Rules, Principles and Defeasibility

La distinción entre reglas y principios presupone un criterio que no sólo permite identificarlos como tales, sino también subrayar sus diferencias. En este ensayo la noción de derrotabilidad cumplirá el papel de tal criterio. La derrotabilidad debe ser entendida como la capacidad de admitir excepciones. Las reglas, en general, poseen excepciones. Estas excepciones no pueden ser enumeradas de forma conclusiva, por cuanto las circunstancias que darán origen a casos futuros son desconocidas. En consecuencia, las reglas jurídicas siempre podrán admitir excepciones, esto es, son derrotables. Por el contrario, los principios como mandatos de optimización no admiten excepciones en ese sentido. Más bien, las circunstancias de casos futuros junto a otras condiciones, por ejemplo, la colisión entre principios, se encuentra ya implícita en el concepto de optimización y es, por tanto, esencial a la aplicación del mismo principio. Esto significa que la optimización se encuentra necesariamente relacionada con todas las circunstancias dadas. Por tanto, para aplicar un principio es preciso optimizar —y de esa forma considerar necesariamente todas las circunstancias dadas—. De ese modo, no puede surgir una excepción en la aplicación de un principio. Los principios, en otras palabras, no son derrotables. El ensayo concluye con la explicación acerca del carácter prima facie de las reglas y los principios, apelando nuevamente a la noción de derrotabilidad junto a la propuesta de una triple distinción conceptual que ofrece alguna claridad adicional en lo que al concepto de principio se refiere.Distinguishing rules and principles presupposes a criterion as a means not only to identify rules and principles but also to underscore their differences. In this essay, the notion of defeasibility will be presented as such a criterion. Defeasibility shall be understood as the capacity to accommodate exceptions. Rules, in general, have exceptions. These exceptions cannot be listed conclusively, owing to the fact that the circumstances giving rise to cases in the future are unknown. Thus, legal rules always exhibit the capacity to accommodate exceptions, that is, they are defeasible. Contrariwise, principles as optimization commands do not accommodate exceptions in this sense. Rather, the circumstances of future cases along with other conditions, for example, competing principles, are already implied in the concept of optimization and are, therefore, integral to applying the principle itself. This is to say that optimization is necessarily relative to all the circumstances at hand. Therefore, in order to apply a principle, one has to optimize —and thereby necessarily take into account all of the circumstances at hand—. There cannot, then, arise any exception in applying a principle. Principles, in other words, are not defeasible. The essay concludes with an explanation of the distinct prima facie —character of rules, and of principles, again by appeal to the notion of defeasibility, along with the proposal of a threefold conceptual distinction that offers some additional clarity where the concept of a principle is concerned—

Spülbedingungen für Tiefenfilter und deren Auswirkungen auf die Erstfiltratqualität

Ein häufig angewendetes Verfahren zur großtechnischen Aufbereitung von Trink-wasser ist die Tiefenfiltration. An die Partikelabscheidung als eine der zentralen Ver-fahrensstufen zur Aufbereitung von Trinkwasser werden besondere Anforderungen gestellt, um eine hygienisch einwandfreie Wasserqualität zu gewährleisten. So ist z. B. bei Rohwässern, die unter dem Einfluss von Oberflächenwasser stehen, vor einer abschließenden Desinfektion eine Trübung von höchstens 0,1 bis 0,2 FNU an-zustreben. Dabei ist von besonderer Relevanz, dass die innerhalb eines Filterlaufs in das Filtrat gelangende Fracht an Trübstoffen zu einem hohen Anteil zu Beginn in der sogenannten Erstfiltratphase anfällt. Ziel dieser Arbeit war es, Auswirkungen der Spülung von Tiefenfiltern auf die Erst-filtratqualität zu untersuchen und danach den Spülprozess zu optimieren. Dazu war es notwendig, die Partikelbelastung im Filtrat nach der Filterspülung zu quanti-fizieren, um Ursachen für mögliche Qualitätseinbußen beim Erstfiltrat zu erkennen. Bei der anschließenden Optimierung der Spülprozesse sollten sowohl verfahrens-technische als auch konstruktionstechnische Gesichtspunkte berücksichtigt werden. Halbtechnische Versuche konnten aufzeigen, dass die nach der Filterspülung im Überstau¬raum zurückbleibenden Partikel direkt für die erhöhte Partikelbelastung im Erstfiltrat verantwortlich sind. Um die Erstfiltratqualität zu verbessern ist es daher er-forderlich, die Partikel aus dem Überstauwasser noch vor Filtrationsstart weitest-gehend zu entfernen. Hierzu kann das Überstauwasser nach der Spülung durch Reinwasser ausgetauscht werden. Bei den meisten bestehenden Filteranlagen wäre dafür jedoch ein aufwändiger Umbau der Filteranlage notwendig. Eine Alternative stellt die Ergänzung der klassischen Filterspülung durch eine Nachspülphase mit einer Spülgeschwindigkeit unterhalb der Lockerungsgeschwindigkeit dar. Die Spül-phase mit fluidisiertem Filterbett kann dadurch verkürzt werden. Ergänzend wurde der Partikelaustrag aus dem Überstauraum während der Nach-spülphase mittels Strömungssimulation betrachtet. Dabei wurden bei den klassischen Filterkonstruktionen Totzonen bei der Durchströmung des Überstau-raums festgestellt. Während der Nachspülphase war der Austausch des Spülwassers mit einer Geschwindigkeit knapp unterhalb der Lockerungsgeschwindigkeit am besten. Beim Vergleich von verschiedenen Konstruktionen der Ablaufsysteme zeigte sich, dass mit einer innenliegenden Ablaufrinne die besten realisierbaren Werte er-reicht wurden. Die Herstellungskosten für z. B. einen Filter mit einem Durchmesser von 5.000 mm sind ca. 6 % höher als bei einer Filtertulpe. Zum Nachweis der Praxistauglichkeit wurde das im Rahmen dieser Arbeit ermittelte Spülprogramm mit einer ergänzenden Nachspülphase an einer großtechnischen Filteranlage umgesetzt. Hierdurch konnte bei ca. 6 % niedrigerem Spülwasserver-brauch der Trübungs-Peak im Erstfiltrat von 2,5 FNU auf 0,3 FNU gesenkt werden. Ein Erstfiltratabschlag war nicht mehr notwendig. Somit konnte im Rahmen dieser Arbeit u. a. gezeigt werden, dass eine deutliche Steigerung der Erstfiltratqualität auch ohne konstruktive Umbauten an der Filter-anlage erreicht werden kann

Fundamentar e decidir: crítica e reconstrução da teoria discursiva do direito de Alexy

- Divulgação dos SUMÁRIOS das obras recentemente incorporadas ao acervo da Biblioteca Ministro Oscar Saraiva do STJ. Em respeito à Lei de Direitos Autorais, não disponibilizamos a obra na íntegra.- Localização na estante: 340.132 B126

Regras, princípios e derrotabilidade

A distinção entre regras e princípios pressupõe um critério que permita não apenas identificá-los, mas também destacar as diferenças existentes entre eles. Neste ensaio, a noção de derrotabilidade será apresentada como tal critério. Derrotabilidade deve ser entendida como a capacidade de acomodar exceções. Regras, em geral, têm exceções. Essas exceções não podem ser enumeradas de forma conclusiva, pelo fato de que as circunstâncias que emergem dos casos futuros são desconhecidas. Logo, as regras de direito sempre exibem a capacidade de acomodar exceções, ou seja, elas são derrotáveis. Por outro lado, os princípios, por serem mandamentos de otimização, não acomodam, nesse sentido, exceções. Ao invés disso, as circunstâncias dos casos futuros, juntamente comoutras condições – como, por exemplo, a colisãoentre princípios –, já estão implícitas no conceito deotimização, e são, portanto, essenciais à própria aplicaçãodo princípio. Isso significa que a otimizaçãoestá necessariamente relacionada a todas as circunstânciasdadas. Assim, para se aplicar um princípio épreciso otimizar – e, dessa forma, necessariamenteconsiderar todas as circunstâncias dadas. Não pode,portanto, surgir nenhuma exceção na aplicação deum princípio. Princípios, em outras palavras, não sãoderrotáveis. O ensaio é concluído com uma explicaçãosobre a distinção entre o caráter prima facie das regrase dos princípios, novamente com recurso à noção dederrotabilidade, juntamente com a proposta de umadistinção conceitual tríplice, que torna mais clara adefinição de princípio

Wahl der Wahl: Zum andauernden Reformbedarf des Bundestagswahlrechts

Endlich wieder eine Wahlrechtsreform. Wesentlicher Anlaß dieser 22. Änderung des Bundestagswahlrechts: Die vom Bundesverfassungsgericht – wiederholt – angemahnte Vermeidung des negativen Stimmgewichts. Wesentliches Ergebnis: Nach der nächsten Wahl wird der Bundestag größer sein. Das nützt wohl nur denen, die das Gesetz beschlossen haben – den im Bundestag, hier mehr Partei als Volksvertretung, repräsentierten Parteien. Mit Ausnahme der Linken

The Impact of the Laterality on Radiographic Outcomes of the Bernese Periacetabular Osteotomy

The purpose of this study was to compare the pre and postoperative radiographic findings and analyze the complication rate with respect to the laterality in periacetabular osteotomy in right-handed surgeons. Satisfaction rate and radiographic findings were prospectively collected between 2017 and 2019 and retrospectively reviewed. For analysis, all measurements of the CT scans were performed by a musculoskeletal fellowship-trained radiologist. Complications were classified into two categories: perioperative or postoperative. All surgeries were performed by three right-hand dominant hip surgeons. A total of 41 dysplastic hips (25 right and 16 left hips) in 33 patients were included. Postoperatively, a significantly lower acetabular index angle on the left side was observed at -2.6 +/- 4.3 as compared to the right side at 1.6 +/- 6.5 (p < 0.05). The change in Center edge (CE) angle was significantly lower for the left side 13.7 +/- 5.5 degrees than on the right side, measured at 18.4 +/- 7.3 (p < 0.001); however, the overall CE angle was comparable at 38.5 +/- 8.9 degrees without any significant difference between the operated hips (left side at 37.8 +/- 6.1 degrees versus right side at 39.0 +/- 10.3; p = 0.340). No significant differences in other radiographic measurements or surgical time were observed. For complications, the right side was more commonly affected, which may also explain a higher satisfaction rate in patients who were operated on the left hip with 92.3%. The change in lateral CE angle was significantly lower for the left side and the right hip seems to be predisposed to complications, which correlate with a lower satisfaction rate in right-handed surgeons

The Impact of Hip Dysplasia on CAM Impingement

Predisposing factors for CAM-type femoroacetabular impingement (FAI) include acetabular protrusion and retroversion; however, nothing is known regarding development in dysplastic hips. The purpose of this study was to determine the correlation between CAM-type FAI and developmental dysplastic hips diagnosed using X-ray and rotational computed tomography. In this retrospective study, 52 symptomatic hips were included, with a mean age of 28.8 +/- 7.6 years. The inclusion criteria consisted of consecutive patients who suffered from symptomatic dysplastic or borderline dysplastic hips and underwent a clinical examination, conventional radiographs and rotational computed tomography. Demographics, standard measurements and the rotational alignments were recorded and analyzed between the CAM and nonCAM groups. Among the 52 patients, 19 presented with CAM impingement, whereas, in 33 patients, no signs of CAM impingement were noticed. For demographics, no significant differences between the two groups were identified. On conventional radiography, the acetabular hip index as well as the CE angle for the development of CAM impingement were significantly different compared to the nonCAM group with a CE angle of 21.0 degrees +/- 5.4 degrees vs. 23.7 degrees +/- 5.8 degrees (p = 0.050) and an acetabular hip index of 25.6 +/- 5.7 vs. 21.9 +/- 7.3 (p = 0.031), respectively. Furthermore, a crossing over sign was observed to be more common in the nonCAM group, which is contradictory to the current literature. For rotational alignment, no significant differences were observed. In dysplastic hips, the CAM-type FAI correlated to a lower CE angle and a higher acetabular hip index. In contrast to the current literature, no significant correlations to the torsional alignment or to crossing over signs were observed

Metal on Metal Bearing in Total Hip Arthroplasty and its Impact on Synovial Cell Count

Introduction: The effect of different bearings on synovial white blood cell (WBC) count and polymorphonuclear percentage (PMN%) in aspirations remains unclear. Therefore, this study investigates the impact of aseptic Metal-on-Metal (MoM) bearing on synovial fluid. Methods: We searched our arthroplasty registry for aseptic painful THAs with MoM bearings between 2011 and 2018. Then, a case-matched control group was selected with septic and aseptic Total Hip Arthroplasty (THA) with ceramic on a polyethylene (PE) bearing. The matching criteria consisted of gender, age +/-10 years, and time of aspiration (+/-2years). Periprosthetic Joint Infection (PJI) was defined according to the Infectious Diseases Society of America (IDSA), and Musculoskeletal Infection Society (MSIS) using bacterial cultures, sonication and histology. Results: In total, 19 patients who underwent hip aspiration with MoM bearing were identified. Five patients had to be excluded due to insufficient synovial fluid obtained (n = 2) or bacterial growth after sonication that was initially negative with the standard microbiological cultures (n = 3). As such, 14 were included. These patients were matched with 14 aseptic and 14 septic THAs with ceramic on a PE bearing, which constituted the control group. The mean serum chrome level was 20.0 ± 15.5 nmol/L and cobalt level 18.4 ± 22.1 nmol/L. The synovial WBC and PMN% varied significantly between MoM bearing group and the aseptic THA ceramic PE group (both p < 0.001), as well as the septic THA group (WBC p = 0.016, PMN% p < 0.001). Furthermore, the septic THA group had significantly higher CRP values than the aseptic MoM group (p = 0.016). Conclusion: MoM bearing shows significantly higher synovial WBC and PMN% when compared to aseptic THA with ceramic on PE bearing above the MSIS cut-off. This is an important consideration when diagnosing periprosthetic joint infection using the MSIS guidelines

Breakage of intramedullary femoral nailing or femoral plating: how to prevent implant failure

Introduction: Intramedullary (IM) fixation is the dominant treatment for pertrochanteric and femoral shaft fractures. In comparison to plate osteosynthesis (PO), IM fixation offers greater biomechanical stability and reduced non-union rates. Due to the minimally invasive nature, IM fixations are less prone to approach-associated complications, such as soft-tissue damage, bleeding or postoperative infection, but they are more prone to fat embolism. A rare but serious complication, however, is implant failure. Thus, the aim of this study was to identify possible risk factors for intramedullary fixation (IMF) and plate osteosynthesis (PO) failure. Materials: and methods We searched our trauma surgery database for implant failure, intramedullary and plate osteosynthesis, after proximal-pertrochanteric, subtrochanteric-or femoral shaft fractures between 2011 and 2019. Implant failures in both the IMF and PO groups were included. Demographic data, fracture type, quality of reduction, duration between initial implantation and nail or plate failure, the use of cerclages, intraoperative microbiological samples, sonication, and, if available, histology were collected. Results: A total of 24 femoral implant failures were identified: 11 IMFs and 13 POs. The average age of patients in the IM group was 68.2 +/- 13.5 years and in the PO group was 65.6 +/- 15.0 years, with men being affected in 63.6% and 39.5% of cases, respectively. A proximal femoral nail (PFN) anti-rotation was used in 7 patients, a PFN in one and a gamma nail in two patients. A total of 6 patients required cerclage wires for additional stability. A combined plate and intramedullary fixation was chosen in one patient. Initially, all intramedullary nails were statically locked. Failures were observed 34.1 weeks after the initial surgery on average. Risk factors for implant failure included the application of cerclage wires at the level of the fracture (n = 5, 21%), infection (n = 2, 8%), and the use of an additional sliding screw alongside the femoral neck screw (n = 3, 13%). In all patients, non-union was diagnosed radiographically and clinically after 6 months (n = 24, 100%). In the event of PO failure, the placement of screws within all screw holes, and interprosthetic fixation were recognised as the major causes of failure. Conclusion: Intramedullary or plate osteosynthesis remain safe and reliable procedures in the treatment of proximal femoral fractures (pertrochanteric, subtrochanteric and femoral shaft fractures). Nevertheless, the surgeon needs to be aware of several implant-related limitations causing implant breakage. These may include the application of tension band wiring which can lead to a too rigid fixation, or placement of cerclage wires at the fracture site

App-based rehabilitation program after total knee arthroplasty: a randomized controlled trial

Introduction: New app-based programs for postoperative rehabilitation have been developed, but no long-term study has been published to date. Thus, a prospective randomized control trial with 2-year follow-up was performed to evaluate the effectiveness of app-based rehabilitation (GenuSport) compared to a control group after total knee arthroplasty (TKA). Methods: Between April and October 2016, 60 patients were enrolled in the study. Twenty-five patients were lost to follow-up, leaving 35 patients undergoing TKA for inclusion. In this group, twenty patients received app-based exercise program and 15 were randomized to the control group. The mean age was 64.37 +/- 9.32 years with a mean follow-up of 23.51 +/- 1.63 months. Patients in the app group underwent an app-based knee training starting on the day of surgery; whereas, patients in the control group underwent regular physiotherapy. Functional outcome scores using the Knee Injury and Osteoarthritis Outcome Score (KOOS), Knee Society Score (KSS) and VAS of pain were analyzed. Results: In the short term, significant differences between the app group and control group in time of 10-m walk (19.66 +/- 7.80 vs. 27.08 +/- 15.46 s; p = 0.029), VAS pain at rest and activity (2.65 +/- 0.82 vs. 3.57 +/- 1.58, respectively 4.03 +/- 1.26 vs. 5.05 +/- 1.21; p < 0.05) were observed. In the long term, a variety of different tendencies was found, highest in KSS Function with 76.32 +/- 16.49 (app group) vs. 67.67 +/- 16.57 (control group) (p = 0.130). Additionally, patients in the app group required less painkillers (10.0% vs. 26.7%) and more likely to participate in sports (65.0% vs. 53.3%). Conclusions: An app-based knee trainer is a promising tool in improving functional outcomes such as KSS function score and VAS after TKA