The Nature of Online Charter Schools: Evolution and Emerging Concerns

Online charter schools are unique among K-12 online learning options for students. They are full-time, public schools that combine online learning with traditional and home schooling practices. They are often chartered by a state agency, supported in full or in part with state funds and most often managed by a private educational management company. Some extol the virtues of these schools as being able to reach unique student populations at a fraction of the cost borne by traditional public school education. Others are concerned over the lack of evidence supporting the effectiveness of these schools and the problems encountered by young learners who are separated from their teachers due to the online nature of learning in this environment. The goal of this literature review is to: (a) provide a definition of online charter schools; (b) describe their evolution and current status; (c) describe their operations; and, (d) to reveal emerging concerns, including governance, funding and effectiveness. Finally, the authors conclude that there are three significant gaps found in the literature concerning online charter schools and provide recommendations for further research

Warum rauchen Schizophreniepatienten?

Zusammenfassung: Patienten mit schizophrenen Störungen zeigen eine erhöhte Prävalenz der Nikotinabhängigkeit. Diese Arbeit beleuchtet die Zusammenhänge zwischen Schizophrenie und Nikotinkonsum. Es gibt deutliche Hinweise dafür, dass wesentliche Bereiche kognitiver Funktionen bei Patienten mit schizophrenen Erkrankungen durch Nikotin verbessert werden, insbesondere Daueraufmerksamkeit, gerichtete Aufmerksamkeit, Arbeitsgedächtnis, Kurzzeitgedächtnis und Wiedergabe aus dem Gedächtnis. Auch konnten in einigen Studien mittels ereigniskorrelierten Potenzialen (P50-Paradigma) und der Präpulsinhibition des akustisch ausgelösten Schreckreflexes gezeigt werden, dass präattentive Maße der Informationsverarbeitung, die eine zentrale Rolle in der Schizophrenie spielen, durch Gabe von Nikotin verbessert werden können. Weiterhin kann Rauchen die durch antipsychotische Medikamente hervorgerufenen extrapyramidalen Nebenwirkungen verbessern, und es induziert das Zytochrom P4501A2, das auch an der Metabolisierung einiger Neuroleptika beteiligt ist. Zusammenfassend kann festgestellt werden, dass die Nikotinzufuhr bei Patienten mit schizophrenen Störungen eine Form der "Selbstmedikation" darstellen könnte, um Defizite im Bereich Aufmerksamkeit, Kognition und Informationsverarbeitung zu verbessern und um Nebenwirkungen von Antipsychotika zu reduzieren. Mögliche pharmakotherapeutische Ansätze zur Behandlung der gestörten Neurotransmission am nikotinergen Azetylcholinrezeptor werden diskutier

Non-operatively managed small to medium-sized subscapularis tendon tears: MRI evaluation with a minimum of 5 years follow-up

Background Isolated or combined subscapularis (SSC) tendon tears are frequently found in patients with shoulder pain. The purpose of this study was to evaluate the structural changes associated with SSC tear in a consecutive series of patients with nonoperatively treated small size to midsize SSC tendon tears using magnetic resonance imaging (MRI). Methods In this retrospective case series, all patients with an isolated or combined SSC tendon tear treated nonoperatively between 1999 and 2019 were identified from our MRI and clinical databases. Twenty-one patients with a mean age of 52.6 years (range 26.6-64.8, standard deviation 9.3) with a second MRI scan at a minimum of 5 years of follow-up were enrolled. The mean follow-up was 8.6 years (range 5.6-12.6, standard deviation 1.8). Initial and last follow-up MRI scans were used to determine concomitant cuff lesions, size of the SSC tear, fatty infiltration of the SSC muscle, and biceps pathology. Results Five patients had an isolated SSC lesion; 7 patients had a concomitant tear of the supraspinatus, and 9 patients had a supraspinatus and anterior infraspinatus tendon tear. At diagnosis, 14 patients had a type 1 SSC lesion as classified by Lafosse et al, 4 patients had type 2, and 3 patients had type 3 lesions. Nineteen patients (90%) were found to have an SSC tear progression of at least one Lafosse grade (P < .001); however, no tear had progressed to an irreparable type lesion (defined as Lafosse type 5). In addition, the size of SSC tendon tears increased significantly from 75 mm2 to 228 mm2 (P < .001). At the final MRI scan, the grading of fatty infiltration increased by 1 grade in 4 cases and by 2 grades in 4 cases (P = .042). At the final follow-up, in eight patients, the condition of the long head of biceps tendon was unchanged from the initial MRI; in nine patients, there was a newly subluxated biceps tendon, and in 6 patients, there was a newly ruptured long head of biceps tendon (P < .001). Conclusion After a mean of 8.6 years, almost all nonoperatively treated SSC tendon tears had increased in size, but only one-third showed additional progression of muscle fatty degeneration on MRI scan. None of the SSC lesions became irreparable during the observation period

Response to the letter by Udo Bonnet

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153273/1/nmo13715_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153273/2/nmo13715.pd

Traumatic brain injury in the elderly after a skiing accident: A retrospective cohort study in a level 1 emergency department in Switzerland.

BACKGROUND Skiing is a very popular sport worldwide, with increasing trends over the past decades. This study aimed to evaluate the importance of traumatic brain injury (TBI), especially in the elderly, after a ski accident, and to describe its short-term repercussions. METHODOLOGY Patients were analyzed who were admitted to our neurotrauma center from 2012-2018 after a head trauma while skiing. Three different age groups were differentiated and analyzed for the severity of TBI depending on the initial Glasgow Coma Scale as the primary outcome and as secondary outcomes need and type of surgery, Glasgow Outcome Score, preexisting use of anticoagulant or antiplatelet drugs, time to presentation, and pattern of brain injury. TBI severity was adjusted to the time to initial medical consultation. RESULTS No significant difference in TBI severity was found when comparing the middle (>29-54) and older (≥54) age groups to the reference group <30 years (OR:0.45, p = 0.127; OR:0.46, p = 0.17). Acute subdural hemorrhage was present in 21.2% of the ≥55 group and 14.5% of the 30-54 age group, compared to 12.8% of the youngest group (p = <0.001). Overall, 39.4% of the patients in the ≥55 group and 8.1% of the 30-54 age group presented with chronic subdural hemorrhage, whereas none of the youngest patients did (p = <0.001). CONCLUSION No differences were observed in terms of TBI severity between age groups after acute trauma. Nonetheless, a different pattern of head injury after TBI in older patients was demonstrated. Accordingly, the management differs for these TBIs compared to those of younger patients

Исследование влияния температуры на процесс восстановления ацетилдифенила изопропилатом алюминия

We present a compact module, emitting nearly diffraction limited green laser light at 531 nm at an average output power of more than 500 mW. As pump source for the second harmonic generation a DBR tapered laser with a total length of 6 mm was used. The RW section had a length of 2 mm including a 1 mm long passive DBR section. The devices were mounted p-side up on a copper block. For this mounting scheme, the device reaches up to 7 W maximal output power. At the power level of about 3.8 W used in the presented experiment, a wavelength of 1062.6 nm with a line-width below 0.02 nm (FWHM) was determined. More than 80% of the emitted power is originated within the central lobe of the beam waist profile illustrating the nearly diffraction limited beam quality. Using a 30mm long MgO-doped periodically poled LiNbO3 bulk crystal, the second harmonic wave is generated in a single-pass setup. Due to precise alignment and beam shaping based on the results of numerical simulations and a properly temperature control of the PPLN crystal, a maximum optical conversion efficiency of more than 14% (3.7%/W) was achieved. The fluctuation of the output power is far below 1%

Do alpine skiers and snowboarders wear protective equipment more often after an accident?

Questions under study/principles: Analysis of changes in the behaviour of wearing protective equipment by alpine skiers and snowboarders after injury, performed at a level I trauma centre in Switzerland. Methods: We present a study, using a standardised questionnaire, assessing behaviour on ski slopes by adult patients admitted between Oct 2007 and April 2008. Patients were re-interviewed after the 2008/2009 season. McNemar tests were used to analyse differences in protective clothing wearing rates between the two seasons. Multiple logistic regression with age, gender and injury severity score (ISS) as predictors, was used to compare findings in those who started wearing protective equipment and those who did not. Results: A total of 104/132 patients from the 2007/2008 season were questioned about wearing protective equipment in 2008/2009. 20 patients could not be reassessed (7 declined, 13 had abandoned winter sports). A total of 84 patients were reassessed (61 alpine skiers and 23 snowboarders). The median age of participants was 39 years and 70.2% were male. Helmet and back protector wearing rates increased from 40.5% to 78.6% (p <0.001) and from 14.3% to 23.8% (p = 0.021), respectively. Snowboarders more than doubled their helmet wearing rate (39.1% to 82.6%, p = 0.002). Skiers showed a trend towards doubling their back protector wearing rate (6.6% to 14.8%, p = 0.063). Younger skiers started wearing back protectors more often than older skiers. Conclusions: Sustained injury might provide skiers and snowboards with a potent trigger to change their attitude towards the use of protective equipment. The psychological processes influencing the use of protective equipment require further investigation

Cluster synchronization in three-dimensional lattices of diffusively coupled oscillators

Cluster synchronization modes of continuous time oscillators that are diffusively coupled in a three-dimensional (3-D) lattice are studied in the paper via the corresponding linear invariant manifolds. Depending in an essential way on the number of oscillators composing the lattice in three volume directions, the set of possible regimes of spatiotemporal synchronization is examined. Sufficient conditions of the stability of cluster synchronization are obtained analytically for a wide class of coupled dynamical systems with complicated individual behavior. Dependence of the necessary coupling strengths for the onset of global synchronization on the number of oscillators in each lattice direction is discussed and an approximative formula is proposed. The appearance and order of stabilization of the cluster synchronization modes with increasing coupling between the oscillators are revealed for 2-D and 3-D lattices of coupled Lur'e systems and of coupled Rossler oscillators

Factors influencing brightness and beam quality of conventional and distributed Bragg reflector tapered laser diodes in absence of self-heating

In this study, the authors examine some of the factors affecting the brightness and the beam quality of high-power tapered lasers. The large volume resonators required to achieve a high-power, high-brightness operation make the beam quality sensitive to carrier lensing and a multimode operation. These cause bleaching of the regions outside the ridge waveguide. The beam quality in the conventional and the distributed Bragg reflector tapered lasers is examined in the absence of the self-heating effects to investigate the effect of the carrier lensing effects. The influence of the front facet reflectivity and the taper angle on the beam quality is investigated. The beam quality was found to degrade with an increase in the front facet reflectivity and for the larger taper angles in the conventional tapered lasers, especially at low ridge waveguide currents. Finally, the performance of the conventional tapered lasers employing a beamspoiler was assessed. The beam quality was found to be comparable with that achieved in the DBR tapered lasers