The School Principal and Teacher Retention

This report comes from the MERC Teacher Retention study. This study was designed to identify patterns of teacher retention in the MERC region and to determine the school and system-level factors driving them. The study also provides an overview of state and regional policies and programs relevant to teacher retention, and includes evaluations of existing policies and initiatives to determine efficacy and cost benefit. This policy brief examines the role of leadership, and specifically the school principal, in retaining teachers. The brief includes a review of studies that used survey scales to measure leadership and then disaggregate and re-aggregate the items in those scales into a handful of common themes. The purpose of this policy brief is to review the foundational literature on the role of the principal in order to develop a set of focus areas for principals who want to improve teacher retention

Nanoladder cantilevers made from diamond and silicon

We present a "nanoladder" geometry that minimizes the mechanical dissipation of ultrasensitive cantilevers. A nanoladder cantilever consists of a lithographically patterned scaffold of rails and rungs with feature size $\sim$ 100 nm. Compared to a rectangular beam of the same dimensions, the mass and spring constant of a nanoladder are each reduced by roughly two orders of magnitude. We demonstrate a low force noise of $158 (+62)(-42)\,$zN and $190 (+42)(-33)\,$zN in a one-Hz bandwidth for devices made from silicon and diamond, respectively, measured at temperatures between 100--150 mK. As opposed to bottom-up mechanical resonators like nanowires or nanotubes, nanoladder cantilevers can be batch-fabricated using standard lithography, which is a critical factor for applications in scanning force microscopy

A European spine registry

Abstract.: New joint replacement registries are being widely implemented across national and international organizations. The need for a continuous long-term post-market surveillance of implants has been recognized, and has become increasingly important to ensure the quality of prosthetic components. Registry data with large case numbers represent an acceptable alternative to controlled randomized clinical trials, which are often difficult to conduct in orthopedic surgery. The variety of implants and procedures in spinal surgery not only induces the same need for long-term monitoring of post-surgical product performance as in the joint replacement subspecialties, but also renders essential the establishment of a comprehensive spine registry for all major pathologies and interventions. In cooperation with the M.E. Müller Institute for Evaluative Research in Orthopedic Surgery (MEM-CED) at the University of Berne, Switzerland, the Spine Society of Europe (SSE) has launched Spine Tango: the first modular and multilevel European online registry for spinal surgery. Within Spine Tango, the major challenge in registry design and structure is the definition of and agreement upon a core set of questions as a common European dataset. Additional questions for national or individual interest can also be dynamically added to the core dataset. An automated implant tracking system has also been setup, which allows highly precise product documentation without additional work for clinical staff member

Development of a German version of the Oswestry Disability Index. Part 1: cross-cultural adaptation, reliability, and validity

Patient-orientated assessment methods are of paramount importance in the evaluation of treatment outcome. The Oswestry Disability Index (ODI) is one of the condition-specific questionnaires recommended for use with back pain patients. To date, no German version has been published in the peer-reviewed literature. A cross-cultural adaptation of the ODI for the German language was carried out, according to established guidelines. One hundred patients with chronic low-back pain (35 conservative, 65 surgical) completed a questionnaire booklet containing the newly translated ODI, along with a 0-10 pain visual analogue scale (VAS), the Roland Morris Disability Questionnaire, and Likert scales for disability, medication intake and pain frequency [to assess ODI's construct (convergent) validity]. Thirty-nine of these patients completed a second questionnaire within 2weeks (to assess test-retest reliability). The intraclass correlation coefficient for the test-retest reliability of the questionnaire was 0.96. In test-retest, 74% of the individual questions were answered identically, and 21% just one grade higher or lower. The standard error of measurement (SEM) was 3.4, giving a "minimum detectable change” (MDC95%) for the ODI of approximately 9 points, i.e. the minimum change in an individual's score required to be considered "real change” (with 95% confidence) over and above measurement error. The ODI scores correlated with VAS pain intensity (r=0.78, P<0.001) and Roland Morris scores (r=0.80, P<0.001). The mean baseline ODI scores differed significantly between the surgical and conservative patients (P<0.001), and between the different categories of the Likert scales for disability, medication use and pain frequency (in each case P<0.001). Our German version of the Oswestry questionnaire is reliable and valid, and shows psychometric characteristics as good as, if not better than, the original English version. It should represent a valuable tool for use in future patient-orientated outcome studies in German-speaking land

Development of a German version of the Oswestry Disability Index. Part 2: sensitivity to change after spinal surgery

When functional scales are to be used as treatment outcome measures, it is essential to know how responsive they are to clinical change. This information is essential not only for clinical decision-making, but also for the determination of sample size in clinical trials. The present study examined the responsiveness of a German version of the Oswestry Disability Index version 2.1 (ODI) after surgical treatment for low back pain. Before spine surgery 63 patients completed a questionnaire booklet containing the ODI, along with a 0-10 pain visual analogue scale (VAS), the Roland Morris disability questionnaire, and Likert scales for disability, medication intake and pain frequency. Six months after surgery, 57 (90%) patients completed the same questionnaire booklet and also answered Likert-scale questions on the global result of surgery, and on improvements in pain and disability. Both the effect size for the ODI change score 6months after surgery (0.87) and the area under the receiver operating characteristics (ROC) curve for the relative improvement in ODI score in relation to global outcome 6months after surgery (0.90) indicated that the ODI showed good responsiveness. The ROC method revealed that a minimum reduction of the baseline (pre-surgery) ODI score by 18% (equal to a mean 8-point reduction in this patient group) represented the cut-off for indicating a "good” individual outcome 6months after surgery (sensitivity 91.4% and specificity 82.4%). The German version of the ODI is a sensitive instrument for detecting clinical change after spinal surgery. Individual improvements after surgery of at least an 18% reduction on baseline values are associated with a good outcome. This figure can be used as a reliable guide for the determination of sample size in future clinical trials of spinal surger

SSE Spine Tango - content, workflow, set-up: www.eurospine.org - Spine Tango

The Spine Tango registry is now accessible via the SSE webpage under www.eurospine.org - Spine Tango. Links to the Swiss/International, German and Austrian modules are provided as well as information about the philosophy, methodology and content. Following the links, the users are taken to the respective national modules for registration or log-in and data entry. The Swiss/International module, also accessible under www.spinetango.com, is used by all Swiss and international users, who do not have a separate national module. The physician administered forms for surgery, staged surgery and follow-up can be downloaded as PDFs.The officially recommended Spine Tango patient forms are also available. All forms were implemented in an online version and as scannable optical mark reader forms which can be ordered from the corresponding autho

Contribution of picoplankton to the total particulate organic carbon (POC) concentration in the eastern South Pacific

International audienceProchlorococcus, Synechococcus, picophytoeukaryotes and bacterioplankton abundances and contributions to the total particulate organic carbon concentration (POC), derived from the total particle beam attenuation coefficient (cp), were determined across the eastern South Pacific between the Marquesas Islands and the coast of Chile. All flow cytometrically derived abundances decreased towards the hyper-oligotrophic centre of the gyre and were highest at the coast, except for Prochlorococcus, which is not detected under eutrophic conditions. Temperature and nutrient availability appeared important in modulating picophytoplankton abundance, according to the prevailing trophic conditions. Although the non-vegetal particles tended to dominate the cp signal everywhere along the transect (50 to 83%), this dominance seemed to weaken from oligo- to eutrophic conditions, the contributions by vegetal and non-vegetal particles being about equal under mature upwelling conditions. Spatial variability in the vegetal compartment was more important than the non-vegetal one in shaping the water column particulate attenuation coefficient. Spatial variability in picophytoplankton biomass could be traced by changes in both Tchla and cp. Finally, picophytoeukaryotes contributed with ~38% on average to the total integrated phytoplankton carbon biomass or vegetal attenuation signal along the transect, as determined by direct size measurements on cells sorted by flow cytometry and optical theory. The role of picophytoeukaryotes in carbon and energy flow would therefore be very important, even under hyper-oligotrophic conditions

Probing two topological surface bands of Sb2Te3 by spin-polarized photoemission spectroscopy

Using high resolution spin- and angle-resolved photoemission spectroscopy, we map the electronic structure and spin texture of the surface states of the topological insulator Sb2Te3. In combination with density functional calculations (DFT), we directly show that Sb2Te3 exhibits a partially occupied, single spin-Dirac cone around the Fermi energy, which is topologically protected. DFT obtains a spin polarization of the occupied Dirac cone states of 80-90%, which is in reasonable agreement with the experimental data after careful background subtraction. Furthermore, we observe a strongly spin-orbit split surface band at lower energy. This state is found at 0.8eV below the Fermi level at the gamma-point, disperses upwards, and disappears at about 0.4eV below the Fermi level into two different bulk bands. Along the gamma-K direction, the band is located within a spin-orbit gap. According to an argument given by Pendry and Gurman in 1975, such a gap must contain a surface state, if it is located away from the high symmetry points of the Brillouin zone. Thus, the novel spin-split state is protected by symmetry, too.Comment: 8 pages, 10 figure

Contribution of picoplankton to the total particulate organic carbon concentration in the eastern South Pacific

International audienceProchlorococcus, Synechococcus, picophytoeukaryotes and bacterioplankton abundances and contributions to the total particulate organic carbon concentration, derived from the total particle beam attenuation coefficient (cp), were determined across the eastern South Pacific between the Marquesas Islands and the coast of Chile. All flow cytometrically derived abundances decreased towards the hyper-oligotrophic centre of the gyre and were highest at the coast, except for Prochlorococcus, which was not detected under eutrophic conditions. Temperature and nutrient availability appeared important in modulating picophytoplankton abundance, according to the prevailing trophic conditions. Although the non-vegetal particles tended to dominate the cp signal everywhere along the transect (50 to 83%), this dominance seemed to weaken from oligo- to eutrophic conditions, the contributions by vegetal and non-vegetal particles being about equal under mature upwelling conditions. Spatial variability in the vegetal compartment was more important than the non-vegetal one in shaping the water column particle beam attenuation coefficient. Spatial variability in picophytoplankton biomass could be traced by changes in both total chlorophyll a (i.e. mono + divinyl chlorophyll a) concentration and cp. Finally, picophytoeukaryotes contributed ~38% on average to the total integrated phytoplankton carbon biomass or vegetal attenuation signal along the transect, as determined by size measurements (i.e. equivalent spherical diameter) on cells sorted by flow cytometry and optical theory. Although there are some uncertainties associated with these estimates, the new approach used in this work further supports the idea that picophytoeukaryotes play a dominant role in carbon cycling in the upper open ocean, even under hyper-oligotrophic conditions