Optical feedback and the coupling problem in semiconductor microdisk lasers

The smaller the size of a light-emitting microcavity, the more important it becomes to understand the effects of the cavity boundary on the optical mode profile. Conventional methods of laser physics, such as the paraxial approximation, become inapplicable in many of the more exotic cavity designs to be discussed here. Cavities in the shape of microdisks, pillars and rings can yield low lasing thresholds in a wide variety of gain media: quantum wells, wires and even dots, as well as quantum cascade superlattices and GaN. An overview of the experimental and theoretical status is provided, with special emphasis on the light extraction problem.Comment: PDF generated by pdflate

PENGEMBANGAN MEDIA KARTU KWARTET UNTUK MATA PELAJARAN ILMU PENGETAHUAN SOSIAL KELAS 3SD

Penelitian ini bertujuan untuk menghasilkan media kartu kwartet seri denah dan peta yang layak untuk mempermudah peserta didik dalam menghafal dan memahami kelengkapan peta pada pokok bahasan komponen denah dan peta mata pelajara Ilmu Pengetahuan Sosial kelas 3 Sekolah Dasar. Penelitian ini termasuk jenis penelitian pengembangan yang mengacu pada pengembangan Borg dan Gall. Dari 10 langkah yang dikemukakan oleh Borg dan Gall, peneliti hanya mengikuti langkah sampai pada nomor sembilan belum sampai pada tahap produksi massal. Subjek dalam penelitian ini adalah satu dosen KTP FIP, dan peserta didik tingkat sekolah dasar. Metode yang digunakan dalam mengumpulkan data adalah pengamatan langsung, wawancara, dan angket. Adapun metode yang digunakan dalam menganalisis data adalah metode deskriptif kuantitatif. Hasil pengembangan peneliti berupa media kartu kwartet pokok bahasan denah dan peta yang terdiri dari 7 kelompok kartu. Hasil validasi yang dilaksanakan oleh ahli media, segi fisik mendapatkan persentase 91,7% yang masuk dalam kategori sangat layak. segi gambar mendapatkan persentase 66,7% yang masuk dalam kategori layak. segi warna mendapatkan persentase sebesar 100% dan masuk dalam kategori sangat layak. segi tulisan dan pemakaian, oleh ahli media diberikan persentase 66,7% yang masuk dalam kategori layak. Validasi yang dilakukan oleh ahli materi, secara keseluruhan mendapatkan persentase 87,5%. Validasi per aspek dari ahli materi, pada segi isi mendapatkan presentase 86,7% yang masuk dalam kategori sangat layak. Pada segi pembelajaran mendapatkan persentase 88,9%. Dalam ujicoba dari kelompok kecil, utama, dan operasional dalam segi pembelajaran didapati kenaikan persentase dari 62,5% oleh kelompok awal, 70% dalam kelompok utama dan yang terakhir mendapatkan persentase 73% dalam kelompok operasional. Dalam segi media, media ini juga mendapatkan peningkatan presentase dari 66,7% dalam kelompok awal, kemudian 69,4% dalam kelompok utama, serta 76,9% dalam kelompok operasional. Dari hasil validasi ahli media dan ahli materi serta tahap uji coba yang dilakukan, maka media kartu kwartet ini layak digunakan untuk memudahkan peserta didik memahami materi

Effects of Fe doping in La1/2Ca1/2MnO3

The effect of Fe doping in the Mn site on the magnetic, transport and structural properties of polycrystalline La1/2Ca1/2MnO3 was studied. Doping with low Fe concentration (< 10%) strongly affects electrical transport and magnetization. Long range charge order is disrupted even for the lowest doping level studied (~2%). For Fe concentration up to 5% a ferromagnetic state develops at low temperature with metallic like conduction and thermal hysteresis. In this range, the Curie temperature decreases monotonously as a function of Fe doping. Insulating behavior and a sudden depression of the ferromagnetic state is observed by further Fe doping.Comment: 2 pages, presented at ICM2000, to appear in JMM

Mémorisation des prix par les enfants : Que nous apprennent leurs erreurs de rappel ?

Ce papier s’appuie sur des théories de cognition numérique pour étudier les erreurs de rappel de prix faites par les enfants. L’objectif est, entre autre, de souligner les caractéristiques du prix qui sont sources d’erreurs et d’analyser la structure même de ces erreurs afin de comprendre le traitement de l’information-prix chez les enfants. Les résultats révèlent que le prix est codé de multiple façon qui affecte sa mémorisation. De plus, le niveau de cherté, la terminaison et le nombre de syllabes du prix influencent les erreurs réalisées.Rappel des prix; enfant; structure des erreurs; cognition numérique; nombre à deux chiffres

Fixing the EU Democratic Deficit: An Instrumental View of Citizenship?

Introduction: One of the main contributions of sociological approaches to the academic debates about the European Union (EU) democratic deficit is to focus on the social acceptance of the EU. Nowadays, EU institutions themselves seem to share the same focus on citizens’ subjective perceptions. Indeed, fostering a sense of belonging to the EU becomes one of the strategies to fix the EU democratic deficit and strengthen its legitimacy. For EU institutions, it is necessary to bring the citizen closer to the EU as this would provide, at least partly, the solution to the democratic deficit. Hence, sociological approaches should now widen their focus, so to include the effects and adequacy of these EU policies among their research objects. Our paper aims at furthering sociological approaches by taking into account at the same time citizens’ perceptions and European institutions’ policies engaging with these representations. We argue that the vision of citizenship promoted by EU institutions through different policies is very often reduced to its instrumental dimension

Probing photoinduced spin states in spin-crossover molecules with neutron scattering

We report a neutron scattering investigation of the spin crossover compound \rm [Fe(ptz)6](BF4)2 which undergoes an abrupt thermal spin-transition from high-spin (HS) S=2 to low-spin (LS) S=0 around 135 K. The HS magnetic state can be restored at low temperature under blue/green light irradiation. We have developed a specially designed optical setup for neutron scattering to address the magnetic properties of the light-induced HS state. By using neutron diffraction, we demonstrate that significant HS/LS ratios (of up to 60 \%) can be obtained with this experimental setup on a sample volume considered large (400 mg), while a complete recovery of the LS state is achieved using near infrared light. With inelastic neutron scattering (INS) we have observed, for the first time in a photo-induced phase, magnetic transitions arising from the metastable HS S=2 state split by crystal field and spin-orbit coupling. We interpret the INS data assuming a spin-only model with a zero-field splitting (ZFS) of the S=2 ground state. The obtained parameters are D \approx -1.28 \pm 0.03 meV and |E| \approx 0.08 \pm 0.03 meV. The present results show that in situ magnetic inelastic neutron scattering investigations on a broad range of photomagnetic materials are now possible

METODE PROYEK DALAM MENINGKATKAN KETERAMPILAN PRA VOKASIONAL MEMBUAT TEMPE PADA ANAK TUNANETRA SMPLB

Abstract : Pre vocational skill was a work skill needed as wisdom to support life necessity to reach autonomy. Blind children required pre vocational skill because blind children had disturbance toward their visual so that the children should obtain training first in doing a job. In this case, pre vocational skill of making tempe was given by using project method. The purpose of this research was to enhance the result of pre vocational skill of making tempe by using project method to blind children in SMPLB-A YPAB Surabaya.The research used pre experiment kind of research with &ldquo;one shot case study&rdquo; design. The method used to collect the data was test. To analyze the data it was used analysis technique of statistic non parametric.The students&rsquo; daily value for the average was 65 then they were given intervention 6 times, once repeating material. The students were then given post test (primer data) with average value, 90. Daily average value (secondary data) and post test (primer data) indicated that the students&rsquo; value changed to be better. From the data analysis result it was concluded that couting number from ZH was 2,05. The number was then compared with critic value 5% ZH=1,96. The result showed ZH &gt; 1,96 which meant that Ho was refused. Ho was resufed that meant Ha was accepted so that it chould be said that &ldquo;there was significant enhancement of pre vocational skill of making tempe to blind student in SMPLB-A the eighth class by using project method.Based on the analysis data result it could be stated that the project method could enhance pre vocational skill of making tempe to blind students in the eighth class of SMPLB-A.Keyword: Project Method, Pre Vocational Skill To Make Temp

Connaissance du prix par les enfants de 5 à 13 ans : une étude exploratoire

At a very early age, the child becomes a real consumer and the prices becomes part of his daily basis. This exploratory study shows that the child acquires a knowledge of prices through a non linear and non cumulative training, marked out by formative incidents. He uses measures and strategies of price evaluation. This procedure is influenced by interest, expertise and experience of children product.child-consumer; price konwoledge; memorization and estimation of prices

Atrial Fibrillation in Dengue Infection: A Self-limiting Phenomenon? (Two Case Reports)

Dengue fever (DF) is highly prevalent in Indonesia as evidenced by 129,650 cases in 2015.Atrial fibrillation (AF) in dengue is exceptionally rare and usually self-limiting with resolution after recovery of illness. The aim of this case report is to depict two patients with AF in DF which resolves spontaneously in one and persists after infection in the other. Case 1 was 50 years old male presented with fever since 4 days before admission. NS1 antigen and IgM anti-Dengue virus were positive. An electrocardiogram (ECG) showed AF with rapid ventricular response (AFRVR). Case 2 was 53 years old male presented with dyspnea and palpitations 1 hour before admission. Patient had fever since 5 days before admission. Laboratory exams showed leukopenia, thrombocytopenia and positive IgM anti-Dengue virus. An electrocardiogram showed AFRVR. Intravenous fluids (normal saline), paracetamol, and digoxin were administered in both patients. They were admitted for close monitoring. Pre-discharge ECG of Case 1 showed resolution of AF. However, in Case 2, AF persists in pre-discharge ECG. In conclusion, physicians should be aware that a potentially reversible atrial fibrillation might be caused by this infection. It should be ensured that in those persisting cases, they should not be dismissed as just an ‘irreversible’ AF and progress into full-blown heart failure

Anisotropic Topological Hall Effect with Real and Momentum Space Berry Curvature in the Antiskrymion Hosting Heusler Compound Mn1.4_{1.4}PtSn

The topological Hall effect (THE) is one of the key signatures of topologically non-trivial magnetic spin textures, wherein electrons feel an additional transverse voltage to the applied current. The magnitude of THE is often small compared to the anomalous Hall effect. Here, we find a large THE of 0.9 $\mu\Omega$cm that is of the same order of the anomalous Hall effect in the single crystalline antiskyrmion hosting Heusler compound Mn$_{1.4}$PtSn, a non-centrosymmetric tetragonal compound. The THE is highly anisotropic and survives in the whole temperature range where the spin structure is noncoplanar (<170 K). The THE is zero above the spin reorientation transition temperature of 170 K, where the magnetization will have a collinear and ferromagnetic alignment. The large value of the THE entails a significant contribution from the momentum space Berry curvature along with real space Berry curvature, which has never been observed earlier