Parametrically excited "Scars" in Bose-Einstein condensates

Parametric excitation of a Bose-Einstein condensate (BEC) can be realized by periodically changing the interaction strength between the atoms. Above some threshold strength, this excitation modulates the condensate density. We show that when the condensate is trapped in a potential well of irregular shape, density waves can be strongly concentrated ("scarred") along the shortest periodic orbits of a classical particle moving within the confining potential. While single-particle wave functions of systems whose classical counterpart is chaotic may exhibit rich scarring patterns, in BEC, we show that nonlinear effects select mainly those scars that are locally described by stripes. Typically, these are the scars associated with self retracing periodic orbits that do not cross themselves in real space. Dephasing enhances this behavior by reducing the nonlocal effect of interference

STUDYING HERBICIDE RESISTANCE USING TREATMENT AREA DYNAMICS MODEL

Repeated use of a herbicide or herbicides with the same mode of action on a particular crop over a number of years may cause the selection of herbicide resistant weed populations. As a result effective weed control is lost which can seriously affect crop yield and quality. The selection of herbicide resistant weed populations is a concern not only for crop-growers, but also the manufacturers of the affected herbicides. In the present paper a two-step procedure is developed to identify the herbicide resistant activity in a particular crop growing region by estimating the resistant areas (in acres/hectares) in a given year of herbicide continued treatment along with percent risk of detecting herbicide resistance. A computer aided treatment area dynamics model (TADM) for estimating resistant areas, and a multistage model for estimating risk of herbicide resistance are discussed. An example is presented at the end to illustrate the two-step procedure

The spectral form factor is not self-averaging

The spectral form factor, k(t), is the Fourier transform of the two level correlation function C(x), which is the averaged probability for finding two energy levels spaced x mean level spacings apart. The average is over a piece of the spectrum of width W in the neighborhood of energy E0. An additional ensemble average is traditionally carried out, as in random matrix theory. Recently a theoretical calculation of k(t) for a single system, with an energy average only, found interesting nonuniversal semiclassical effects at times t approximately unity in units of {Planck's constant) /(mean level spacing). This is of great interest if k(t) is self-averaging, i.e, if the properties of a typical member of the ensemble are the same as the ensemble average properties. We here argue that this is not always the case, and that for many important systems an ensemble average is essential to see detailed properties of k(t). In other systems, notably the Riemann zeta function, it is likely possible to see the properties by an analysis of the spectrum.Comment: 4 pages, RevTex, no figures, submitted to Phys. Rev. Lett., permanent e-mail address, [email protected]

Orbital Magnetism of 2D Chaotic Lattices

We study the orbital magnetism of 2D lattices with chaotic motion of electrons withing a primitive cell. Using the temperature diagrammatic technique we evaluate the averaged value and rms fluctuation of magnetic response in the diffusive regime withing the model of non-interacting electrons. The fluctuations of magnetic susceptibility turn out to be large and at low temperature can be of the order of $\chi_{L} (k_{F}l)^{3/2}$, where $k_{F}$ is the Fermi wavevector, $l$ is the mean free path, and $\chi_{L}$ is the Landau susceptibility. In the certain region of magnetic fields the paramagnetic contribution to the averaged response is field independent and larger than the absolute value of Landau response.Comment: 6 pages, Latex file, figures available upon reques

Pengamatan Ekspresi Wajah Secara Adaptif Dengan Presentasi Pemutaran Musik

High life demands nowadays make the individual emotional state change easily. Music is one of many media that is used to stabilize a person's emotional condition. However, wrong use of music can worsen a person's emotional condition, as in the case of today's society.To prevent that, an application that can detect the user's facial expression to stabilize the user's emotional state through music is developed. The expression on the face is determined by the position of eyebrows, eyes, mouth, and wrinkles features. The positions of detected features are compared with those in a neutral face that has been previously calibrated. The difference of features' positions will be used as input of the trained neural network to determine the expression on the detected face.Through some experiments, the accuracy of detection of facial features and facial expressions are known. The detected expression will trigger the playback of music to stabilize the user's emotional condition. The weakness of this application is that the music library must be set manually by the user

MEMAHAMI AKSESIBILITAS SEBAGAI SALAH SATU FAKTOR PENENTU DALAM PEMILIHAN LOKASI TEMPAT TINGGAL DI KOTA CIMAHI

ABSTRAK Salah satu permasalahan yang kini sedang dihadapi oleh Kota Cimahi adalah laju pertumbuhan penduduk yang cukup tinggi. Peningkatan jumlah penduduk ini berikutnya akan berpengaruh terhadap pertambahan jumlah perumahan. Dalam memilih lokasi tempat tinggal banyak faktor yang mempengaruhi masyarakat, salah satunya adalah aksesibilitas menuju berbagai lokasi aktifitas.             Tujuan penelitian ini adalah untuk memahami aksesibilitas sebagai salah satu faktor penentu dalam pemilihan lokasi tempat tinggal di Kota Cimahi, dengan sasaran: (1) Mengidentifikasi tingkat kepentingan aksesibilitas dalam pemilihan tempat tinggal di Kota Cimahi. (2) Mengidentifikasi kesenjangan antara persepsi dan preferensi penghuni perumahan di Kota Cimahi tentang aksesibilitas menuju berbagai lokasi aktifitas. (3) Mengidentifikasi tingkat kepuasan aksesibilitas berdasarkan lokasi aktifitas di Kota Cimahi. (4) Mengidentifikasi pemilihan moda yang digunakan untuk beraktifitas dilihat dari tingkat kepuasan terhadap aksesibilitas dan lokasi aktifitas. Dari keempat sasaran tersebut, untuk sasaran (1), (3) dan (4) menggunakan analisis deskriptif kualitatif sedangkan untuk sasaran (2) menggunakan analisis GAP.             Hasil dari penelitian ini menunjukan bahwa (1) Diantara 10 faktor yang diuji untuk menilai tingkat kepentingan dalam pemilihan tempat tinggal aksesibilitas merupakan salah satu faktor utama. (2) Dari analisis kesenjangan ditemukan yang memiliki nilai positif hanya aksesibilitas menuju lokasi sarana pendidikan TK dan SD, sedangkan untuk aksesibilitas ke lokasi lainnya memiliki nilai negatif. (3) berdasarkan hasil analisis didapatkan 2 tingkat kepuasan terbanyak di Kota Cimahi berdasarkan lokasi aktifitas menurut responden yaitu tingkat kepuasan 0 dan -1. (4) Tingkat kepuasan terhadap aksesibilitas dan lokasi aktifitas tidak memiliki pengaruh terhadap pemilihan moda yang digunakan oleh masyarakat di Kota Cimahi.                                                                                                                                                         Kata Kunci: Pertumbuhan Penduduk, Pemilihan Lokasi Perumahan, Pertumbuhan Transportasi, Aksesibilitas. &nbsp

Maternal knowledge of effective breastfeeding and its benefits, as potential determinant of attitudes to infant feeding: A survey in Calabar, Nigeria

Appropriate breastfeeding is a cost-effective child survival strategy. This study assessed relationship between knowledge of breastfeeding and attitude towards infant feeding among pregnant women in Calabar, Nigeria. By convenience sampling, consenting antenatal clinic attendees were recruited from secondary health centers in Calabar. Pre-tested questionnaire was used to assess knowledge of different aspects of breastfeeding, while the Iowa Infant Feeding Attitude Scale (IIFAS) was used to assess attitude towards infant feeding. Data was analyzed using SPSS version 21.0, with p-value of less than 0.05 considered statistically significant. Two hundred and fifty (250) pregnant women were surveyed with mean age of 29.7 ± 6.1 years. One hundred and eight respondents (43.2%) had unsatisfactory levels of knowledge. Common areas of misconception were oral thrush effect of breastfeeding (47.2%), frequency of breast milk expression (47.6%), and effects of inverted nipples (45.6%). Most respondents (92.0%) had neutral attitude to infant feeding, and there was no significant relationship between overall knowledge of breastfeeding and infant feeding attitude (p>0.05). Of all the knowledge areas assessed, only benefits to mothers (r=0.11, p=0.08) and effective breastfeeding (r=0.17, p=0.01), had knowledge scores that correlated positively with infant feeding attitude scores. These findings contribute to existing literature required for improvement in policies and strategies, for breastfeeding education and child survival, especially in resource-poor settings. There is need for further research towards improving priority content of maternal health education during the time-constrained ANC visits. Keywords: Knowledge, breastfeeding, infant feeding attitude, pregnant women, Calabar, Nigeria   L'allaitement maternel approprié est une stratégie rentable de survie de l'enfant. Cette étude a évalué la relation entre la connaissance de l'allaitement maternel et l'attitude envers l'alimentation du nourrisson chez les femmes enceintes à Calabar, au Nigéria. Par échantillonnage de convenance, les participants consentants des cliniques prénatales ont été recrutés dans les centres de santé secondaires de Calabar. Un questionnaire pré-testé a été utilisé pour évaluer les connaissances sur les différents aspects de l'allaitement maternel, tandis que l'Iowa Infant Feeding Attitude Scale (IIFAS) a été utilisé pour évaluer l'attitude envers l'alimentation du nourrisson. Les données ont été analysées à l'aide de la version 21.0 de SPSS, avec une valeur p inférieure à 0,05 considérée comme statistiquement significative. Deux cent cinquante (250) femmes enceintes ont été interrogées avec un âge moyen de 29,7 ± 6,1 ans. Cent huit répondants (43,2%) avaient des niveaux de connaissances insatisfaisants. Les points communs d'idées fausses étaient l'effet du muguet buccal de l'allaitement (47,2%), la fréquence d'expression du lait maternel (47,6%) et les effets des mamelons inversés (45,6%). La plupart des répondants (92,0%) avaient une attitude neutre à l'égard de l'alimentation du nourrisson, et il n'y avait pas de relation significative entre la connaissance globale de l'allaitement et l'attitude en matière d'alimentation du nourrisson (p> 0,05). Parmi tous les domaines de connaissances évalués, seuls les avantages pour les mères (r = 0,11, p = 0,08) et l'allaitement maternel efficace (r = 0,17, p = 0,01) présentaient des scores de connaissance qui étaient en corrélation positive avec les scores d'attitude en matière d'alimentation du nourrisson. Ces résultats contribuent à la littérature existante nécessaire pour améliorer les politiques et stratégies, pour l'éducation à l'allaitement maternel et la survie de l'enfant, en particulier dans les milieux pauvres en ressources. Des recherches supplémentaires sont nécessaires pour améliorer le contenu prioritaire de l'éducation à la santé maternelle pendant les visites prénatales limitées dans le temps. Mots-clés: Connaissances, allaitement, attitude en matière d'alimentation du nourrisson, femmes enceintes, Calabar, Nigéri

Coulomb singularity effects in tunnelling spectroscopy of individual impurities

Non-equilibrium Coulomb effects in resonant tunnelling processes through deep impurity states are analyzed. It is shown that Coulomb vertex corrections to the tunnelling transfer amplitude lead to a power-law singularity in current- voltage characteristicsComment: 7 pages, 2 figure