difficulties, mental health conditions and religious and cultural influences. These reasons were observed to be interrelated with each other and well-aligned to the suggested recommendations for suicide prevention. We found six key recommendations from our thematic content analysis: (a) increasing access to counselling and social support, (b) improving mental health awareness and skills training, (c) restriction of suicide means, (d) decriminalisation of suicide, (e) economic and education empowerment and (f) encouraging religion and spirituality.

Conclusions

The reasons for suicidal behaviour are comparable with high-income countries, but suggested prevention strategies are more contextualised to our setting. A multifaceted approach in preventing suicide in (coastal) Kenya is warranted based on the varied reasons suggested. Community-based interventions will likely improve and increase access to suicide prevention in this study area.
DNA Methylation Near CPT1A and Changes in Triglyceride-rich Lipoproteins in Response to Weight-loss Diet Interventions
Authors: Li Xiang , Shao Xiaojian , Xue Qiaochu , Kou Minghao , Champagne Catherine M , Koseva Boryana S , Heianza Yoriko , Grundberg Elin , Bazzano Lydia A , Bray George A , Sacks Frank M , Qi Lu
Published: February 2023

Context

Carnitine palmitoyltransferase-1A, encoded by the CPT1A gene, plays a key role in the oxidation of long-chain fatty acids in the mitochondria and may be important in triglyceride metabolism. Previous work has shown that high fat intake was negatively associated with CPT1A methylation and positively associated with CPT1A expression.

Objective

We aim to investigate the association of DNA methylation (DNAm) at the CPT1A gene with reductions in triglycerides and triglyceride-rich lipoproteins (TRLs) in response to weight-loss diet interventions.

Methods

The current study included 538 White participants, who were randomly assigned to 1 of 4 diets varying in macronutrient components. We defined the regional DNAm at CPT1A as the average methylation level over CpGs within 500 bp of the 3 triglyceride-related DNAm sites.

Results

Dietary fat intake significantly modified the association between baseline DNAm at CPT1A and 2-year changes in total plasma triglycerides, independent of concurrent weight loss. Among participants assigned to a low-fat diet, a higher regional DNAm level at CPT1A was associated with a greater reduction in total plasma triglycerides at 2 years (P = .01), compared with those assigned to a high-fat diet (P = .64) (P interaction = .018). Further investigation on lipids and apolipoproteins in very low-density lipoprotein (VLDL) revealed similar interaction patterns for 2-year changes in VLDL-triglycerides, VLDL-cholesterol, and VLDL-apolipoprotein B (P interaction = .009, .002, and .016, respectively), but not for VLDL-apoC-III (P interaction = .36).

Conclusion

Participants with a higher regional DNAm level at CPT1A benefit more in long-term improvement in triglycerides, particularly in the TRLs and related apolipoproteins when consuming a low-fat weight-loss diet.
Disease Duration and Chronic Complications Associate With Immune Activation in Individuals With Longstanding Type 1 Diabetes
Authors: Ajie Mandala , van Heck Julia I P , Janssen Anna W M , Meijer Rick I , Tack Cees J , Stienstra Rinke
Published: February 2023

Context

Type 1 diabetes (T1D) is associated with alterations of the immune response which persist even after the autoimmunity aspect is resolved. Clinical factors that cause dysregulation, however, are not fully understood.

Objective

To identify clinical factors that affect immune dysregulation in people with longstanding T1D.

Design

In this cross-sectional study, 243 participants with longstanding T1D were recruited between February 2016 and June 2017 at the Radboudumc, the Netherlands. Blood was drawn to determine immune cell phenotype and functionality, as well as circulating inflammatory proteome. Multivariate linear regression was used to determine the association between glycated hemoglobin (HbA1c) levels, duration of diabetes, insulin need, and diabetes complications with inflammation.

Results

HbA1c level is positively associated with circulating inflammatory markers (P < .05), but not with immune cell number and phenotype. Diabetes duration is associated with increased number of circulating immune cells (P < .05), inflammatory proteome (P < .05), and negatively associated with adaptive immune response against Mycobacterium tuberculosis and Rhizopus oryzae (P < .05). Diabetes nephropathy is associated with increased circulating immune cells (P < .05) and inflammatory markers (P < .05)

Conclusion

Disease duration and chronic complications associate with persistent alterations in the immune response of individuals with long standing T1D.
Insulin-Induced AKR1C3 Induces Fatty Acid Synthase in a Model of Human PCOS Adipocytes
Authors: Paulukinas Ryan D , Penning Trevor M
Published: February 2023

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy in women. In PCOS, insulin resistance and hyperandrogenism could drive the increased risk for cardiometabolic disease. Aldo-keto reductase family 1 member C3 (AKR1C3) is induced by insulin in PCOS adipocytes and is the predominant enzyme for potent androgen formation causing ligand-dependent androgen receptor (AR) activation. AR induces fatty acid synthase (FASN), a central enzyme for de novo lipogenesis. To investigate how insulin signaling induces AKR1C3 to promote lipid overload through induction of FASN, we used differentiated human Simpson–Golabi–Behmel syndrome adipocytes as a model for PCOS adipocytes. Induction of AKR1C3 and FASN was shown to be dependent on phosphoinositide 3-kinase/protein kinase B/ mammalian target of rapamycin/nuclear factor-erythroid 2-related factor 2 using pharmacological and genetic manipulation. FASN induction was shown to be AKR1C3 and AR dependent. Monofunctional AKR1C3 inhibitors, which competitively inhibit AKR1C3, did not block FASN induction, whereas bifunctional inhibitors, which competitively inhibit AKR1C3 and attenuate AR signaling by increasing AR degradation and ubiquitination, did suggesting a nonenzymatic role for AKR1C3 to stabilize AR. AKR1C3 and AR interacted as seen by co-immunoprecipitation, proximity ligation assay, and co-occupancy on FASN locus using chromatin immunoprecipitation–quantitative polymerase chain reaction assays in a ligand-dependent and ligand-independent manner. In the absence of androgens, bifunctional inhibitors prevented lipid droplet formation, whereas monofunctional inhibitors did not. We propose that AKR1C3 has 2 roles in PCOS: to catalyze potent androgen formation in adipocytes promoting hyperandrogenism and to induce FASN by stabilizing AR in the absence of androgens. AKR1C3 may be a therapeutic target for bifunctional inhibitors to reduce cardiometabolic disease in PCOS women.
The Early Portuguese Slave Ship and the Infrastructure of Racial Capitalism
Authors: More Anna
Published: February 2023

This article argues that an infrastructural analysis of the early Portuguese slave trade permits a detailed account of the emergence of what Cedric Robinson called “racial capitalism.” The early Portuguese slave ship is one of the clearest examples of how an infrastructure of accumulation accelerated the racialization of capitalism. As denounced by the 1684 Portuguese Law on Tonnage, the holds of the early slave ships created spatial regimes that regularly killed captives through asphyxiation, a unique form of death resulting from the reduction of human life to capital. If enslavement was defined by this spatial regime of suffocation, the early slave trade extended the grounds for racialization through extensive networks of credit and debt. This financial system established the parameters of enslavement and freedom, bridging shipboard and terrestrial social relations. Early slave ships included Black sailors, known as grumetes. A term that became adopted throughout the first region of the Portuguese slave trade in Africa, grumete referred to African wage laborers who worked with Luso-African traders. As wages were likely paid in credit that could only be cashed out by participating in the sale of humans, the freedom of the grumetes was constrained by the system of credit that financed the early trade. The infrastructure of the early slave trade was thus the nexus and conduit between interconnected financial modes, commodified life and debt, that together account for the racialization of the early Atlantic world.
Back on the Chain Gang
Authors: Zieger Susan
Published: February 2023

This essay explores the road and the chain as material and ideological forms of logistical and infrastructural power. Focusing on threechain gang narratives, John L. Spivak's Hard Times on a Southern Chain Gang (1932), Elliot Burns's I Am a Fugitive from a Georgia Chain (1932), and its film adaptation, I Am a Fugitive from a Chain Gang! (1932), the essay shows how these white-authored stories imagine the extraction of Black male labor in the construction of road infrastructure in the early twentieth-century southern United States. The essay demonstrates how logistics—the art and science of moving goods, people, and information efficiently to maximize profit—inheres in the infrastructures it calls into being. It traces the history of the chain gang through the shackles used to immobilize enslaved people on the ship, in the coffle, and on plantations, contending that such iron implements are infrastructure that helped build the nation. Chain gangs similarly relied on the forced labor of Black men who were routinely rounded up, incarcerated, and set to work on roads that tantalized them with the freedom of mobility while punishing them with backbreaking labor and physical torture. Chain gangs were a logistical phenomenon, the supply of labor at the right time and right place to maximize profit for private capital, which obtained this free labor through its collusion with the state. In this case study, the logistical aspect of infrastructure articulates it not as a promise of the common good, but as a threat against the disenfranchised whose freedom was abridged to make it.
Robot-Assisted Versus Laparoscopic Distal Pancreatectomy in Patients with Resectable Pancreatic Cancer: An International, Retrospective, Cohort Study
Authors: Chen Jeffrey W. , van Ramshorst Tess M. E. , Lof Sanne , Al-Sarireh Bilal , Bjornsson Bergthor , Boggi Ugo , Burdio Fernando , Butturini Giovanni , Casadei Riccardo , Coratti Andrea , D’Hondt Mathieu , Dokmak Safi , Edwin Bjørn , Esposito Alessandro , Fabre Jean M. , Ferrari Giovanni , Ftériche Fadhel S. , Fusai Giuseppe K. , Groot Koerkamp Bas , Hackert Thilo , Jah Asif , Jang Jin-Young , Kauffmann Emanuele F. , Keck Tobias , Manzoni Alberto , Marino Marco V. , Molenaar Quintus , Pando Elizabeth , Pessaux Patrick , Pietrabissa Andrea , Soonawalla Zahir , Sutcliffe Robert P. , Timmermann Lea , White Steven , Yip Vincent S. , Zerbi Alessandro , Abu Hilal Mohammad , Besselink Marc G. ,   For the European Consortium on Minimally Invasive Pancreatic Surgery (E-MIPS), Aussilhou Beatrice , Kamarajah Sivesh K. , van Laarhoven Stijn , Malinka Thomas , Marudanayagam Ravi , Ricci Claudio , Sánchez-Velázquez Patricia
Published: February 2023

Background

Robot-assisted distal pancreatectomy (RDP) is increasingly used as an alternative to laparoscopic distal pancreatectomy (LDP) in patients with resectable pancreatic cancer but comparative multicenter studies confirming the safety and efficacy of RDP are lacking.

Methods

An international, multicenter, retrospective, cohort study, including consecutive patients undergoing RDP and LDP for resectable pancreatic cancer in 33 experienced centers from 11 countries (2010–2019). The primary outcome was R0-resection. Secondary outcomes included lymph node yield, major complications, conversion rate, and overall survival.

Results

In total, 542 patients after minimally invasive distal pancreatectomy were included: 103 RDP (19%) and 439 LDP (81%). The R0-resection rate was comparable (75.7% RDP vs. 69.3% LDP, p = 0.404). RDP was associated with longer operative time (290 vs. 240 min, p < 0.001), more vascular resections (7.6% vs. 2.7%, p = 0.030), lower conversion rate (4.9% vs. 17.3%, p = 0.001), more major complications (26.2% vs. 16.3%, p = 0.019), improved lymph node yield (18 vs. 16, p = 0.021), and longer hospital stay (10 vs. 8 days, p = 0.001). The 90-day mortality (1.9% vs. 0.7%, p = 0.268) and overall survival (median 28 vs. 31 months, p = 0.599) did not differ significantly between RDP and LDP, respectively.

Conclusions

In selected patients with resectable pancreatic cancer, RDP and LDP provide a comparable R0-resection rate and overall survival in experienced centers. Although the lymph node yield and conversion rate appeared favorable after RDP, LDP was associated with shorter operating time, less major complications, and shorter hospital stay. The specific benefits associated with each approach should be confirmed by multicenter, randomized trials.
Το δραματικό πρόσωπο του Σωκράτη στο μεταίχμιο φιλοσοφίας και θεάτρου κατά τον 20ο και 21ο αιώνα
Authors: Σπυρίδης Ιωάννης
Published: February 2023

Στην παρούσα διατριβή εξετάζεται η διδασκαλία του Σωκράτη μέσα από το πρίσμα του δράματος και της φιλοσοφίας. Ο Σωκράτης αποτελεί την ιδανική περίπτωση στοχαστή όπου η έλλειψη γραπτού λόγου καθώς και η επιρροή που άσκησε επάνω σε πολλούς συγγραφείς και σχολές, τον κατατάσσουν σε ένα ερευνητικό πεδίο που δεν περιορίζεται μόνο σε μια επιστήμη. Το θέατρο και η φιλοσοφία ως αντιμαχόμενες πλευρές της ανθρώπινης έκφρασης κατά την περίοδο της αρχαιότητας βρίσκουν κοινό έδαφος στην περίπτωση του αναδεικνύοντας με αυτό τον τρόπο τις δυνατότητες που ενέχουν ως προς συνεργασία. Ο δραματικός Σωκράτης δραστηριοποιείται καλλιτεχνικά στο σήμερα έχοντας όμως την αφετηρία του στην φιλοσοφική διδασκαλία της αρχαιότητας. Σύγχρονοι μελετητές παρατηρούν την διαχρονικότητα του επαναφέροντας το σωκρατικό “γνῶθι σαὐτόν” στο προσκήνιο της ερευνητικής δραστηριότητας.
Fliperentiation: Η διαφοροποιημένη διδασκαλία στο πλαίσιο του μοντέλου της ανεστραμμένης τάξης
Authors: Σιδηροπούλου Ζωή , Μπότσογλου Καφένια , Πολίτη Βικτώρια
Published: February 2023

Οι σημερινές πολυπληθείς τάξεις αποτελούνται από ένα σύνολο μαθητών με διαφορετικές μαθησιακές ανάγκες, εμπειρίες και ικανότητες, σημαντικά χαρακτηριστικά τα οποία οι εκπαιδευτικοί καλούνται να συγκεράσουν προκειμένου να ασκήσουν αποτελεσματικά τα διδακτικά τους καθήκοντα. Η διαφοροποιημένη διδασκαλία είναι η μέθοδος που απαντά με τον καλύτερο τρόπο στο αίτημα για σεβασμό στις ιδιαιτερότητες κάθε μαθητή, καθώς αφορά στην οργανωτική και παιδαγωγική προσαρμογή της διδασκαλίας στις απαιτήσεις των σύγχρονων ανομοιογενών τάξεων. Ωστόσο, η εφαρμογή της στις σχολικές αίθουσες δεν είναι ιδιαιτέρως συχνή, εξαιτίας του περιορισμένου διδακτικού χρόνου για την κάλυψη του όγκου της διδακτέας ύλης και της δυσκολίας που συνεπάγεται η παράλληλη εργασία του εκπαιδευτικού προς τους μαθητές διαφορετικών επιπέδων. Η αναδυόμενη εκπαιδευτική προσέγγιση που συναντάται στη διεθνή βιβλιογραφία με τον όρο Fliperentiation (Flipped Learning and Differentiation) ενθαρρύνει τον διαφορετικό τρόπο οργάνωσης της εκπαιδευτικής διαδικασίας, καλύπτοντας τις ανάγκες της διαφοροποιημένης διδασκαλίας. Συνδυάζοντας το μοντέλο της ανεστραμμένης τάξης και τη μεθοδολογία της διαφοροποιημένης διδασκαλίας, συνδέεται με ευέλικτες εκπαιδευτικές προσεγγίσεις που προσφέρουν στον εκπαιδευτικό τον απαιτούμενο χρόνο προκειμένου να επικεντρωθεί στις ιδιαίτερες ανάγκες κάθε μαθητή και να προσαρμόσει τη διδασκαλία του σε αυτές. Το παρόν άρθρο παρουσιάζει μια ολοκληρωμένη σύνθεση των διαθέσιμων ερευνητικών δεδομένων σχετικά με την προσέγγιση του Fliperentiation, καθώς και τα αποτελέσματα προηγούμενων ερευνών σχετικά με τη δυνατότητα διαφοροποίησης της διδασκαλίας στο περιβάλλον της ανεστραμμένης τάξης. Τους βασικούς θεματικούς άξονες της βιβλιογραφικής ανασκόπησης αποτελούν η ενδυνάμωση των κινήτρων των μαθητών για ενεργητική συμμετοχή στη μαθησιακή διαδικασία, η καλλιέργεια των συνεργατικών τους δεξιοτήτων και η ανάπτυξη της αυτονομίας τους, μέσα από την εφαρμογή των μεθοδολογιών της ανεστραμμένης τάξης και της διαφοροποιημένης διδασκαλίας.
Analysis of financial statements
Authors: Sigidov Yuriy , Moroz Natal'ya , Oksanich Elena , Yasmenko Galina , Horuzhiy Lyudmila , Zonova Alevtina , Cheglakova Svetlana
Published: February 2023

The textbook shows the role of financial statements in the formation of information necessary for internal and external users interested in it. The requirements for financial statements are defined, the methodology of its analysis is described in detail on a concrete example, taking into account the achievements of modern economic science. The possibilities of using the results of the analysis for the preparation, justification and adoption of strategic and tactical management decisions at different levels are considered.
Meets the requirements of the federal state educational standards of higher education of the latest generation.
It is intended for students in the field of training 38.03.01 "Economics", practicing accountants, economists and students of the system of additional vocational education.
Literature of the Finno-Ugric peoples of Russia
Authors: Hayrullin Ruslan , Zayceva Tat'yana , Bakula Viktoriya , Katorova Aleksandra , Kondrat'eva Natal'ya , Kudryavceva Raisiya , Kuznecova Tat'yana , Limerov Pavel , Limerova Valentina , Mihaylov Vitaliy , Ostapova Elena , Rodionov Vitaliy , Hazankovich Yuliya , Biryukova Ol'ga
Published: February 2023

The textbook examines the development of Finno-Ugric literature in Russia from its inception to the present day. Materials are presented for the study of both survey topics, the purpose of which is to familiarize students with the literary process of a particular region, and monographic ones, introducing students to the work of the most prominent representatives of national literatures: K. Zhakov, K. Gerd, K. Abramov, Yu. Shestalov, V. Columbus and others.
Meets the requirements of the federal state educational standards of higher education of the latest generation.
It is intended for students studying undergraduate programs in the areas of 45.03.01 "Philology" and 44.03.01 "Pedagogical education" with the appropriate level of training, but can also be used at other levels of education, including master's and postgraduate studies in philological and pedagogical areas of training, as well as retraining of teachers of Russian and native languages and literatures.
Spin Cycle
Authors: Coppinger Rob
Published: February 2023

Aero-engine developers are seeking to squeeze the last drops of efficiency and increased power possible from compressor designs
The couple norm in single men’s digital stories
Authors: Kinnunen Anu , Pietilä Ilkka
Published: February 2023

The number of people living alone is increasing in Finland (OSF, 2020a; 2020b), in Europe (Eurostat, 2020a) and globally. Individualisation is growing, and many public institutions are adjusting to the rising number of single clientele. At the same time, the couple norm persists, and monogamous partnering is still often seen as the most appropriate way to organise intimate adult life. In this study, we analysed the written stories of 19 single men aged 29–64 and found that the couple norm was predominant in their stories. Internalisation of the norm caused feelings of inadequacy, a lack of self-appreciation and uncertainty about the future. Many men attributed their singlehood to events in their past and felt a lack of agency at present.
Nonlinear properties of organic single crystal waveguides: a review
Authors: Rush J.D. , Holdcroft G.E. , Dunn P.L.
Published: February 2023

Waveguides with organic single crystals as the guiding region are the subject of much worldwide attention. Our own interests lie primarily in the fabrication of organic crystal cored fibres although waveguides with channel, ridge or wedge type profiles are very attractive structures from which to fabricate optical nonlinear devices. In this paper we will review the present worldwide status of the art in organic single crystal growth in waveguiding structures and the current nonlinear results. We will also address the problems that have to be solved before working devices can be demonstrated.
Squeezed States, Parametric Interactions and Fundamental Noise Sources in Optical Fibers
Authors: Shelby R. M. , Levenson M. D.
Published: February 2023

Well-stabilized lasers emit radiation that is a close approximation to a coherent state: a classical mean field which varies sinusoidally in time at optical frequency ω0, superposed with broad-band noise fields due to the field's quantum uncertainty in its ground state (i.e. vacuum fluctuations). When detected by a standard photodetector, the interference between these vacuum fields and the coherent mean field causes the noise floor commonly referred to as the "shot-noise limit." The vacuum noise also causes fluctuations in the phase of the beam that are independent and uncorrelated with the amplitude fluctuations, and to which photodetectors are insensitive. The amplitude and phase fluctuations of the field can be represented by quadrature amplitudes

X
^

A

(
δ
)

and

X
^

ϕ

(
δ
)

which are the Fourier components of amplitude and phase modulation or fluctuation at a particular modulation frequency δ. These quadrature amplitudes are non-commuting quantum observables which obey the uncertainty principle.
Nonlinear Coupling of Planar Waveguide Modes Propagating in Different Directions
Authors: Weinert-Rączka Ewa
Published: February 2023

Theoretical possibility of nonlinear coupling between planar waveguide modes propagating in different directions is examined. The phenomenon consists in third-order nonlinear interaction between two guided modes (initial and generated) and two waves falling from outside on the waveguide surface. The propagation direction and intensity of the generated mode depend on the properties of the external waves. Therefore, the possibility of nonlinear, partially transparent mirror with regulated angle and reflectance, placed inside the waveguide slab appears.
Soliton Propagation over Very Long Distances: A New World of Experiment for Nonlinear Optics
Authors: Mollenauer L. F. , Smith K.
Published: February 2023

With a recirculating, unity gain fiber loop, we have been able to study soliton propagation over variable path lengths extending to many thousands of kilometers. This has made an entirely new range of effects accessible for study.
Problem of Noise Evolution in Nonlinear Fiber Systems Based on Optical Soliton Effects
Authors: Afanasjev V.V. , Dianov E.M. , Serkin V.N.
Published: February 2023

Progress in the experiments with optical solitons, creation of new types of lasers-soliton lasers, developing of the "soliton" fiber systems for the data storage and transmission gave rise to a number of new problems in the soliton theory. One of such new problems directly connected with the experiment is the analysis of statistical solutions for the nonlinear equations describing processes of optical soliton formation in fibers. In this paper we present the results on the statistical modelling of the nonlinear dynamics of optical solitons and optical noise in the fiber systems for the data storage and transmission.
Overview of Nonlinear Optical Guided-Wave Devices
Authors: Seaton C. T.
Published: February 2023

The characteristics of high power density created by moderate powers in small cross-sectional areas and diffractionless propagation over long interaction lengths make waveguides attractive for implementing efficient nonlinear optical devices. Integrated optical devices can be used in an all-optical mode by introducing waveguide media with intensity dependent refractive indices.
Optical Fiber Transmission Scheme with Ultra-High Bit-Rate Capability
Authors: Boyer G. R. , Franco M. A. , Jackson M. K. , Mysyrowicz A.
Published: February 2023

An optical fiber transmission scheme with 500 Gbit/s rate is demonstrated experimentally. Limitations of the system due to optical nonlinearities are observed and discussed.
Distortion of a broadband-intensity signal during its transmission through a chain of lumped amplifiers due to their saturation
Authors: Luchnikov A.V. , Pilipetskii A.N.
Published: February 2023

Experiments on soliton pulse transmission through optical fiber on the distance of up to 10000 km [1] confirm the possibility of realization of ultra long high-bit-rate soliton communication systems. At the present moment it seems most reliable to compensate the optical fiber losses with the help of lumped erbium-doped fiber amplifiers, periodically placed along all the transmission distance. As the value of the erbium fiber amplifier saturation power is not very high (~ 0.5 mW), than the influence of the amplifier saturation could affect on the signal transmission in the soliton regime [2]. The amplifier saturation in soliton communication systems could result in decreasing of the soliton sequence signal-noise ratio. This effect can be accumulated after transmission through a large number of amplifiers (> 300 for L ≈ 10000 km [1]).
A Digital Nonlinear Optical Loop Mirror Switch
Authors: Finlayson N. , Nayar B.K. , Doran N. J.
Published: February 2023

Ultrafast all-optical switching has been demonstrated in a number of silica fibre interferometric devices. In particular, the nonlinear optical loop mirror (NOLM), first fabricated by us, has been successfully used to demonstrate stable ultrafast multiplexing/de-multiplexing for high bit-rate optical fibre communication systems and for pulse shaping and pedestal supression. The switching power tends to be generally high due to the small nonlinearity of fused silica. However, the signal switching powers can now be reduced to the order of microwatts with the use of fibre amplifiers due to demonstrably stable operation of NOLMs with very long loop lengths (> 5 km). The NOLM exhibits a sinusoidal CW transmittance as a function of the input power. The development of an ultrafast digital optical switch for all-optical signal processing is attractive [1], requiring that the switching characteristics be sharper than sinusoidal. One approach to synthesizing a digital switching characteristic is to concatenate nonlinear fibre interferometric switching devices. In this paper we present the results of the first switching experiment involving two concatenated NOLMs. Digital switching characteristics are obtained. The device can also be used for generating nearly square pulses.
Nonlinear CDS Grating Coupler: C.W. and pulsed operation
Authors: Bertolotti M. , Michelotti F. , Nisio C. , Fazio E. , Assanto G. , Cali’ C.
Published: February 2023

Distributed couplers, such as prisms and gratings, have been largely employed in conjunction with nonlinear planar waveguides in order to study the nonlinear properties of the structures, suitable for all optical devices in integrated optics.
Numerical Study of Active Three-Waveguide Nonlinear Directional Coupler
Authors: Di Pasquale F. , Hernandez-Figueroa H.E. , Ettinger R.D. , Fernandez F.A. , Davies J.B.
Published: February 2023

Active and nonlinear waveguides have been investigated extensively in recent years, because of the possibility of performing all-optical signal processing in integrated optical circuits. Erbium-doped silica waveguides, in particular, can provide at the same time high gain [1],[2] and an intensity dependent refractive index with large nonlinear coefficient [3]. These features can improve the performance of all-optical switching devices [4] and suggest fascinating new operation conditions. In this paper, the behaviour of an active nonlinear three-slab directional coupler operating at 1.53μmis numerically investigated with a split-step finite-element method (SSFEM) [5], which allows accurate numerical simulations.
Clusterisation and contrast enhancement at light propagation in a cable of nonlinear coupled fibers
Authors: Firth W.J. , Samson B.A.
Published: February 2023

The problem of optical computing is under intensive consideration in recent years because optical schemes allow to produce parallel data processing as well to develop principles of associative optical memory.
Nonlinear waveguiding in polydiacetylene channel waveguides
Authors: Blau Werner
Published: February 2023

Summary not available at press time.
Advances In Organic Materials for and with Nonlinear Optics
Authors: Meredith Gerald R.
Published: February 2023

Molecular engineering of materials, which relies on the advanced art of organic chemistry and the facile assembly of molecular components, is reviewed. The behavior of molecular hyperpolarizability and correlations with other properties are illustrated. Examples of the discovery or creation of prospective NLO materials illustrate how the frontiers of materials science are often tested.
Semiorganic Nonlinear Optical Materials
Authors: Chang Tallis Y.
Published: February 2023

Summary not available at press time.
New Applications of Phase Conjugation in Imaging
Authors: Feinberg Jack
Published: February 2023

I will discuss some new directions for phase conjugation, including imaging through a scattering medium and locking laser-diode arrays.
Coherent Ultrafast All-Optical Switching in Fibers
Authors: Stegeman George I. , Krautschik Christof G. , Stolen Roger H.
Published: February 2023

All-optical switching reported to date in fibers or channel waveguides has relied on having a high intensity beam to either switch itself between two waveguides, or to switch a low intensity signal beam.[1] Since the switching mechanisms all rely on intensity, any information contained in the phase of a signal beam cannot be used. Here we propose and demonstrate experimentally for the first time a different approach in which a weak beam can switch a strong beam, with the fraction switched controlled by the phase instead of the intensity of the control beam. Picosecond switching based on this idea was implemented in rocking filter fibers.
Third-Order Optical Nonlinearities in C60 and C70-Toluene Solutions
Authors: Zhang Zhanxing , Wang Dadi , Ye Peixian , Li Yuliang , Wu Peiji , Zhu Daoben
Published: February 2023

C60 and C70 buckminsterfullerenes have attracted much attention in recent years because of their special structure. Recently, Blau et al[1] presented the first measurement of the third-order nonlinear susceptibility in C60-benzene solutions using 50-psec pulses at 1.064 μm. Here, we report our studies of the third-order optical nonlinearity in C60 and C70-toluene solutions using 30-psec pulses at 0.532 μm, which emphsize on the measurements of the tensor element

χ

1212

(
3
)

.
A new observation on optical phase conjugation using barium titanate: Dark hole effect
Authors: Jeon Hyung Wook , Son Jung Young , Lee Yim Kul , Um Yong Sik
Published: February 2023

New experimental observations on a dark hole obtained at the center of self-pumped phase conjugated image are presented. We focus on beam fanning and the relative position of the back focal plane of a Fourier transforming lens to the crystal (Sanders' barium titanate) used. A collimated argon-ion laser beam (514.5nm) with Gaussian profile illuminates a clear circular aperture as an input object and is focused into the crystal of 5mm × 4.8mm × 4.2mm (c axis) by the lens as shown in Fig. 1. When the center of the crystal is located behind the back focal plane of the lens, the optical phase conjugated image contains a dark hole at its center as shown in Fig. 2(a). As the center of the crystal moves away from the back focal plane, the size of the dark hole tends to decrease as shown in Fig. 2(b). No dark hole was obtained when the crystal was further moved backward as shown in Fig. 2(c). It is speculated that low spatial frequency components of the resulting Fourier pattern are suppressed by beam fanning inside the crystal and that the cutoff frequency decreases as the crystal moves backward.
Reversible optical storage effects in low molar mass chiral liquid crystals
Authors: Eichler H. J. , Elschner R. , Heppke G. , Macdonald R. , Schmid H.
Published: February 2023

In recent years laser adressing of liquid-crystalline polymers have been extensively studied owing to their suitability for optical information storage. However, many practical applications of polymers are somewhat limited because of their high viscosity, which can be several orders of magnitude larger than their low molar mass analogues [1]. Recently we report on the possibility to use low molar mass liquid crystals in optical information and data processing systems as holographic recording materials [2].
The Exploration of New Organic Crystals for Semiconductor Laser Second-Harmonic Generation
Authors: Jiang Min-hua , Tao Xu-tang , Yuan Duo-rong , Zhang Nan , Xu Dong
Published: February 2023

The demand for miniature blue and violet laser applications has stimulated the research on nonlinear optical crystals for semiconductor laser (800-1000nm) second-harmonic generation (SHG).This paper summarized our recent development on the exploration of new organic nonlinear optical (NLO) materials for such purposes. Based on the features of organic crystals and the requirements of semiconductor lasers to the corresponding SHG materials. The relations between the crystal sturcture and the spectral characteristics as well as the NLO properties of the organic corjugated molecules were investigated. The electron spectra of the donors and acceptors and their influence on the NLO properties were analyzed. According to these results. We have made an approach for solving the contradiction existed between the UV transmission range and the nonlinear conversion efficiency of the crystals i. e. Substituting the medium and weak donor-acceptor radicals into benzene- the organic conjugated matrix, to form benjene derivatives. Which may possess both large NLO coefficients and good UV transmission property, and satisfy the requirement for diode laser SHG applications.
Nonlinear Absorption Coefficient of C60 and Metal-Free Phthalocyanine at 1064 nm
Authors: Lindle J. R. , Shirk J. S. , Flom S. R. , Kafafi Z. H. , Pong R. G. S. , Bartoli F. J.
Published: February 2023

Recent degenerate-four wave mixing (DFWM) studies, performed on C60 [1] and phthalocyanines (Pc) [2] at 1064 nm have shown that these materials possess large optical nonlinearities. The highly delocalized π-electron system within these materials is believed to contribute significantly to the observed nonlinear optical response. In addition, it has been shown in the case of the phthalocyanines that the introduction or modification of low lying electronic states by metal substitution can enhance the optical nonlinearity. There is also evidence that optical pumping to long-lived excited states [2] contributes significantly to the nonlinear response in some of the phthalocyanines. Two photon excitation of these electronic states may also occur. It is the purpose of this paper to investigate the contribution that optical pumping and nonlinear absorption make to the nonlinear response of the material.
Asymmetric susceptibilities arising from frequency dependent dephasing time in Quantum Well materials
Authors: Spencer P.S. , Shore K.A.
Published: February 2023

The search for novel optical devices has recently led to the investigation of the optical properties of inter-subband transitions in Quantum well structures.
Photorefractive fixing method for the determination of H concentration in LiNbO3
Authors: Müller R. , Arizmendi L. , Carrascosa M. , Cabrera J.M.
Published: February 2023

Hydrogen is an important impurity in LiNbO3. During the crystal growth it enters the lattice, mostly in the form of OH- ions [1]. In photorefractive LiNbO3 it is generally accepted that protons are the main mobile ionic entities giving rise to fixed volume holograms. The electronic space charge field which, via the electro-optic effect causes a refractive index modulation, induces proton migration above room temperature (140°C), well below the temperature at which electron thermal detrapping starts (> 180°C). The refractive index pattern arising from the proton space charge field can not be erased by illumination anymore, thus it is called a fixed pattern.
Modal Growth of SHG in Doped Silica Thin Film Waveguides
Authors: White W. Roc , Kester John J. , Pribyl Skip C.
Published: February 2023

Frequency doubling of 1064 nm laser light is observed in Ge-doped SiO2 thin film waveguides. SHG growth is examined as a function of input polarization and waveguiding modes.
Anisotropic Two-Photon Transition in GaAs/AlGaAs Multiple Quantum Well Waveguides
Authors: Yang C. C. , Villeneuve A. , Stegeman G. I. , Lin Cheng-Hui , Lin Hao-Hsiung
Published: February 2023

Two-photon transitions near the absorption edge in a multiple quantum well (MQW) structure are important because, on one hand, they provide information about the energy states involved in the forbidden direct transitions1 and, on the other hand, the induced Kerr-like optical nonlinearity has potential for ultrafast nonlinear switching applications2. In this paper, we report the first direct measurements of the two-photon absorption coefficient β2 and nonlinear refractive-index n2 in GaAs/AlGaAs MQW channel waveguides from 1490 to 1660 nm. We observed significant differences between TE and TM modes for both β2 and n2.
Measurements of light-scattering noise during two-wave maxing in a Kerr medium
Authors: Pizzoferrato R. , Zammit U. , Marinelli M. , McGraw R. , Rogovin D.
Published: February 2023

Measurements of light-scattering noise during two-wave mixing in a Kerr medium are reported. Excellent agreement with theory is obtained using the stochastic noise model.