Foundations of self-consistent particle-rotor models and of self-consistent cranking models

The Kerman-Klein formulation of the equations of motion for a nuclear shell model and its associated variational principle are reviewed briefly. It is then applied to the derivation of the self-consistent particle-rotor model and of the self-consistent cranking model, for both axially symmetric and triaxial nuclei. Two derivations of the particle-rotor model are given. One of these is of a form that lends itself to an expansion of the result in powers of the ratio of single-particle angular momentum to collective angular momentum, that is essentual to reach the cranking limit. The derivation also requires a distinct, angular-momentum violating, step. The structure of the result implies the possibility of tilted-axis cranking for the axial case and full three-dimensional cranking for the triaxial one. The final equations remain number conserving. In an appendix, the Kerman-Klein method is developed in more detail, and the outlines of several algorithms for obtaining solutions of the associated non-linear formalism are suggested.Comment: 29 page

Quantitative imaging of concentrated suspensions under flow

We review recent advances in imaging the flow of concentrated suspensions, focussing on the use of confocal microscopy to obtain time-resolved information on the single-particle level in these systems. After motivating the need for quantitative (confocal) imaging in suspension rheology, we briefly describe the particles, sample environments, microscopy tools and analysis algorithms needed to perform this kind of experiments. The second part of the review focusses on microscopic aspects of the flow of concentrated model hard-sphere-like suspensions, and the relation to non-linear rheological phenomena such as yielding, shear localization, wall slip and shear-induced ordering. Both Brownian and non-Brownian systems will be described. We show how quantitative imaging can improve our understanding of the connection between microscopic dynamics and bulk flow.Comment: Review on imaging hard-sphere suspensions, incl summary of methodology. Submitted for special volume 'High Solid Dispersions' ed. M. Cloitre, Vol. xx of 'Advances and Polymer Science' (Springer, Berlin, 2009); 22 pages, 16 fig

Surgical management of persistent post-traumatic trans-tentorial brain hernia [Prise en charge chirurgicale de la hernie cérébrale trans-tentorielle post-traumatique persistante]

Introduction: Temporal engagement may persist after etiologic surgical treatment of acute subdural hematoma (ASH) without clinical improvement despite normalized intracranial pressure (ICP). The aim of this study was to assess the feasibility of secondary direct temporal lobe disengagement (DTLD) after surgery for supratentorial ASH and to evaluate clinical outcome. Materials and methods: This was a retrospective analysis of 4 patients undergoing secondary DTLD. Patient data were recorded at admission, pre- and postoperatively and at 6 months’ follow-up (FU): age, gender, Rotterdam score, Glasgow Coma Scale (GCS), neurological deficits, oculomotor nerve palsy (ONP), ICP, midline shift, complications and Extended Glasgow Outcome Scale (GOS-E). Results: At postoperative evaluation 48 h after DTLD, we observed a significant improvement in GCS score (initial 6 ± 3, preoperative 7 ± 3, postoperative 14 ± 1; P = 0.02), midline shift (initial 16 ± 3 mm, preoperative 13 ± 5 mm, postoperative 9 ± 2 mm; P = 0.049) and ONP (P = 0.01). In all cases, early postoperative imaging documented visualization of a patent ipsilateral peri-mesencephalic cistern. At 6-month FU, GOS-E showed 75% good recovery and 25% disability. Complete ONP recovery was observed in 75% of patients (P = 0.01). Neurological deficits were present at FU in 25% of patients. No surgery-related complications or mortality were recorded. Conclusions: In traumatic brain injury, secondary DTLD may allow simple, effective and safe management of trans-tentorial uncal herniation, avoiding more challenging procedures. Clinical results are promising, as this technique seems to favorably influence neurological outcome in this selected subgroup of patients with persistent clinical and radiological signs of temporal engagement after etiological treatment with normal ICP values.Introduction. – L’engagement temporal peut persister après le traitement chirurgical étiologique de l’hématome sous-dural aigu (HSDA) sans amélioration clinique malgré la normalisation de la pression intracrânienne (PIC). Le but de cette étude est d’évaluer la faisabilité du désengagement secondaire direct du lobe temporal (DSDLT) après une chirurgie pour une HSDA supratentorielle et d’évaluer les résultats cliniques. Matériel et méthodes. – Il s’agit d’une analyse rétrospective de 4 patients opérés pour un DSDLT. Les variables des patients (âge, sexe, score de Rotterdam, Glasgow Coma Scale [GCS], présence de déficits neurologiques, paralysie du nerf oculomoteur [PNO], surveillance PIC, shift de la ligne médiane, complications et Extended Glasgow Outcome Scale [GOS-E]) ont été enregistrées à l’admission, avant et après l’opération et au suivi à 6 mois. Résultats. – À l’évaluation précoce des résultats (48 h après DSDLT), nous avons observé une amélioration significative du score GCS (initial 6 ± 3, préopératoire 7 ± 3, postopératoire 14 ± 1, p = 0,02), du shift de la ligne médiane (initial 16 ± 3 mm, préopératoire 13 ± 5 mm, postopératoire 9 ± 2 mm, p = 0,049) et de la PNO (p = 0,01). Dans tous les patients, l’imagerie postopératoire précoce a documenté la visualisation d’une citerne péri-mésencéphalique homolatérale perméable. À l’évaluation à six mois, les distributions du score GOS-E étaient les suivantes : bon rétablissement 75 %, handicap sévère 25 %. Une récupération de la PNO complète a été observée dans 75 % des patients (p = 0,01). Des déficits neurologiques étaient présents à 6 mois dans 25 % des patients. Aucune complication et mortalité liées à la chirurgie n’ont été enregistrées. Conclusions. – Dans le cadre du traumatisme crânien, le DSDLT peut permettre une prise en charge simple, efficace de la hernie uncaltrans-tentorielle évitant des procédures plus difficiles. Les résultats cliniques sont prometteurs, car cette technique semble influencer favorablement les résultats neurologiques de ce sous-groupe sélectionné de patients présentant des signes cliniques et radiologiques persistants d’engagement temporel après un traitement étiologique avec des valeurs de PIC normales. © 2021 Elsevier Masson SAS. Tous droits reserves

Does the sole description of a tax authority affect tax evasion? The impact of described coercive and legitimate power.

Following the classic economic model of tax evasion, taxpayers base their tax decisions on economic determinants, like fine rate and audit probability. Empirical findings on the relationship between economic key determinants and tax evasion are inconsistent and suggest that taxpayers may rather rely on their beliefs about tax authority’s power. Descriptions of the tax authority’s power may affect taxpayers’ beliefs and as such tax evasion. Experiment 1 investigates the impact of fines and beliefs regarding tax authority’s power on tax evasion. Experiments 2-4 are conducted to examine the effect of varying descriptions about a tax authority’s power on participants’ beliefs and respective tax evasion. It is investigated whether tax evasion is influenced by the description of an authority wielding coercive power (Experiment 2), legitimate power (Experiment 3), and coercive and legitimate power combined (Experiment 4). Further, it is examined whether a contrast of the description of power (low to high power; high to low power) impacts tax evasion (Experiments 2-4). Results show that the amount of fine does not impact tax payments, whereas participants’ beliefs regarding tax authority’s power significantly shape compliance decisions. Descriptions of high coercive power as well as high legitimate power affect beliefs about tax authority’s power and positively impact tax honesty. This effect still holds if both qualities of power are applied simultaneously. The contrast of descriptions has little impact on tax evasion. The current study indicates that descriptions of the tax authority, e.g., in information brochures and media reports, have more influence on beliefs and tax payments than information on fine rates. Methodically, these considerations become particularly important when descriptions or vignettes are used besides objective information

Managing Incomplete and Complete Thoracolumbar Burst Fractures (AO Spine A3 and A4). Results from a Prospective Single-Center Study Comparing Posterior Percutaneous Instrumentation plus Mini-Open Anterolateral Fusion versus Single-Stage Posterior Instrumented Fusion

Objective: The treatment strategy for thoracolumbar burst fractures is still debated. The aim of this study is to evaluate clinical and radiologic outcomes of a 2-stage strategy with immediate posterior percutaneous instrumentation and delayed anterolateral fusion (group A) versus a single-stage open posterior instrumented fusion (group B). Methods: Demographics and clinical and surgical data of patients operated for AO Spine A3 and A4 fractures were prospectively collected. Vertebral height and deformity were evaluated before and after surgery. Visual analog scale score for back pain, Oswestry Disability Index, and 12-Item Short Form Health Survey results for quality-of-life assessment were collected during follow-up. Results: Among the 110 patients enrolled, 66 were allocated to group A and 44 to group B; the most common fractured level was T12 (34%). Postoperative complications were higher in group B, especially the wound infection rate (18% vs. 3%), and pseudomeningocele (14% vs. 0%). The 2-stage approach allowed an average long-term gain of 15.8° at the local kyphosis of fractured vertebra and 5.8° at the regional level (Cobb angle), versus 15.4° and 5.5° in group B. At 2 years follow-up, both groups showed significant functional improvements; however, the visual analog scale and Oswestry Disability Index metrics seemed more favorable for group A patients (P < 0.0001 vs. P < 0.003). A complete fusion rate was obtained in 100% of group A vs. 65% of group B. Conclusions: Our study indicates that percutaneous instrumentation and anterior fusion or an expandable cage lead to excellent long-term clinical and radiologic outcomes with a lower complication rate and higher fusion rate than those of open posterior approaches

Approaching Intradural Lesions of the Anterior Foramen Magnum and Craniocervical Junction: Anatomical Comparison of the Open Posterolateral and Anterior Extended Endonasal Endoscopic Approaches

Background: Lesions of the foramen magnum (FM) and craniocervical junction area are traditionally managed surgically through anterior, anterolateral, and posterolateral skull-base approaches. This anatomical study aimed to compare the usefulness of a modified extended endoscopic approach, the so-called far-medial endonasal approach (FMEA), versus the traditional posterolateral far-lateral approach (FLA). Methods: Ten fixed silicon-injected heads specimens were used in the Skull Base ENT-Neurosurgery Laboratory of the University Hospital of Strasbourg, France. A total of 20 FLAs and 10 FMEAs were realized. A high-resolution computed tomography scan was performed for quantitative analysis of the different approaches. The analysis aimed to estimate the extent of surgical exposure and freedom of movement (maneuverability) through the operating channel using a polygonal surface model to obtain a morphometric estimation of the area of interest (surface and volume) on postdissection computed tomography scans using Slicer 3D software. Results: FMEA allows for a more direct route to the anterior FM, with wider brainstem exposure compared with the FLA and an excellent visualization of all anterior midline structures. The limitations of the FMEA include the deep and narrow surgical corridor and difficulty in reaching lesions located laterally over the jugular foramen and hypoglossal canal. Conclusions: The FMEA and FLA are both effective surgical routes to reach FM and craniocervical junction lesions. Modern skull base surgeons should have a good command of both because they appear complementary. This anatomical study provides the tools for comprehensive preoperative evaluations and selection of the most appropriate surgical approach

Dubravka Peić Čaldarović, Nikša Stančić, Povijest hrvatskoga grba: Hrvatski grb u mijenama hrvatske povijesti od 14. do početka 21. stoljeća, Zagreb: Školska knjiga, 2011., 316 str.

A series of para-oligophenylene mono- and dicarboxylic acids (R-(C6H4)nCOOH, n=1-3, R=H,COOH) was studied. Adsorbed on Au(111)/mica modified by an underpotential deposited bilayer of Ag, the self-assembled monolayers (SAMs) were analysed by near edge X-ray absorption fine structure spectroscopy, X-ray photoelectron spectroscopy and scanning tunneling microscopy. In all cases SAMs are formed with molecules adopting an upright orientation and anchored to the substrate by a carboxylate. Except benzoic acid, all SAMs could be imaged at molecular resolution, which revealed highly crystalline layers with a dense molecular packing. The structures of the SAMs are described by a rectangular (5×√3) unit cell for the prevailing phase of the monocarboxylic acids and an oblique (√93×√133) unit cell for the dicarboxylic acids, thus, evidencing a pronounced influence of the second COOH moiety on the SAM structure. Density functional theory calculations suggest that hydrogen bonding between the SAM terminating COOH moieties accounts for the difference. Contrasting other classes of SAMs, the systems studied here are determined by intermolecular interactions whereas molecule-substrate interactions play a secondary role. Thus, eliminating problems arising from the mismatch between the molecular and substrate lattices, coordinatively bonded carboxylic acids on silver should provide considerable flexibility in the design of SAM structures

Pituitary Abscess: A Challenging Preoperative Diagnosis—A Multicenter Study

Background and Objectives: Pituitary abscess (PA) is a rare occurrence, representing less than 1% of pituitary lesions, and is defined by the presence of an infected purulent collection within the sella turcica. Pas can be classified as either primary, when the underlying pituitary is normal prior to infection, or secondary, when there is associated a pre-existing sellar pathology (i.e., pituitary adenoma, Rathke’s cleft cysts, or craniopharyngioma), with or without a recent history of surgery. Preoperative diagnosis, owing to both non-specific symptoms and imaging features, remains challenging. Treatment options include endonasal trans-sphenoidal pus evacuation, as well as culture and tailored antibiotic therapy. Methods: A retrospective multicenter study, conducted on a prospectively built database over a 20-year period, identified a large series of 84 patients harboring primary sellar abscess. The study aimed to identify crucial clinical and imaging features in order to accelerate appropriate management. Results: The most common clinical presentation was a symptom triad consisting of various degrees of asthenia (75%), visual impairment (71%), and headache (50%). Diagnosis was achieved in 95% of cases peri- or postoperatively. Functional recovery was good for visual disturbances and headache. Pituitary function recovery remained very poor (23%), whereas the preoperative diagnosis represented a protective factor. Conclusions: In light of the high prevalence of pituitary dysfunction following the management of PAs, early diagnosis and treatment might represent a crucial issue. Currently, there are no standard investigations to establish a conclusive preoperative diagnosis; however, new, emerging imaging methods, in particular nuclear imaging modalities, represent a very promising tool, whose potential warrants further investigations

What is the place of surgery in the management of brain metastases in 2020?

Brain metastases are the most common intracranial tumors and are associated with a dismal prognosis. The management of patients with brain metastases has become more important because of the increased incidence of these tumours, the better treatment of the systemic disease and the improvement of surgical techniques. The treatment requires multidisciplinary approaches and become complex because of new emerging systemic therapy and advancements in neurosurgery and radiation oncology. The surgical treatment has an indispensable role to obtain a tissue diagnosis, in relieving intracranial effect mass and improving neurological status by improving induced encephalopathy. An understanding of the role and indications of the surgery in patients with metastatic brain lesions is essential for the effective management of this growing population

Primary endoscopic endonasal management of giant pituitary adenomas: Outcome and pitfalls from a large prospective multicenter experience

Purpose: To evaluate factors influencing clinical and radiological outcome of extended endoscopic endonasal transtuberculum/transplanum approach (EEA-TTP) for giant pituitary adenomas (GPAs). Methods: We recruited prospectively all consecutive GPAs patients undergoing EEA-TTP between 2015 and 2019 in 5 neurosurgical centers. Preoperative clinical and radiologic features, visual and hormonal outcomes, extent of resection (EoR), complications and recurrence rates were recorded and analyzed. Results: Of 1169 patients treated for pituitary adenoma, 96 (8.2%) had GPAs. Seventy-eight (81.2%) patients had visual impairment, 12 (12.5%) had headaches, 3 (3.1%) had drowsiness due to hydrocephalus, and 53 (55.2%) had anterior pituitary insufficiency. EoR was gross or near-total in 46 (47.9%) and subtotal in 50 (52.1%) patients. Incomplete resection was associated with lateral suprasellar, intraventricular and/or cavernous sinus extension and with firm/fibrous consistence. At the last follow-up, all but one patient (77, 98.7%) with visual deficits improved. Headache improved in 8 (88.9%) and anterior pituitary function recovered in 27 (50.9%) patients. Recurrence rate was 16.7%, with 32 months mean recurrence-free survival. Conclusions: EEA-TTP is a valid option for GPAs and seems to provide better outcomes, lower rate of complications and higher EoR compared to one-or multi-stage microscopic, non-extended endoscopic transsphenoidal, and transcranial resections