Microlensing of Extended Stellar Sources

We investigate the feasibility of reconstructing the radial intensity profile of extended stellar sources by inverting their microlensed light curves. Using a simple, linear, limb darkening law as an illustration, we show that the intensity profile can be accurately determined, at least over the outer part of the stellar disc, with realistic light curve sampling and photometric errors. The principal requirement is that the impact parameter of the lens be less than or equal to the stellar radius. Thus, the analysis of microlensing events provides a powerful method for testing stellar atmosphere models.Comment: 4 pages LaTeX, to appear in New Astronomy Reviews - proceedings of the Oxford Workshop `Gravitational Lensing: Nature's Own Weighing Scales'. Uses elsart.cls. Paper also available at ftp://info.astro.gla.ac.uk/pub/martin/extended.p

Non-invasive, near-field terahertz imaging of hidden objects using a single pixel detector

Terahertz (THz) imaging has the ability to see through otherwise opaque materials. However, due to the long wavelengths of THz radiation ({\lambda}=300{\mu}m at 1THz), far-field THz imaging techniques are heavily outperformed by optical imaging in regards to the obtained resolution. In this work we demonstrate near-field THz imaging with a single-pixel detector. We project a time-varying optical mask onto a silicon wafer which is used to spatially modulate a pulse of THz radiation. The far-field transmission corresponding to each mask is recorded by a single element detector and this data is used to reconstruct the image of an object placed on the far side of the silicon wafer. We demonstrate a proof of principal application where we image a printed circuit board on the underside of a 115{\mu}m thick silicon wafer with ~100{\mu}m ({\lambda}/4) resolution. With subwavelength resolution and the inherent sensitivity to local conductivity provided by the THz probe frequencies, we show that it is possible to detect fissures in the circuitry wiring of a few microns in size. Imaging systems of this type could have other uses where non-invasive measurement or imaging of concealed structures with high resolution is necessary, such as in semiconductor manufacturing or in bio-imaging

Extending the Current Theorization On Cyberbullying: Importance of Including Socio-Psychological Perspectives

Despite an abundance of research from multiple perspectives and disciplines, to date cyberbullying research has been fragmented and is often conducted atheoretically, using theories borrowed from general psychology and/or criminology, or considers only individual-level explanations such as demographics, personalities, and psychological conditions which may be insufficient to fully understand and explain the behaviour. Social psychological approaches that examine the everyday power relations in children\u2019s lives and the study of identity, relationships, and belonging systems may provide meaningful context and a more holistic perspective. The purpose of this paper is to demonstrate the positive impact of applying identity theories and a sociological perspective to the study of cyberbullying. This paper provides an overview of cyberbullying, followed by examples of how general psychological theories and theories borrowed from criminology and aggression have been applied to cyberbullying, including a cyberbullying-specific theory. Several key theories of identity that could be employed in the study of cyberbullying are then identified. Lastly, the utility of using a socio-psychological perspective using social identity theory and social network analysis to study of cyberbullying is explored. In order to manage cyber violence, we need to act on multiple levels, including individual, relational, organizational, and community levels

Sistem Pendukung Keputusan Penempatan Jabatan Menggunakan Metode Simple Additive Weighting (Saw) Berbasis Web (Studi Kasus : Smk PGRI Pekanbaru)

Dalam lingkungan Perusahaan atau organisasi, komputer merupakan alat bantu yang mutlak diperlukan sehingga penerapan sebuah sistem berbasis komputer menjadi kebutuhan pokok dan memberikan keunggulan kompetitif. Masalah yang terjadi dalam proses evaluasi (penilaian) kinerja guru diantaranya adalah terutama jika beberapa guru yang ada memiliki kemampuan yang tidak jauh berbeda. Proses evaluasi (penilaian) yang rumit terjadi sekarang umumnya adalah adanya guru yang menempati jabatan yang hanya melihat pada kriteria pertama saja, tetapi guru tersebut belum tentu unggul pada beberapa kriteria-kriteria yang lain. SMK PGRI pekanbaru merupakan salah satu sekolah swasta yang ada di pekanbaru. Dimana selama ini pada proses penempatan jabatan hanya dilihat dari hasil tes dan beberapa persyaratan dasar lainya. Sebagian besar guru mengalami kesulitan beradaptasi dengan tugas-tugas yang harus dilaksanakan karena tidak memiliki latar belakang pengetahuan yang sesuai dengan posisi yang yang ditempatinya. Jika dibiarkan terus-menerus, hal ini akan berdampak negatif pada kinerja yang diberikan dan menghambat kemajuan sekolah. Oleh karena itu, Pihak sekolah mencari solusi agar dapat meminimalisasi kesalahan yang diakibatkan oleh kinerja guru, yaitu dengan cara menempatkan guru pada posisi atau bidang yang sesuai dengan kemampuanya

High-Resolution Vertical Habitat Mapping of a Deep-Sea Cliff offshore Greenland

Recent advances in deep-sea exploration with underwater vehicles have led to the discovery of vertical environments inhabited by a diverse sessile fauna. However, despite their ecological importance, vertical habitats remain poorly characterized by conventional downward-looking survey techniques. Here we present a high-resolution 3-dimensional habitat map of a vertical cliff hosting a suspension-feeding community at the flank of an underwater glacial trough in the Greenland waters of the Labrador Sea. Using a forward-looking set-up on a Remotely Operated Vehicle (ROV), a high-resolution multibeam echosounder was used to map out the topography of the deep-sea terrain, including, for the first time, the backscatter intensity. Navigational accuracy was improved through a combination of the USBL and the DVL navigation of the ROV. Multi-scale terrain descriptors were derived and assigned to the 3D point cloud of the terrain. Following an unsupervised habitat mapping approach, the application of a K-means clustering revealed four potential habitat types, driven by geomorphology, backscatter and fine-scale features. Using groundtruthing seabed images, the ecological significance of the four habitat clusters was assessed in order to evaluate the benefit of unsupervised habitat mapping for further fine-scale ecological studies of vertical environments. This study demonstrates the importance of a priori knowledge of the terrain around habitats that are rarely explored for ecological investigations. It also emphasizes the importance of remote characterization of habitat distribution for assessing the representativeness of benthic faunal studies often constrained by time-limited sampling activities. This case study further identifies current limitations (e.g., navigation accuracy, irregular terrain acquisition difficulties) that can potentially limit the use of deep-sea terrain models for fine-scale investigations

Influence of nanotube length and density on the plasmonic terahertz response of single-walled carbon nanotubes

We measure the conductivity spectra of thin films comprising bundled single-walled carbon nanotubes (CNTs) of different average lengths in the frequency range 0.3-1000 THz and temperature interval 10-530 K. The observed temperature-induced changes in the terahertz conductivity spectra are shown to depend strongly on the average CNT length, with a conductivity around 1 THz that increases/decreases as the temperature increases for short/long tubes. This behaviour originates from the temperature dependence of the electron scattering rate, which we obtain from Drude fits of the measured conductivity in the range 0.3-2 THz for 10 $\mu$m length CNTs. This increasing scattering rate with temperature results in a subsequent broadening of the observed THz conductivity peak at higher temperatures and a shift to lower frequencies for increasing CNT length. Finally, we show that the change in conductivity with temperature depends not only on tube length, but also varies with tube density. We record the effective conductivities of composite films comprising mixtures of WS$_2$ nanotubes and CNTs vs CNT density for frequencies in the range 0.3-1 THz, finding that the conductivity increases/decreases for low/high density films as the temperature increases. This effect arises due to the density dependence of the effective length of conducting pathways in the composite films, which again leads to a shift and temperature dependent broadening of the THz conductivity peak.Comment: Submitted to Journal of Physics D. Main manuscript: 9 pages, 8 figures. Supplementary material: 5 pages, 6 figure

Formation of Topological Defects with Explicit Symmetry Breaking

We demonstrate a novel mechanism for the formation of topological defects in a first order phase transition for theories in the presence of small explicit symmetry breaking terms. We carry out numerical simulations of collisions of two bubbles in 2+1 dimensions for a field theory where U(1) global symmetry is spontaneously as well as explicitly broken. In the coalesced region of bubble walls, field oscillations result in the decay of the coalesced portion in a large number of defects (e.g. ten vortices and anti-vortices). We discuss the implications of our results for axionic strings in the early Universe, for baryon formation in quark-gluon plasma, and for electric or magnetic field.Comment: Latex file, 8 pages, 6 uuencoded postscript figure

Phenotypic characteristics of Exotic-broiler, Kampung, Male Exotic-layer, KUB-1 and Pelung chickens

The needs for chicken meat have been dominated by meat from exotic broilers (bred from imported parent). The potential of local broilers chicken in Indonesia is expected to be able to provide the meat for national needs for chicken meat. The objective of this research was to determine the day-old-chick (DOC) phenotypic characteristics of chickens in Indonesia that have the potential as broilers. The phenotypic characteristics are in the form of body morphometry, visceral organ weight and small intestinal histo-morphology. The chickens used were the DOC type of exotic Broiler, Kampung, exotic male Layer, KUB-1 and Pelung. A total of 125 chickens consisting of 25 chickens of each strain at posthatched age were observed for its body morphometry and its visceral organ weight, and small intestinal histo-morphology. The observed data were then analyzed by similarity analysis using MVSP 3.22 to create a dendogram with the Unweighted Pair Group with Aritmetic Average (UPGMA) method. Results showed that there were 2 different clusters from the level of similarity in their characteristics. Exotic broilers had 94.65% similarity to male exotic layer chicken and 92.26% to pelung chicken, while Kampung chickens had 90.16% similarity to KUB-1Chicken. In conclusion, it is indicated that the level of similarity of the phenotypic characteristics of pelung chickens were close to the type of exotic broiler and male exotic layer chicken. This level of similarity lead  to the expectation that pelung chickens potential to be a candidate for meat-type of local chicken

Reaching expert consensus on training different cadres in delivering early childhood development: technical report

The Sustainable Development Goals (SDGs) signal a greater focus on inter-sectoral, collaborative approaches to ensuring that all human beings can fulfil their potential in dignity and equality. This is reflected in the current global concern with promotion of holistic, community-based programmes to support early childhood development and wellbeing ? widely referred to as ?early childhood development? (ECD). Within this context, the study reported here sought to achieve consensus among 14 global experts on training needs for three groups of personnel (?cadres?) involved in delivery of early childhood development (ECD) programmes. The three cadre groups, identified via a comprehensive review of literature on current issues in the provision of ECD, comprise delivery of education, health and community-based early childhood interventions across a diverse range of low resource settings. The study responds to a gap in knowledge on training needs for ECD cadres, associated with a serious dearth of human resources to support provision of ECD services. Key challenges reported here, based on comprehensive review of available literature, include: 1. A long-running, severe global shortage in availability of cadres to support delivery of ECD programmes. 2. To date, delivery of key health and education interventions principally in siloes, with limited integration and practitioners/professionals/para-professionals widely employed in vertical programmes. 3. Low professional and social status of many ECD cadres, due to a lack of systematic recognition and support. This has resulted in large numbers of cadres with undefined career paths, and high rates of turnover / attrition2. In response, expert consensus points to the following potential strategies for enhancing provision of ECD cadres training and professional development: 1. Development of coherent systems to support ECD training and professional development. a. Findings indicate consensus around commonalities among and distinctions between essential skills and knowledge required for education professionals, health professionals and non-certified para-professional groups. These insights could provide a basis for establishing coherent, joined-up professional pathways and support systems for development of ECD cadres. b. Consensus around the respective roles of these three cadres is reflected in the distinct training needs outlined for each group. There is consensus that, while noncertified para-professionals require programme-specific training to facilitate delivery of particular tasks, certified education and health professionals require training in more advanced skills such as problem-solving and flexibility. Exposure to a range of different programmes and approaches is required for certified professionals, to facilitate informed decision making around programme development and adapting / responding to local contextual needs. These distinctions could provide a basis for establishing clarity in respective roles for ECD cadres with regard to programme delivery. c. Consensus around training needs across cadre groups is indicated, in particular the need for on-going mentoring and supervision. While there is acknowledgment among experts about complexities associated with provision of on-going support, consensus around this component of training was strongest among all aspects surveyed. This reflects widespread concern among participating experts, as well as within the literature, that short-term training for ECD cadres must be followed up with opportunities for continuing professional development and systematic support, to facilitate sustained effective practice. 2. Within systems for ECD cadres training, a strong focus on the importance of contextually grounded programmes, materials / resources and strategies for implementation. a. There is strong consensus that ECD cadres training should be contextually-grounded to ensure responsive, effective provision. Training should be based on and promote careful consideration of a range of factors that shape provision of ECD, including but not restricted to, policy, budgets, available resources, local values, beliefs and practices. 3. Adoption of the concept of nurturing care as an underpinning principle for provision of ECD cadres training. a. Delphi findings indicate consensus around essential dispositions, or attitudes, required to support caring, respectful, responsive and trustful interactions with children, caregivers and communities. They also indicate that all cadres require knowledge and skills in promoting early stimulation; child-centred learning and development; effective communication and collaboration; problem solving, and reflective practice. These strategies are outlined in the proposed framework provided below, which identifies unique roles / training needs for different cadre groups, as well as opportunities for enhancing integration across ECD cadres training systems. 3 Experts suggest that these ?dispositions?, which are essential for effective provision, should be viewed as malleable. Training should work / be designed to promote, model and strengthen these characteristics

Density of kinks just after a quench in an overdamped system

A quench in an overdamped one dimensional $\phi^4$ model is studied by analytical and numerical methods. For an infinite system or a finite system with free boundary conditions, the density of kinks after the transition is proportional to the eighth root of the rate of the quench. For a system with periodic boundary conditions, it is proportional to the fourth root of the rate. The critical exponent predicted in Zurek scenario is put in question.Comment: 4 pages in RevTex + 1 .ps fil