Native chick laminin-4 containing the beta 2 chain (s-laminin) promotes motor axon growth.

After denervation of muscle, motor axons reinnervate original synaptic sites. A recombinant fragment of the synapse specific laminin beta 2 chain (s-laminin) was reported to inhibit motor axon growth. Consequently, a specific sequence (leucine-arginine-glutamate, LRE) of the laminin beta 2 chain was proposed to act as a stop signal and to mediate specific reinnervation at the neuromuscular junction (Porter, B.E., J. Weis, and J.R. Sanes. 1995. Neuron. 14:549-559). We demonstrate here that native chick laminin-4, which contains the beta 2 chain and is present in the synaptic basement membrane, does not inhibit but rather promotes motor axon growth. In native heterotrimeric laminin, the LRE sequence of the beta 2 chain is found in a triple coiled-coil region that is formed by all three subunits. We show here that the effect of LRE depends on the structural context. Whereas a recombinant randomly coiled LRE peptide indeed inhibited outgrowth by chick motoneurons, a small recombinant triple coiled-coil protein containing this sequence did not

Bose-Einstein Condensates in Strongly Disordered Traps

A Bose-Einstein condensate in an external potential consisting of a superposition of a harmonic and a random potential is considered theoretically. From a semi-quantitative analysis we find the size, shape and excitation energy as a function of the disorder strength. For positive scattering length and sufficiently strong disorder the condensate decays into fragments each of the size of the Larkin length ${\cal L}$. This state is stable over a large range of particle numbers. The frequency of the breathing mode scales as $1/{\cal L}^2$. For negative scattering length a condensate of size ${\cal L}$ may exist as a metastable state. These finding are generalized to anisotropic traps

Two heads are better than one: The association between condom decision-making and condom use errors and problems

This is an open access article - Copyright @ 2008 BMJ Publishing GroupObjectives: This exploratory study compared the frequency of condom use errors and problems between men reporting that condom use for penile–vaginal sex was a mutual decision compared with men making the decision unilaterally. Methods: Nearly 2000 people completed a web-based questionnaire. A sub-sample of 660 men reporting that they last used a condom for penile–vaginal sex (within the past three months) was analysed. Nine condom use errors/problems were assessed. Multivariate analyses controlled for men’s age, marital status, and level of experience using condoms. Results: Men’s unilateral decision-making was associated with increased odds of removing condoms before sex ended (adjusted odds ratio (AOR) 2.51, p=0.002), breakage (AOR 3.90, p=0.037), and slippage during withdrawal (AOR 2.04, p=0.019). Men’s self-reported level of experience using condoms was significantly associated with seven out of nine errors/problems, with those indicating less experience consistently reporting more errors/problems. Conclusions: Findings suggest that female involvement in the decision to use condoms for penile–vaginal sex may be partly protective against some condom errors/problems. Men’s self-reported level of experience using condoms may be a useful indicator of the need for education designed to promote the correct use of condoms. Education programmes may benefit men by urging them to involve their female partner in condom use decisions.Funding for this project was provided by the Canada Research Chair in Social Justice and Sexual Health at the University of Windsor, and the Rural Center for AIDS/STD Prevention and The Kinsey Institute for Research in Sex, Gender, and Reproduction at Indiana University

Pengaruh Kepemimpinan Kepala Sekolah dan Kompetensi Guru terhadap Motivasi Kerja Guru Serta Implikasinya pada Kinerja Guru di SMP Negeri Kota Palembang

Penelitian ini bertujuan untuk menganalisis dan mengetahui Pengaruh Kepemimpinan Kepala Sekolah dan Kompetensi Guru Terhadap Motivasi Kerja Guru Serta Implikasinya Pada Kinerja Gurudi SMP Negeri Kota Palembang.Populasi dalam penelitian ini berjumlah sebesar 2668 guru SMPN Kota Palembang,sedangkan sampel 340 guru sesuai persyaratan SEM.Analisis hasil penelitian menggunakan metode statistik deskriptif dan inferensial untuk menyimpulkan adanya pengaruh variabel eksogen terhadap variabel endogen baik secara simultan maupun parsial. Model analisis menggunakan Structure Equation Model (SEM) dengan komposisi sub-struktur :Kepemimpinan kepala sekolah (X1) dan kompetensi guru (X2) sebagai variabel eksogen dan Motivasi Kerja (Y) sebagai variabel endogen . Struktur 2 terdiri dari : Kepemimpinan kepala sekolah (X1), Kompetensi guru (X2), dan Motivasi Kerja guru(Y) sebagai variabel eksogen dan Kinerja Guru(Z) sebagai variabel endogen.Hasil penelitian menunjukkan sebagai berikut :(1) Secara parsial terdapat pengaruh positif dan signifikan kepemimpinan kepala sekolah terhadap motivasi kerja guru di SMP Negeri kota Palembang,(2) Secara parsial terdapat pengaruh positif dan signifikan kompetensi guru terhadapmotivasi kerja guru di SMP Negeri kota Palembang,(3)Terdapat pengaruh positif kepemimpinan kepala sekolah dan kompetensi guru secara bersama-sama terhadap motivasi kerja guru di SMP Negeri kota Palembang, (4) Secara parsial terdapat pengaruh positif dan signifikan motivasi kerja terhadap kinerja guru di SMP Negeri kota Palembang,(5) Secara parsial terdapat pengaruh positif dan signifikan kepemimpinan kepala sekolah terhadap kinerja guru di SMP Negeri kota Palembang,(6) Secara parsial terdapat pengaruh positif dan signifikan kompetensi guru terhadap kinerja guru di SMP Negeri kota Palembang,(7) Terdapat pengaruh positif kepemimpinan kepala sekolah, kompetensi guru dan motivasi kerja guru secara bersama-sama terhadap kinerja guru di SMP Negeri kota Palembang. Hasil penelitian ini menggambarkan bahwa untuk meningkatkan kinerja guru SMPN Kota Palembang maka perlu lebih meningkatkan kompetensi guru .Sedangkan untuk meningkatkan motivasi kerja guru SMPN Kota Palembang, faktor kepemimpinan kepala sekolah memiliki peran yang paling besar.Kata Kunci : Kepemimpinan Kepala Sekolah, Kompetensi, Motivasi Kerja, dan Kinerj

Dissolution dominating calcification process in polar pteropods close to the point of aragonite undersaturation

Thecosome pteropods are abundant upper-ocean zooplankton that build aragonite shells. Ocean acidification results in the lowering of aragonite saturation levels in the surface layers, and several incubation studies have shown that rates of calcification in these organisms decrease as a result. This study provides a weight-specific net calcification rate function for thecosome pteropods that includes both rates of dissolution and calcification over a range of plausible future aragonite saturation states (Omega_Ar). We measured gross dissolution in the pteropod Limacina helicina antarctica in the Scotia Sea (Southern Ocean) by incubating living specimens across a range of aragonite saturation states for a maximum of 14 days. Specimens started dissolving almost immediately upon exposure to undersaturated conditions (Omega_Ar,0.8), losing 1.4% of shell mass per day. The observed rate of gross dissolution was different from that predicted by rate law kinetics of aragonite dissolution, in being higher at Var levels slightly above 1 and lower at Omega_Ar levels of between 1 and 0.8. This indicates that shell mass is affected by even transitional levels of saturation, but there is, nevertheless, some partial means of protection for shells when in undersaturated conditions. A function for gross dissolution against Var derived from the present observations was compared to a function for gross calcification derived by a different study, and showed that dissolution became the dominating process even at Omega_Ar levels close to 1, with net shell growth ceasing at an Omega_Ar of 1.03. Gross dissolution increasingly dominated net change in shell mass as saturation levels decreased below 1. As well as influencing their viability, such dissolution of pteropod shells in the surface layers will result in slower sinking velocities and decreased carbon and carbonate fluxes to the deep ocean

Overcoming Assessment Challenges - Tipping the Balance

It is well known to primary teachers that effective assessment of children requires a multi-faceted approach (Sparks Linfield 1994). Equally, written feedback on a piece of work is often not understood by the pupils themselves (Sparks Linfield 1995). As one proceeds through secondary and tertiary education, this situation changes little, with the best attempts to set ‘perfect' assessments still leading to misinterpretation by students. It is also true that students often do not always recognise what is meant by the term ‘feedback' and have difficulty in interpreting and understanding the feedback that they receive, even with the most careful and targeted advice in advance. (Sutcliffe et al 2014) In 2010 the National Union of Students released a ‘Charter for Assessment and Feedback' which outlined ten principles for effective assessment and feedback. Despite this charter, the National Student Survey (NSS) in 2014 still showed twenty-eight percent of students were not satisfied. ‘Assessment and feedback was again rated the lowest by students, with just seventy-two percent saying they were satisfied with this, the same level as last year.' (Grove 2014) This poster considers research carried out in 2014 when the Year 2 cohort of students on a Bachelor of Arts Primary Education course were asked to complete a questionnaire inviting views on feedback on assessment they found most helpful in clarifying things they did not understand. Analysis of completed questionnaires revealed that although students' experiences of feedback and assessment within their first year of study had broadly matched the principles outlined within the NUS Charter, twenty-five percent of students still were not satisfied. Results from the cohort showed a desire for a range of types of feedback including a wish for face-to-face discussion to enable them to both assess their understanding of feedback comments and feed-forward actions. In addition, a common theme emerged: a lack of perception by students of their own roles and responsibilities within the assessment/feedback cycle. Recommendations are made for ways to overcome the challenge to provide assessment feedback that aims to give total satisfaction