Multi-nucleon transfer in 58Ni+60Ni{}^{58}\text{Ni}+{}^{60}\text{Ni} and 60Ni+60Ni{}^{60} \text{Ni}+{}^{60}\text{Ni} in stochastic mean-field approach

The multi-nucleon exchange mechanism in ${}^{58} \text{Ni}+{}^{60} \text{Ni}$ and ${}^{60} \text{Ni}+{}^{60}\text{Ni}$ collisions is analyzed in the framework of the stochastic mean-field approach. The results of calculations are compared with the TDRPA calculations and the recent data of ${}^{58} \text{Ni}+{}^{60} \text{Ni}$. A good description of the data and a relatively good agreement with the TDRPA calculations are found.Comment: 6 pages, 6 figure

Ağır-iyon reaksiyonlarının stokastik ortalama-alan kuramı çerçevesinde incelenmesi

TÜBİTAK MFAG15.10.2015Bu projede, ağır-iyon derin-inelastik çarpışmalarında mermi ve hedef çekirdekler arasında nükleon alış-verişi ile ilgili transport katsayıları için stokastik ortalama- alan kuramı (SOA) çerçevesinde yarı-klasik ve hafıza etkilerini içeren kuantal hesaplamalar yapıldı. Simetrik ve proton/nötron bakımından asimetrik sistemlerin füzyon potansiyel bariyer değerlerinin hemen altındaki enerjilerde merkezi ve merkezi olmayan çarpışmaları göz önüne alındı. Ağır-iyonların merkezi çarpışmaları için türetilen ve simetrik sistemlerde test edilen kuantum mekaniksel hesaplar, asimetrik sistemlere ve merkezi olmayan çarpışmalara genişletildi. Benzer şekilde, nükleon alışveriş difüzyon katsayısının analitik ifadeleri, simetrik ve asimetrik ağır-iyonların merkezcil olmayan çarpışmaları için hafıza etkilerini de içerecek şekilde kuantum mekaniksel olarak türetildi. Proje kapsamında, ağır-iyon derin-inelastik çarpışma sonrası ayrışan çekirdeklerin proton ve nötron difüzyon katsayıları, kütle dağılımlarının varyansları ile toplam difüzyon katsayısı ve toplam nükleon kütle dağılımının varyansı çeşitli sistemler için hesaplandı. Proje iş paketlerinde öngörülen ve aşağıdaki verilen tüm çalışmalar tamamlandı. 1) Simetrik ve nötron/proton bakımından asimetrik atom çekirdeklerinin düşük- enerjili derin-inelastik merkezcil transport katsayılarının kuantal olarak hesaplanması ve daha önce yapılan yarı-klasik hesaplarla karşılaştırılması yapıldı. 2) Simetrik ve asimetrik atom çekirdeklerinin düşük-enerjili derin-inelastik merkezcil olmayan çarpışmalarında toplu değişkenlerin tanımlanması için gerekli olan pencere dinamığının zamana bağlı Hartree-Fock programına gerekli eklemeler yapılarak, proton ve nötron alış-verişi ile ilgili difüzyon katsayılarının kuantal olarak hesaplanması, bu katsayıları kullanarak ayrışan çekirdeklerin proton ve nötron dağılımlarının ortalama değerlerinin ve varyanslarının hesaplanması yapıldı. 3) Simetrik ve nötron/proton bakımından asimetrik atom çekirdeklerinin düşük- enerjili derin-inelastik merkezcil olmayan çarpışmalarında nükleon alış- verişine dayalı transport katsayılarının kuantal olarak hesaplanması, enerji disipasyon ve salınım mekanizmasının incelenmesi yapıldı. 4) Ağır çekirdekler arası nükleon transferi için transport katsayılarının hafıza etkilerini yaklaşık olarak hesaba katarak kuantal hesaplanması için yeni bir yöntem geliştirildi. 5) Yarı-fisyon reaksiyonlarının difüzyon menizmasıyla incelenmesi hesapları yapıldı

Future of nuclear fission theory

There has been much recent interest in nuclear fission, due in part to a new appreciation of its relevance to astrophysics, stability of superheavy elements, and fundamental theory of neutrino interactions. At the same time, there have been important developments on a conceptual and computational level for the theory. The promising new theoretical avenues were the subject of a workshop held at the University of York in October 2019; this report summarises its findings and recommendations.Peer reviewe

Future of nuclear fission theory

There has been much recent interest in nuclear fission, due in part to a new appreciation of its relevance to astrophysics, stability of superheavy elements, and fundamental theory of neutrino interactions. At the same time, there have been important developments on a conceptual and computational level for the theory. The promising new theoretical avenues were the subject of a workshop held at the University of York in October 2019; this report summarises its findings and recommendations

Elective Cancer Surgery in COVID-19-Free Surgical Pathways During the SARS-CoV-2 Pandemic: An International, Multicenter, Comparative Cohort Study.

PURPOSE: As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19-free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS: This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19-free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS: Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19-free surgical pathways. Patients who underwent surgery within COVID-19-free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19-free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score-matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19-free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION: Within available resources, dedicated COVID-19-free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

Elective cancer surgery in COVID-19-free surgical pathways during the SARS-CoV-2 pandemic: An international, multicenter, comparative cohort study

PURPOSE As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19–free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19–free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19–free surgical pathways. Patients who underwent surgery within COVID-19–free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19–free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score–matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19–free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION Within available resources, dedicated COVID-19–free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks