Bubbles as tracers of heat input to cooling flows

We examine the distribution of injected energy in three-dimensional, adaptive-grid simulations of the heating of cooling flows. We show that less than 10 percent of the injected energy goes into bubbles. Consequently, the energy input from the nucleus is underestimated by a factor of order 6 when it is taken to be given by PVgamma/(gamma-1), where P and V are the pressure and volume of the bubble, and gamma the ratio of principal specific heats.Comment: Accepted for publication in MNRAS; 5 page

DSDV, DYMO, OLSR: Link Duration and Path Stability

In this paper, we evaluate and compare the impact of link duration and path stability of routing protocols; Destination Sequence Distance vector (DSDV), Dynamic MANET On- Demand (DYMO) and Optimized Link State Routing (OLSR) at different number of connections and node density. In order to improve the efficiency of selected protocols; we enhance DYMO and OLSR. Simulation and comparison of both default and enhanced routing protocols is carried out under the performance parameters; Packet Delivery Ratio (PDR), Average End-to End Delay (AE2ED) and Normalized Routing Overhead (NRO). From the results, we observe that DYMO performs better than DSDV, MOD-OLSR and OLSR in terms of PDR, AE2ED, link duration and path stability at the cost of high value of NRO

Analysis and Modeling Experiment Performance Parameters of Routing Protocols in MANETs and VANETs

In this paper, a framework for experimental parameters in which Packet Delivery Ratio (PDR), effect of link duration over End-to-End Delay (E2ED) and Normalized Routing Overhead (NRO) in terms of control packets is analyzed and modeled for Mobile Ad-Hoc NETworks (MANETs) and Vehicular Ad-Hoc NETworks (VANETs) with the assumption that nodes (vehicles) are sparsely moving in two different road. Moreover, this paper contributes the performance comparison of one Proactive Routing Protocol; Destination Sequenced Distance vector (DSDV) and two reactive protocols; DYnamic Source Routing (DSR) and DYnamic MANET On-Demand (DYMO). A novel contribution of this work is enhancements in default versions of selected routing protocols. Three performance parameters; PDR, E2ED and NRO with varying scalabilities are measured to analyze the performance of selected routing protocols with their original and enhanced versions. From extensive simulations, it is observed that DSR outperforms among all three protocols at the cost of delay. NS-2 simulator is used for simulation with TwoRayGround propagation model to evaluate analytical results

When Do Prompting and Prefix-Tuning Work? A Theory of Capabilities and Limitations

Context-based fine-tuning methods, including prompting, in-context learning, soft prompting (also known as prompt tuning), and prefix-tuning, have gained popularity due to their ability to often match the performance of full fine-tuning with a fraction of the parameters. Despite their empirical successes, there is little theoretical understanding of how these techniques influence the internal computation of the model and their expressiveness limitations. We show that despite the continuous embedding space being more expressive than the discrete token space, soft-prompting and prefix-tuning are strictly less expressive than full fine-tuning, even with the same number of learnable parameters. Concretely, context-based fine-tuning cannot change the relative attention pattern over the content and can only bias the outputs of an attention layer in a fixed direction. This suggests that while techniques like prompting, in-context learning, soft prompting, and prefix-tuning can effectively elicit skills present in the pretrained model, they cannot learn novel tasks that require new attention patterns

Density Functional Theory Study of Selenium-Substituted Low-Bandgap Donor-Acceptor-Donor Polymer

This is the author accepted manuscript. The final version is available from American Chemical Society via the DOI in this recordTheoretical study of an optically transparent, near-infrared-absorbing low energy gap conjugated polymer, donor-acceptor-donor (D-A-D), 2,1,3-benzosele-nadiazole (A) as acceptor and 3,4-ethylenedioxyselenophene (D) as donor fragments, with promising attributes for photovoltaic application is reported herein. The D and A moiety on the polymeric backbone has been found to be responsible for tuning the band gap, optical gap, open circuit (VOC), and short-circuit current density (JSC) in the polymers solar cells. D-A-D has a key role in charge separation and molecular architecture which ultimately influences the charge transport. Reduction in the band gap, high charge transformation, and enhanced visible light absorption in the D-A-D system is because of strong overlapping of molecular orbitals of D and A. The polaron and bipolaron effects are also investigated which has a direct relation with visible light photocurrent generation. In addition, the enhanced planarity and weak steric hindrance between adjacent units of D-A-D resulted in red-shifting of its onset of absorption. The simulated band gap of the D-A-D has excellent correlation with experimentally reported values for closely related systems, which validates the level of theory used. Finally, PSC properties of the designed D-A-D was modeled in the bulk heterojunction solar cell, which gives a theoretical VOC of about 1.02 eV. (Graph Presented)

Donor-acceptor polymer for the design of All-Solid-State dye-sensitized solar cells

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordDensity functional theory study has been carried out to design a new All-Solid-State dye-sensitized solar cell (SDSC), by applying a donor-acceptor conjugated polymer instead of liquid electrolyte. The typical redox mediator (I1−/I3−) is replaced with a narrow band gap, hole transporting material (HTM). The electronic and optical properties predict that donor and acceptor moieties in the polymeric body have increased the visible light absorption and charge transporting ability, compared to their parent polymers. A unique “upstairs” like band energy diagram is created by packing N3 between HTM and TiO2. Upon light irradiation on the proposed configuration, electrons will move from the dye to TiO2 and from HTM to dye (to regenerate dye), simultaneously. Our theoretical simulations prove that the proposed configuration will be highly efficient as the HOMO level of HTM is 1.19 eV above the HOMO of sanitizer (dye); providing an efficient pathway for charge transfer. High short-circuit current density and power conversion efficiency is promised from the strong overlapping of molecular orbitals of HTM and sensitizer. A low reorganization energy of 0.21 eV and exciton binding energy of 0.55 eV, confirm the high efficiency of HTM. Finally, a theoretical open-circuit voltage of 1.49 eV would results high quantum yield while, the chemical stability of HTM towards oxidation can be estimated from its high ionization potential value (4.57 eV)

The factors influencing cesarean-section rates-A narrative review from Pakistan

The significant increase in the rate of cesarean section is a major public health issue. The World Health Organization recommends C-section rates not to be greater than 10% and not lower than 5% as both the indicated limits can adversely affect maternal and newborn health. The rate of C-section deliveries is 22% according to recent Pakistan demographics and Health Survey of 2017-2018. This study contributes to the existing literature by examining the factors influencing high C-section rates in Pakistan. A narrative review of published literature between 2000 to 2020, on “factors influencing C-section rates in Pakistan” was done. The findings highlighted five factors that primarily influence utilization of C-section which include: 1. Accessibility to utilize C-section, 2. Association of C-section rates with socioeconomic profile, 3. Elective C-section, 4. Medical conditions as a cause of C-section, 5. C-section as a source of business. Pakistan like other Low middle income countries (LMICs) is facing the increased disease burden on its week and fragile health system. The over utilization of C-section rates has imposed additional burden on the health care system of Pakistan as well as increased economic and health resource liability on maternal care

Investigating the perceived effectiveness of Eye Movement Desensitisation Reprocessing (EMDR) treatment in adult survivors of childhood sexual abuse and the impact on neuropsychological, emotional and behavioural functioning and quality of life : a case series analysis

Childhood sexual abuse (CSA) is an ongoing issue (WHO, 2017) with 1 in 20children annually reported as being abused in the UK (NSPCC, 2019; Radford et al,2011). Many child survivors are of adolescent or young adult age before they requesthelp from relevant services (HAVOCA, 2021; NSPCC, 2018; Noel, Dogaru, and Ellis,2015; Flatley, 2017). The aim of this study was to investigate the perceivedexperiences of six young adult female survivors of CSA of their EMDR treatment aswell as an assessment of the changes in the individual trauma stress response. Thiscase series analysis explored (a) neuropsychological, emotional (namely low selfesteem, anxiety and depression), behavioural functioning and quality of life issuesusing descriptive statistics via outcome measures conducted before, during and aftertreatment and (b) client perspectives through qualitative interviewing at one-monthfollow-up to ensure adequate time was allowed to monitor changes using ThematicAnalysis [TA]. The study setting was within the Improving Access to PsychologicalTherapies (IAPT) program framework, established to ensure service users accessingNHS treatment are presented with choice in their treatment.The triangulation of data in this study allowed for a deeper analysis of theexperiences of adult CSA survivors undergoing EMDR treatment beyond anexamination of differences in pre and post outcome measures. The descriptivestatistics suggested overall positive changes in participant functioning in allmeasured domains (three positive, two moderate outcome cases and one scepticalno-improvement case; based on independent research rater feedback) howevervariable differences in neuropsychological processing from pre- to post-treatment.The descriptive statistics were limited in their generalisability because of certainlimitations in data collection as inhibited by COVID-19 restrictions and because ofthe small sample size. Three key themes were identified in the qualitative analysiswhich contributed to the literature on treatment of adult CSA survivors by identifyingwhich factors the clients identified as helpful and unhelpful to their treatment. Thesethemes were identified as being an ‘Unhelpful’ process (service time restrictions, fearof the lack of confidentiality, fear of emotional reprocessing), ‘Helpful’ aspects oftherapy (client choice in treatment, therapist interpersonal and professional skills,psychological resourcing, idiosyncratic approaches) and ‘Mixed Responses’ due to COVID-19 (face-to-face vs remote working). Overall, this study contributed to theliterature about EMDR treatment for adult CSA survivors by shedding insight into theperceived experiences of clients and providing further evidence for the efficacy ofthis treatment.Importantly, further research could investigate a potentially larger sample, emphasison neuropsychological functioning, and within differing settings, to understanddeficits within the current study. A qualitative study of the perceptions andexperiences of childhood sexual abuse survivors who opt for CBT over EMDR mightlead to recommendations for changes in protocol that would make EMDR moreacceptable. There is scope to further investigate EMDR as a reliable and validtreatment option within NHS IAPT settings, alongside essential service developmentin therapist training programmes to support the growing need for treatment ofmultiple-trauma and/or Complex-PTSD (ICD-11, International Classification ofDiseases-11, 2018)

Electronic properties of Β-TaON and its surfaces for solar water splitting

This is the final version of the article. Available from Elsevier via the DOI in this record.Recently, oxynitrides materials such as β-TaON has been using as a photoanode material in the field of photocatalysis and is found to be promising due to its suitable band gap and charge carrier mobility. Computational study of the crystalline β-TaON in the form of primitive unit cell, supercell and its N, Ta, and O terminated surfaces are carried out with the help of periodic density functional theory (DFT). Optical and electronic properties of all these different species are simulated, which predict TaON as the best candidate for photocatalytic water splitting contrast to their Ta 2 O 5 and Ta 3 N 5 counterparts. The calculated bandgap, valence band, and conduction band edge positions predict that β-TaON should be an efficient photoanodic material. The valence band is made up of N 2p orbitals with a minor contribution from O 2p, while the conduction band is made up of Ta 5d. Turning to thin films, the valence band maximum; VBM (−6.4 eV vs. vacuum) and the conduction band minimum; CBM (−3.3 eV vs. vacuum) of (010)-O terminated surface are respectively well below and above the redox potentials of water as required for photocatalysis. Charge carriers have smaller effective masses than in the (001)-N terminated film (VBM −5.8 and CBM −3.7 eV vs. vacuum). However, due to wide band gap (3.0 eV) of (010)-O terminated surface, it cannot absorb visible wavelengths. On the other hand, the (001)-N terminated TaON thin film has a smaller band gap in the visible region (2.1 eV) but the bands are not aligned to the redox potential of water. Possibly a mixed phase material would produce an efficient photoanode for solar water splitting, where one phase performs the oxidation and the other reduction.We acknowledge the financial support of Engineering and Physical Science Research Council, UK (EPSRC)under the research grant Nos. EP/P510956/1, EP/P003435/1 and EP/R512801/1. S.K acknowledges the Notur Norwegian supercomputing facilities through project nn4608k and the HyMatSiRen project 272806 by the Research Council of Norway. We also acknowledge Prof. Neil Allan and Dr. Sergio C. Espindola for their help in completing this work