An improved Newton-Raphson based linear power flow method for DC grids with dispatchable DGs and ZIP loads

Purpose This study aims to provide a solution of the power flow calculation for the low-voltage ditrect current power grid. The direct current (DC) power grid is becoming a reliable and economic alternative to millions of residential loads. The power flow (PF) in the DC network has some similarities with the alternative current case, but there are important differences that deserve to be further concerned. Moreover, the dispatchable distributed generators (DGs) in DC network can realize the flexible voltage control based on droop-control or virtual impedance-based methods. Thus, DC PF problems are still required to further study, such as hosting all load types and different DGs. Design/methodology/approach The DC power analysis was explored in this paper, and an improved Newton–Raphson based linear PF method has been proposed. Considering that constant impedance (CR), constant current (CI) and constant power (CP) (ZIP) loads can get close to the practical load level, ZIP load has been merged into the linear PF method. Moreover, DGs are much common and can be easily connected to the DC grid, so V nodes and the dispatchable DG units with droop control have been further taken into account in the proposed method. Findings The performance and advantages of the proposed method are investigated based on the results of the various test systems. The two existing linear models were used to compare with the proposed linear method. The numerical results demonstrate enough accuracy, strong robustness and high computational efficiency of the proposed linear method even in the heavily-loaded conditions and with 10 times the line resistances. Originality/value The conductance corresponding to each constant resistance load and the equivalent conductance for the dispatchable unit can be directly merged into the self-conductance (diagonal component) of the conductance matrix. The constant current loads and the injection powers from dispatchable DG units can be treated as the current sources in the proposed method. All of those make the PF model much clear and simple. It is capable of offering enough accuracy level, and it is suitable for applications in DC networks that require a large number of repeated PF calculations to optimize the energy flows under different scenarios.

The Association between COVID-19-Related Wellbeing with Materialism and Perceived Threat

The ongoing coronavirus disease (COVID-19) pandemic has had a profound impact on people’s wellbeing. Here, we proposed that an individual characteristic might be associated with wellbeing; that is, materialism. Specifically, we conducted three studies (total N = 3219) to examine whether people with high levels of materialism would experience poorer wellbeing (i.e., anxiety and depression, in the current case). The results showed that materialism was positively associated with depression (Studies 1A, 1B and 2) and anxiety (Study 2). Moreover, such a relationship was mediated by people’s perceived threat of COVID-19 (Study 2). These findings were observed in both Chinese and American people. The findings are discussed in terms of their theoretical and practical contributions.

Botulinum Toxin Injection for Painful Adductor Pollicis Contracture after Thumb Carpometacarpal Resection Arthroplasty

Pollux adductus deformity is an accompanying symptom of thumb carpometacarpal osteoarthritis. We describe a case of a patient who presented with increased muscle tone of the adductor pollicis muscle and chronic pain in the thenar musculature, i.e., recurrence of an adduction deformity. The patient reported a symptom-free period of 5.5 years after having received resection-suspension-arthroplasty for stage IV thumb carpometacarpal osteoarthritis until spasmodic pain appeared. Due to the functional impairment of this condition, we administered therapy including 100 units of Botox® (onabotulinumtoxinA, Allergan, Dublin, Ireland) injected with a fanning technique into the adductor pollicis muscle. Thus, we observed a substantial improvement in the patient-reported outcome measures as well as pain levels compared with initial values. The current case shows the pivotal role of the adductor pollicis muscle when patients report pain at the base of the thumb, which can cause considerable impairments despite the complication-free surgical treatment of thumb CMC OA.

A Novel Approach to Reservoir Simulation of Hydraulic Fractures: Performance Improvement Using Pseudo Well Connections

Reservoir simulation is used in most modern reservoir studies to predict future production of oil and gas, and to plan the development of the reservoir. The number of hydraulically fractured wells has risen drastically in recent years due to the increase in production in unconventional reservoirs. Gone are the days of using simple analytic techniques to forecast the production of a hydraulic fracture in a vertical well, and the need to be able to model multiple hydraulic fractures in many stages over long horizontals is now a common practice. The type of simulation approach chosen depends on many factors and is study specific. Pseudo well connection approach was preferred in the current case. Due to the nature of the reservoir simulation problem, a decision needs to be made to determine which hydraulic fracture modeling method might be most suitable for any given study. To do this, a selection of methods is chosen based on what is available at hand, and what is commonly used in various reservoir simulation software packages. The pseudo well connection method, which models hydraulic fractures as uniform conductivity rectangular fractures was utilized for a field of interest referred to as Field A in this paper. Such an assumption of the nature of the hydraulic fracture is common in most modern tools. Field A is a low permeability (0.01md-0.1md), tight (8% to 12% porosity) gas-condensate (API ~51deg and CGR~65 stb/mmscf) reservoir at ~3000m depth. Being structurally complex, it has a large number of erosional features and pinch-outs. The pseudo well connection approach was found to be efficient both terms of replicating data of Field A for a 10 year period while drastically reducing simulation runtime for the subsequent 10 year-period too. It helped the subsurface team to test multiple scenarios in a limited time-frame leading to improved project management.

Implantation of a VDD implantable cardioverter-defibrillator lead via a persistent left superior vena cava

A persistent left superior vena cava (LSVC) represents a challenging congenital abnormality for transvenous cardiac device implantation. In the current case a secondary prophylactic VDD implantable cardioverter-defibrillator (ICD) implantation was planned in a 75-year-old woman presenting with ischemic cardiomyopathy and elevated stroke risk. Since no venous communication to the right side was identified intraoperatively, the lead was placed via the persistent LSVC. The far-field signal on the floating atrial dipole could be successfully blanked out, and appropriate device function with high and stable atrial sensing was demonstrated at follow-up.

Proof of Concept in Assignment of Within-Subject Variability During Virtual Bioequivalence Studies: Propagation of Intra-Subject Variation in Gastrointestinal Physiology Using Physiologically Based Pharmacokinetic Modeling

While the concept of ‘Virtual Bioequivalence’ (VBE) using a combination of modelling, in vitro tests and integration of pre-existing data on systems and drugs is growing from its infancy, building confidence on VBE outcomes requires demonstration of its ability not only in predicting formulation-dependent systemic exposure but also the expected degree of population variability. The concept of variation influencing the outcome of BE, despite being hidden with the cross-over nature of common BE studies, becomes evident when dealing with the acceptance criteria that consider the 90% confidence interval (CI) around the relative bioavailability. Hence, clinical studies comparing a reference product against itself may fail due to within-subject variations associated with the two occasions that the individual receives the same formulation. In this proof-of-concept study, we offer strategies to capture the most realistic predictions of CI around the pharmacokinetic parameters by propagating physiological variations through physiologically based pharmacokinetic modelling. The exercise indicates feasibility of the approach based on comparisons made between the simulated and observed WSV of pharmacokinetic parameters tested for a clinical bioequivalence case study. However, it also indicates that capturing WSV of a large array of physiological parameters using backward translation modelling from repeated BE studies of reference products would require a diverse set of drugs and formulations. The current case study of delayed-release formulation of posaconazole was able to declare certain combinations of WSV of physiological parameters as ‘not plausible’. The eliminated sets of WSV values would be applicable to PBPK models of other drugs and formulations.

Pseudopterygium in a Rabbit - Treatment with Tracolinus

Background: Pseudopterygium, also known as aberrant conjunctival growth, is poorly described in the literature, although it is known that this abnormality is uncommon and affects dwarf rabbits and their crossbreeds. The etiology of this disease is unknown, but there are hypotheses that the conjunctival growth cause may have its origins in immunological factors, inflammation, traumatic conditions, or cartilage dysplasias. Thus, this study reports the treatment efficacy applied in a rabbit, through the continuous use of tracolimus eye drops, after surgical procedure of conjunctival fold resection, as a way of controlling the pseudopterygium in rabbits.Case: This case report discusses the positive results from the surgical and therapeutic conduct of a clinical case attended by the Ophthalmology and Microsurgical Veterinary Service at the Hospital Veterinário Universitário (HVU) of the UFSM. The patient was a male rabbit, sterilized cunicle, approximately 2-year-old, crossed with a dwarf rabbit. The owner's main complaint was the change in the aspect of the left eye, with progressive worsening in the previous four weeks. In the ophthalmological examination, the animal did not present impaired vision or discomfort, however, a vascularized pink membrane was noted, which consisted of a fold of the bulbar conjunctiva, that grew centripetally and covered 90% of the cornea in 360 degrees. The diagnosis was confirmed through visual inspection and the patient's history. The eye alteration had a characteristic aspect, described as proliferation of the bulbar conjunctiva over the cornea, in a centripetal manner and without signs of inflammation. In addition, other ophthalmological alterations were ruled out during the patient's physical and specific examination. The patient was referred for anesthetic evaluation and, in addition, pre-surgical blood tests were performed, which were normal, according to the expected ranges for the species. Subsequently, the animal was submitted to surgical treatment, which consisted of dividing the exuberant conjunctiva, followed by three radial incisions in equal portions. Next, the conjunctival fold was completely incised to the edge of the limbus, without the need of sutures. Anterior lamellar keratectomy was performed on the portion where the membrane was attached to the cornea. For home care, tobramycin-based eye drops (QID, for 7 days) and 0.02% aqueous tacrolimus eye drops (BID - continuous use) were prescribed. The animal was reevaluated 7, 14, 30, 60, 120 and 180 days after surgical correction, and no recurrence of pseudopterygium was observed during the follow-up period. The prognosis of patients with pseudopterygium is reserved, as it is known that the disease may recur after surgical treatment. Therefore, the continuous use of the chosen immunomodulating eye drops was recommended as well as periodic follow-up of the patient.Discussion: In the current study, it was not possible to increase knowledge regarding about the pseudopterygium etiology. Although the condition is not serious, it can cause partial impairment of vision and chronic discomfort. However, the vision field described in the rabbit in this current case remained unchanged, in accordance with other cases described in the literature. Furthermore, no signs of patient discomfort were detected. Some surgical techniques described in the literature for correction of pseudopterygium, shows membrane’s growth recurrence. The use of immunomodulatory drugs is suggested for relapses controlling. In this study, the tracolimus eye drops efficacy was tested, and presented good results in the patient's evaluations for a long period after surgery. The use of immunomodulators is an option for adjuvant topical treatment for controlling pseudopterygium growth, which, associated with corrective surgical treatment, has shown positive results.Keywords: conjunctiva, aberrant, immunomodulator, treatment, bunny.Título: Pseudopterígio em coelho - tratamento com tracolimusDescritores: conjuntiva, aberrante, imunomodulador, tratamento, coelho.

Acute Lymphoblastic Leukemia Presenting as Pituitary Apoplexy: A Case Report and Review of the Literature

Thrombocytopenia as a precipitating factor for pituitary apoplexy (PA) is very rare event. There are only five reported cases of PA secondary to thrombocytopenia caused by underlying haematological malignancy. Herein, we report a case of 60-year-old male presenting with acute-onset headache, bilateral vision loss, and ptosis. Computed tomography and magnetic resonance imaging revealed findings indicative of pituitary adenoma with apoplexy. He was noted to have thrombocytopenia, and bone marrow evaluation revealed precursor B-lineage CALLA-positive acute lymphoblastic leukemia. Accordingly, he was started on dexamethasone and vincristine but succumbed to Acinetobacter baumanii-related hospital-acquired pneumonia two weeks after initiation of chemotherapy. We performed a literature search and found five cases of pituitary apoplexy secondary to haematological malignancy-related thrombocytopenia. The usual age of presentation was in the 6th to 7th decade, and there was slight male preponderance. The underlying pituitary adenoma was either nonfunctioning or a prolactinoma, and in majority, the apoplexy event occurred after the diagnosis of haematological malignancy. The platelet counts at the time of PA were less than 30 × 109/L in all, and the malignancy subtypes were acute or chronic myeloid leukemia and chronic lymphoid leukemia. The current case highlights the importance of careful evaluation for the cause of thrombocytopenia in a case of PA.

Tiger-Striped PASH: Recognition of a Unique Morphology Allows for a Zippered-Up Diagnosis of Pseudoangiomatous Stromal Hyperplasia of Breast

Pseudoangiomatous stromal hyperplasia (PASH) of the breast is histologically characterized by anastomosing and slit-like spaces invested by collagenous stroma and lined by flattened, spindle cells. These clear spaces that may mimic microscopic vascular channels do not contain red blood cells. Immunohistochemistry (IHC) studies may also help to confirm a diagnosis of PASH, with the spindled cells marking positively with CD34 and PR while demonstrating no reactivity with more specific endothelial antigens such as CD31 and ERG. In the current case, a 39-year-old female was diagnosed with cellular PASH of the right breast with unique histological patterns showing “tiger-striped” and “zippered” histologies. To our knowledge, this is the first report of these unique variant PASH morphologies.

Representation Learning and Similarity of Legal Judgements using Citation Networks

India and many other countries like UK, Australia, Canada follow the ‘common law system’ which gives substantial importance to prior related cases in determining the outcome of the current case. Better similarity methods can help in finding earlier similar cases, which can help lawyers searching for precedents. Prior approaches in computing similarity of legal judgements use a basic representation which is either abag-of-words or dense embedding which is learned by only using the words present in the document. They, however, either neglect or do not emphasize the vital ‘legal’ information in the judgements, e.g. citations to prior cases, act and article numbers or names etc. In this paper, we propose a novel approach to learn the embeddings of legal documents using the citationnetwork of documents. Experimental results demonstrate that the learned embedding is at par with the state-of-the-art methods for document similarity on a standard legal dataset.