bluuebunny/crossref_metadata_2025_split huggingface dataset:
An improved backward/forward sweep power flow method based on network tree depth for radial distribution systems
Authors: Kawambwa Shamte , Mwifunyi Rukia , Mnyanghwalo Daudi , Hamisi Ndyetabura , Kalinga Ellen , Mvungi Nerey 
Published: March 2021

AbstractThis paper presents an improved load flow technique for a modern distribution system. The proposed load flow technique is derived from the concept of the conventional backward/forward sweep technique. The proposed technique uses linear equations based on Kirchhoff’s laws without involving matrix multiplication. The method can accommodate changes in network structure reconfiguration by involving the parent–children relationship between nodes to avoid complex renumbering of branches and nodes. The IEEE 15 bus, IEEE 33 bus and IEEE 69 bus systems were used for testing the efficacy of the proposed technique. The meshed IEEE 15 bus system was used to demonstrate the efficacy of the proposed technique under network reconfiguration scenarios. The proposed method was compared with other load flow approaches, including CIM, BFS and DLF. The results revealed that the proposed method could provide similar power flow solutions with the added advantage that it can work well under network reconfiguration without performing node renumbering, not covered by others. The proposed technique was then applied in Tanzania electric secondary distribution network and performed well.
Toward Personalized Radiation Therapy of Liver Metastasis: Importance of Serial Blood Biomarkers
Authors: Ajdari Ali , Xie Yunhe , Richter Christian , Niyazi Maximilian , Duda Dan G. , Hong Theodore S. , Bortfeld Thomas 
Published: March 2021

PURPOSETo assess the added value of serial blood biomarkers in liver metastasis stereotactic body radiation therapy (SBRT).MATERIALS AND METHODSEighty-nine patients were retrospectively included. Pre- and midtreatment blood samples were analyzed for potential biomarkers of the treatment response. Three biomarker classes were studied: gene mutation status, complete blood count, and inflammatory cytokine concentration in plasma. One-year local failure (LF) and 2-year overall survival (OS) were chosen as study end points. Multivariate logistic regression was used for response prediction. Added predictive benefit was assessed by quantifying the difference between the predictive performance of a baseline model (clinicopathologic and dosimetric predictors) and that of the biomarker-enhanced model, using three metrics: (1) likelihood ratio, (2) predictive variance, and (3) area under the receiver operating characteristic curve (AUC).RESULTSThe most important predictors of LF were mutation in KRAS gene (hazard ratio [HR] = 2.92, 95% CI, [1.17 to 7.28], P = .02) and baseline and midtreatment concentration of plasma interleukin-6 (HR = 1.15 [1.04 to 1.26] and 1.06 [1.01 to 1.13], P = .01). Absolute lymphocyte count and platelet-to-lymphocyte ratio at baseline as well as neutrophil-to-lymphocyte ratio at baseline and before fraction 3 (HR = 1.33 [1.16 to 1.51] and 1.19 [1.09 to 1.30]) had the most significant association with OS ( P = .0003). Addition of baseline GEN and inflammatory plasma cytokine biomarkers in predicting LF, respectively, increased AUC by 0.06 (from 0.73 to 0.79) and 0.07 (from 0.77 to 0.84). In predicting OS, inclusion of midtreatment complete blood count biomarkers increased AUC from 0.72 to 0.80, along with significant boosts in likelihood ratio and predictive variance.CONCLUSIONInclusion of serial blood biomarkers leads to significant gain in predicting response to liver metastasis stereotactic body radiation therapy and can guide treatment personalization.
Formation of the Vocational-Oriented Environment of the School: from the Experience of the Work of the School of Moscow Region
Authors: Nechaev Mikhail , Frolova Svetlana 
Published: March 2021

Global changes taking place in all spheres of life have influenced the education sector. The school must prepare a graduate who can successfully socialize and be in demand and competitive. That is why the problem of professional self-determination and choice of a future profession by students is especially acute.
According to the authors of the article, one of the most important conditions for the successful professional self-determination of students is the vocational guidance environment of the school. The authors give a definition of the concept of "vocational guidance environment". They describe the stages of its formation, and also present the experience of creating a career guidance environment in one of the schools in the Moscow region.
The material of the authors can be useful for creating a career guidance environment, early career guidance and pre-professional training of students in educational organizations, which will ensure the emergence of a "new type" graduate - a young person who has the ability to consciously choose a professional path in unity with professional mobility.
A Theory of Statistical Inference for Ensuring the Robustness of Scientific Results
Authors: Coker Beau , Rudin Cynthia , King Gary 
Published: March 2021

Inference is the process of using facts we know to learn about facts we do not know. A theory of inference gives assumptions necessary to get from the former to the latter, along with a definition for and summary of the resulting uncertainty. Any one theory of inference is neither right nor wrong but merely an axiom that may or may not be useful. Each of the many diverse theories of inference can be valuable for certain applications. However, no existing theory of inference addresses the tendency to choose, from the range of plausible data analysis specifications consistent with prior evidence, those that inadvertently favor one’s own hypotheses. Because the biases from these choices are a growing concern across scientific fields, and in a sense the reason the scientific community was invented in the first place, we introduce a new theory of inference designed to address this critical problem. We introduce hacking intervals, which are the range of a summary statistic one may obtain given a class of possible endogenous manipulations of the data. Hacking intervals require no appeal to hypothetical data sets drawn from imaginary superpopulations. A scientific result with a small hacking interval is more robust to researcher manipulation than one with a larger interval and is often easier to interpret than a classical confidence interval. Some versions of hacking intervals turn out to be equivalent to classical confidence intervals, which means they may also provide a more intuitive and potentially more useful interpretation of classical confidence intervals. This paper was accepted by J. George Shanthikumar, big data analytics.
Comment on “Optimal Contract to Induce Continued Effort”
Authors: Cao Ping , Tian Feng , Sun Peng 
Published: March 2021

In this comment, we first use a counterexample to demonstrate that the optimal contract structure proposed in section 4 of the paper [Sun P, Tian F (2018) Optimal contract to induce continued effort. Management Sci. 64(9):4193–4217] can be wrong when the two players’ discount rates are different. We then specify correct optimal contract structures, which involve generalizing the contract space to allow random termination. Numerical study with a wide range of model parameters illustrates that such a random termination only occurs sparingly in optimal contracts. Moreover, the suboptimality gap, measured by the relative improvement of the optimal contract over the best contract without random termination, is extremely small. This paper was accepted by Manel Baucells, decision analysis.
Streptococcus equiinfections: current best practice in the diagnosis and management of ‘strangles’
Authors: Rendle David , de Brauwere Nic , Hallowell Gayle , Ivens Philip , McGlennon Abigail , Newton Richard , White Jo , Waller Andrew 
Published: March 2021

ForewordThis document was commissioned to provide UK veterinary surgeons with up-to-date information on Streptococcus equi infection and to provide practical recommendations for veterinary surgeons in the field. The participants were selected to provide representation from a range of expertise and viewpoints and included practitioners, academics and social scientists. The document and practical recommendations were developed using a modified non-anonymised two-round Delphi process, considering published and unpublished research relating to ‘strangles’ using online discussion. The expert group was convened by UK-Vet Equine and Redwings and an online meeting held on 20th January 2021 with sponsorship from MSD and support from World Horse Welfare. The sponsors did not participate in the meeting and had no influence over editorial content. Each of the panellists was provided with a sub-topic and presented a review of the evidence pertaining to that area prior to taking two rounds of questions relating to the evidence presented. Where research evidence was conflicting or absent, collective expert opinion, based on the experience of the group, was applied. The opinions expressed are the consensus of views expressed by the authors who all approved the final manuscript. Where it was not possible to reach consensus, different viewpoints are presented.
Methane leak detection by tunable laser spectroscopy and mid-infrared
imaging
Authors: Strahl Thomas , Herbst Johannes , Lambrecht Armin , Maier Eric , Steinebrunner Jonas , Wöllenstein Jürgen 
Published: March 2021

Tunable laser spectroscopy (TLS) combined with mid-infrared imaging is a powerful tool for a sensitive and quantitative visualization of gas leaks. This work deals with standoff methane leak detection within 2 m by an interband cascade laser (3270 nm wavelength) and an infrared camera. The concept demonstrates visualization of methane leakage rates down to 2 ml/min by images and sequences at frame rates up to 125 Hz. The gas plume and leak can be localized and quantified within a single image by direct absorption spectroscopy (DAS). The HITRAN database allows a calibration-free, pixelwise determination of the concentration in ppm*m. The active optical imaging concept showed pixelwise sensitivities around 1 ppm*m.
Optical design and intensity interferometry simulations in support of the Kilometer Space Telescope
Authors: Johnson Tim P. , Crowe Devon G. 
Published: March 2021

Very large telescopes will be needed for the future of space science, space laser-com, and other interstellar or interplanetary applications. However, as telescopes’ diameters increase, their weight and cost increase dramatically. An approximation for ground-based observatories is that their cost increases to the power of 2.7 of its diameter [SAO, Special Report #385 (1979), p. 9]. Large space-based telescopes become limited by the rocket size and power. Multiple telescopes are also needed for very long baseline interferometry (VLBI), which further increases cost. A solution to overcome these issues is the use of inflatable telescopes. A thin mirror material clearly has much lower mass; however, controlling its surface error or wavefront can be a challenge. Intensity interferometry is an imaging method that has a much looser sensitivity to wavefront error (WFE), and thus is an ideal match for very large inflatable telescopes. A spherical inflatable mirror is the most practical; however, it suffers from spherical aberration. This paper presents new optical designs and simulations for intensity interferometry in support of large inflatable spherical telescopes. The optical system design includes a novel five-mirror off-axis, free-form, spherical aberration corrector. The system design shown is a 10 m diameter f/1 spherical primary mirror with 1.2 arcmin (0.02°) field of view (FOV). MATLAB simulations of intensity interferometry combine signal with noise and WFE. Visibility-based VLBI image simulations are shown based on various telescope arrays. Simulations show that with a 1 GHz detector, a 1 cm RMS WFE is tolerable. So the challenge of the optical design is then more about gathering and concentrating the light down to a reasonable size detector. Further simulations of signal combined with noise indicate that the signal rate must be about 100 times higher than the noise rate for an adequate intensity interferometry measurement. Visibility-based image simulations reveal that many telescopes (5–20 per axis) are needed in a 2D array out to the first visibility minimum to adequately resolve unknown features of a distant object.
Power control strategies and network performance assessment for
C+L+S multiband optical transport
Authors: Correia Bruno , Sadeghi Rasoul , Virgillito Emanuele , Napoli Antonio , Costa Nelson , Pedro João , Curri Vittorio 
Published: March 2021

Spatial-division multiplexing (SDM) and band-division multiplexing
(BDM) have emerged as solutions to expand the capacity of existing
C-band wavelength-division multiplexing (WDM) optical systems and to
deal with increasing traffic demands. An important difference between
these two approaches is that BDM solutions enable data transmission
over unused spectral bands of already-deployed optical fibers, whereas
SDM solutions require the availability of additional fibers to
replicate C-band WDM transmission. On the other hand, to properly
design a multiband optical line system (OLS), the following fiber
propagation effects have been taken into account in the analysis:
(i) stimulated Raman scattering (SRS), which induces considerable
power transfer among bands; (ii) frequency dependence of fiber
parameters such as attenuation, dispersion, and nonlinear
coefficients; and (iii) utilization of optical amplifiers with
different doping materials, thus leading to different characteristics,
e.g., in terms of noise figures. This work follows a two-step
approach: First, we aim at maximizing and flattening the quality of
transmission (QoT) when adding L- and

-bands to a traditional WDM OLS where
only the C-band is deployed. This is achieved by
applying a multiband optimized optical power control for BDM upgrades,
which consists of setting a pre-tilt and power offset in the line
amplifiers, thus achieving a considerable increase in QoT, both in
average value and flatness. Second, the SDM approach is used as a
benchmark for the BDM approach by assessing network performance on
three network topologies with different geographical footprints. We
show that, with optical power properly optimized, BDM may enable an
increase in network traffic, slightly less than an SDM upgrade but
still comparable, without requiring additional fiber cables.
“It really proves to us that we are still valuable”: Qualitative research to inform a safer conception intervention for men living with HIV in South Africa
Authors: Matthews Lynn T. , Greener Letitia , Khidir Hazar , Psaros Christina , Harrison Abigail , Mosery F. Nzwakie , Mathenjwa Mxolisi , O’Neil Kasey , Milford Cecilia , Safren Steven A. , Bangsberg David R. , Smit Jennifer A. 
Published: March 2021

ObjectiveMany men living with HIV want to have children. Opportunities to reduce periconception HIV transmission include antiretroviral therapy as prevention, pre-exposure prophylaxis, limiting condomless sex to peak fertility, and sperm processing. Whether men have knowledge of or want to adopt these strategies remains unknown.MethodsWe conducted focus group discussions (FGDs) with men accessing HIV care in South Africa in 2014 to inform a safer conception intervention for men. Eligible men were 25–45 years old, living with HIV, not yet accessing treatment, and wanting to have a child with an HIV-negative or unknown serostatus female partner (referred to as the “desired pregnancy partner”). FGDs explored motivations for having a healthy baby, feasibility of a clinic-based safer conception intervention, and acceptability of safer conception strategies. Data were analyzed using thematic analysis.ResultsTwelve participants from three FGDs had a median age of 37 (range 23–45) years, reported a median of 2 (range 1–4) sexual partners, and 1 (range 1–3) desired pregnancy partner(s). A third (N = 4) had disclosed HIV-serostatus to the pregnancy partner. Emergent themes included opportunities for and challenges to engaging men in safer conception services. Opportunities included enthusiasm for a clinic-based safer conception intervention and acceptance of some safer conception strategies. Challenges included poor understanding of safer conception strategies, unfamiliarity with risk reduction [versus “safe” (condoms) and “unsafe” (condomless) sex], mixed acceptability of safer conception strategies, and concerns about disclosing HIV-serostatus to a partner.ConclusionsMen living with HIV expressed interest in safer conception and willingness to attend clinic programs. Imprecise prevention counseling messages make it difficult for men to conceptualize risk reduction. Effective safer conception programs should embrace clear language, e.g. undetectable = untransmittable (U = U), and support multiple approaches to serostatus disclosure to pregnancy partners.
Are adversities and worries during the COVID-19 pandemic related to sleep quality? Longitudinal analyses of 46,000 UK adults
Authors: Wright Liam , Steptoe Andrew , Fancourt Daisy 
Published: March 2021

Background
There are concerns that both the experience of adversities during the COVID-19 pandemic and worries about experiencing adversities will have substantial and lasting effects on mental health. One pathway through which both experience of and worries about adversity may impact health is through effects on sleep.

Methods
We used data from 46,284 UK adults in the COVID-19 Social Study assessed weekly from 01/04/2020-12/05/2020 to study the association between adversities and sleep quality. We studied six categories of adversity including both worries and experiences of: illness with COVID-19, financial difficulty, loss of paid work, difficulties acquiring medication, difficulties accessing food, and threats to personal safety. We used random-effect within-between models to account for all time-invariant confounders.

Results
Both the total number of adversity experiences and total number of adversity worries were associated with lower quality sleep. Each additional experience was associated with a 1.16 (95% CI = 1.10, 1.22) times higher odds of poor quality sleep while each additional worry was associated with a 1.20 (95% CI = 1.17, 1.22) times higher odds of poor quality sleep. When considering specific experiences and worries, all worries and experiences were significantly related to poorer quality sleep except experiences relating to employment and finances. Having a larger social network offered some buffering effects on associations but there was limited further evidence of moderation by other social or psychiatric factors.

Conclusion
Poor sleep may be a mechanism by which COVID-19 adversities are affecting mental health. This highlights the importance of interventions that support adaptive coping strategies during the pandemic.
Impact of adenosine on mechanisms sustaining persistent atrial fibrillation: Analysis of contact electrograms and non-invasive ECGI mapping data
Authors: Dhillon Gurpreet Singh , Ahluwalia Nikhil , Honarbakhsh Shohreh , Graham Adam , Creta Antonio , Abbass Hakam , Chow Anthony , Earley Mark J. , Lambiase Pier D. , Schilling Richard J. , Hunter Ross J. 
Published: March 2021

Background
We evaluated the effect of adenosine upon mechanisms sustaining persistent AF through analysis of contact electrograms and ECGI mapping.

Methods
Persistent AF patients undergoing catheter ablation were included. ECGI maps and cycle length (CL) measurements were recorded in the left and right atrial appendages and repeated following boluses of 18 mg of intravenous adenosine. Potential drivers (PDs) were defined as focal or rotational activations completing ≥ 1.5 revolutions. Distribution of PDs was assessed using an 18 segment biatrial model.

Results
46 patients were enrolled. Mean age was 63.4 ± 9.8 years with 33 (72%) being male. There was no significant difference in the number of PDs recorded at baseline compared to adenosine (42.1 ± 15.2 vs 40.4 ± 13.0; p = 0.417), nor in the number of segments harbouring PDs, (13 (11–14) vs 12 (10–14); p = 0.169). There was a significantly higher percentage of PDs that were focal in the adenosine maps (36.2 ± 15.2 vs 32.2 ± 14.4; p < 0.001). There was a significant shortening of CL in the adenosine maps compared to baseline which was more marked in the right atrium than left atrium (176.7 ± 34.7 vs 149.9 ± 27.7 ms; p < 0.001 and 165.6 ± 31.7 vs 148.3 ± 28.4 ms; p = 0.003).

Conclusion
Adenosine led to a small but significant shortening of CL which was more marked in the right than left atrium and may relate to shortening of refractory periods rather than an increase in driver burden or distribution.
Registered on Clinicaltrials.gov: NCT03394404.
Initiation of postpartum modern contraceptive methods: Evidence from Tanzania demographic and health survey
Authors: Rwabilimbo Martin M. , Elewonibi Bilikisu R. , Yussuf Mashavu H. , Robert Masanja , Msuya Sia E. , Mahande Michael J. 
Published: March 2021

Background
Postpartum contraceptive use is vital to improve maternal and child survival. It helps to have optimal child spacing, prevent unplanned pregnancies and associated adverse birth outcomes. However, postpartum contraceptive use in Tanzania remains low. Short median interval for resumption to sex after birth among African women has been associated with adverse maternal and child health wellbeing. This study aimed to assess optimal time to contraceptive use and predictors of time to contraceptive use after birth among women of reproductive age in Tanzania.

Methods
A cross section study using the TDHS 2015–16 data was used. A total of 3775 postpartum women were analyzed. Information on pregnancy, births and contraceptive use were recorded over the previous 5 years with the focus on most recent birth from the contraceptive calendar. Data analysis was performed using Stata 14.0. Analysis accounted for complex survey design. Time to modern contraceptive use after birth was computed using Kaplan Meier estimate. Adjusted time ratios with 95% CI were estimated using Weibull accelerated failure time models.

Results
A total weighted sample of 3775 women was analyzed. The median time to contraceptive use after birth was 7(IQR: 4–13) months, while for resumption to sex afterbirth was 2(IQR: 1–5) months. Factors such as never been married (TR: 1.63; 95%CI: 1.26–2.11) and breastfeeding (TR: 5.50; 95%CI: 4.12–7.35) were associated with longer time to postpartum contraceptive use. Belonging to richest wealth quintile (TR: 0.73; 95%CI: 0.54–0.99) and adopting long acting methods (TR: 0.70; 95%CI: 0.60–0.82) increased women’s likelihood of having shorter time to postpartum contraceptive use.

Conclusion
There was a time lag of five months from resumption of sex and initiation of postpartum contraception use. The interceptive measures to facilitate timely availing methods of women’s choice and promotion of utilization of maternal health care services may reduce delays in postpartum contraceptive use.