Application of artificial dynamics to represent non-isolated single-input multiple-output DC-DC converters with averaged models

This paper presents for the first time the application of a method based on the transformation of the differential algebraic equations of non-isolated Single-Input Multiple Output (SIMO) DC-DC converters into a set of ordinary differential equations, by using artificial dynamics whose asymptotic convergence to the solution is guaranteed by the satisfaction of the relevant Lyapunov conditions. The mathematical formulation is simpler than in other formulations applied in the literature to study non-isolated SIMO DC-DC converters, and encompasses the use of sensitivity functions. The results show that the proposed solution represents in a fully accurate way the dynamics of the averaged models of Zeta Buck-Boost and Cúk Boost Combination converters

Analysis of caesarean section and neonatal outcome using the Robson classification in a rural district hospital in Tanzania: An observational retrospective study

OBJECTIVE: Caesarean section (CS) rates have increased worldwide in recent decades. In 2015, the WHO proposed the use of the 10-group Robson classification as a global standard for assessing, monitoring and comparing CS rates both within healthcare facilities over time and between them. The aim of this study was to assess the pattern of CS rates according to the Robson classification and describe maternal and perinatal outcomes by group at the Tosamaganga Hospital in rural Tanzania. DESIGN: Observational retrospective study. SETTING: St. John of the Cross Tosamaganga Hospital, a referral centre in rural Tanzania. PARTICIPANTS: 3012 women who gave birth in Tosamaganga Hospital from 1 January to 30 June 2014 and from 1 March to 30 November 2015. RESULTS: The overall CS rate was 35.2%, and about 90% of women admitted for labour were in Robson groups 1 through 5. More than 40% of the CS carried out in the hospital were performed on nulliparous women at term with a single fetus in cephalic presentation (groups 1 and 3), and the most frequent indication for the procedure was previous uterine scar (39.2%). The majority of severe neonatal outcomes were observed in groups 1 (27.7%), 10 (24.5%) and 3 (19.1%). CONCLUSION: We recorded a high CS rate in Tosamaganga Hospital, particularly in low-risk patients groups (Robson groups 1 and 3). Our analysis of Robson classification and neonatal outcomes suggests the need to improve labour management at the hospital and to provide timely referrals in order to prevent women from arriving there in critical conditions

Optimal discretization of grounding systems applying Maxwell's subareas method

This paper presents a method for evaluating the optimal number n of equivalent sources needed for simulating grounding systems by the Maxwell's subareas method. It is well known that the number of elements in which electrodes are subdivided plays a role on the accuracy and reliability of results (as well as on computational time). Previous studies, accomplished through iterative calculations (performed with different segmentations), led mostly to some recommended practices for the identification of lower and upper bounds for n. The procedure proposed in this paper allows for predicting the optimal n in a single process. The method starts from the identification of a set of appropriate scalar functions, which heuristically express a relation between the number of subareas and the accuracy of the results (earth resistance and earth surface voltages) computed applying the Maxwell's subareas method. Then, a multi-objective optimization process evaluates the number n* that maximizes that accuracy

Influence of dialysate temperature on creatinine peritoneal clearance in peritoneal dialysis patients: a randomized trial

Background: Patients on continuous ambulatory peritoneal dialysis (PD) are encouraged to warm dialysate to 37 \ub0C before peritoneal infusion; main international PD guidelines do not provide specific recommendation, and patients generally warm dialysate batches partially or do not warm them at all. Warming of dialysate is a time-consuming procedure, not free from potential risks (i.e. degradation of glucose), and should be justified by a clear clinical benefit. Methods: We designed a single blind randomized controlled trial where 18 stable PD patients were randomized to receive a peritoneal equilibration test either with dialysate at a controlled temperature of 37 \ub0C (intervention group) or with dialysate warmed with conventional methods (control group). Primary end-point was a higher peritoneal creatinine clearance in patients in the intervention group. Results: Patients in the intervention group did not show a significantly higher peritoneal creatinine clearance when compared to the control group (6.38 \ub1 0.52 ml/min vs 5.65 \ub1 0.37 ml/min, p = 0.2682). Similar results were obtained for urea peritoneal clearance, mass transfer area coefficient of creatinine and urea. There were no significant differences in total abdominal discomfort questionnaire score, blood pressure and body temperature between the two groups. Conclusions: Using peritoneal dialysate at different temperatures without causing significant side effects to patients appears feasible. We report a lack of benefit of warming peritoneal dialysate to 37 \ub0C on peritoneal clearances; future PD guidelines should not reinforce this recommendation. Trial registration: NCT04302649, ClinicalTrials.gov; date of registration 10/3/2020 (retrospectively registered)

Proximity-induced ferromagnetism and chemical reactivity in few-layer VSe2 heterostructures

Among transition-metal dichalcogenides, mono and few-layers thick VSe2 has gained much recent attention following claims of intrinsic room-temperature ferromagnetism in this system, which have nonetheless proved controversial. Here, we address the magnetic and chemical properties of Fe/VSe2 heterostructure by combining element sensitive x-ray absorption spectroscopy and photoemission spectroscopy. Our x-ray magnetic circular dichroism results confirm recent findings that both native mono/few-layer and bulk VSe2 do not show intrinsic ferromagnetic ordering. Nonetheless, we find that ferromagnetism can be induced, even at room temperature, after coupling with a Fe thin film layer, with antiparallel alignment of the moment on the V with respect to Fe. We further consider the chemical reactivity at the Fe/VSe2 interface and its relation with interfacial magnetic coupling

Decay Constants of Heavy-Light Mesons

The decay constants of the heavy-light pseudoscalar mesons are studied in a high statistics run using the Wilson action at $\beta=6.0$ and $\beta=6.2$, and the clover action at $\beta=6.0$. The systematics of $O(a)$ discretisation errors are discussed. Our best estimates of the decay constants are: $f_D$ = 218(9) MeV, $f_D/f_{Ds}$ = 1.11(1) and we obtain preliminary values for $f_B$.Comment: at the Dallas Lattice Conference, October 1993. 3 pages in a single postscript file, uuencoded form. Rome Preprint 93/98

Fatal herpesvirus-6 encephalitis in a recipient of a T-cell-depleted peripheral blood stem cell transplant from a 3-loci mismatched related donor

Human herpesvirus-6 (HHV-6), like all the other herpes viruses, remains latent in host cells after primary infection but can be reactivated In immuno-compromised patients causing fever, skin rash, bone marrow (BM) suppression, pneumonitis, Sinusitis and meningoencephalitis. We describe the case of a man with chronic myelogenous leukemia who developed encephalitis associated with acute graft-versus-host disease two months after a T-cell-depleted mismatched peripheral blood stem cell transplant. Magnetic resonance images of the brain revealed multiple bilateral foci of signal abnormality. HHV-6 was the only pathogen detected in cerebrospinal fluid by PCR. treatment with both ganciclovir and foscarnet was unsuccessful and the patient gradually deteriorated and died. Other cases of HHV-6 encephalitis after bone marrow transplantation are reviewed

Ruling out coronavirus disease 2019 in patients with pneumonia: The role of blood cell count and lung ultrasound

Coronavirus disease 2019 (COVID-19) is characterized by a distinctive blood leucocyte pattern and B-lines on lung ultrasound (LUS) as marker of alveolar-interstitial syndrome. We aimed to evaluate the accuracy of blood leucocyte count alone or in combination with LUS for COVID-19 diagnosis. We retrospectively enrolled consecutive patients diagnosed with community acquired pneumonia (CAP) at hospital admission to derive and validate cutoff values for blood cell count that could be predictive of COVID-19 before confirmation by the nucleic acid amplification test (NAAT). Cutoff values, generated and confirmed in inception (41/115, positive/negative patients) and validation (100/180, positive/negative patients) cohorts, were ≤17 and ≤10 cells/mm3 for basophils and eosinophils, respectively. Basophils and/or eosinophils below cutoff were associated with sensitivity of 98% (95%CI, 94–100) and negative likelihood ratio of 0.04 (95%CI, 0.01–0.11). In a subgroup of 265 subjects, the sensitivity of B-line on LUS was 15% lower (p < 0.001) than that of basophils and/or eosinophils below cutoff. The combination of B-lines with basophils and eosinophils below cutoff was associated with a moderate increase of the positive likelihood ratio: 5.0 (95%CI, 3.2–7.7). In conclusion, basophil and eosinophil counts above the generated cutoff virtually rule out COVID-19 in patients with CAP. Our findings can help optimize patient triage pending the NAAT results