Ripple modulated electronic structure of a 3D topological insulator

3D topological insulators, similar to the Dirac material graphene, host linearly dispersing states with unique properties and a strong potential for applications. A key, missing element in realizing some of the more exotic states in topological insulators is the ability to manipulate local electronic properties. Analogy with graphene suggests a possible avenue via a topographic route by the formation of superlattice structures such as a moir\'e patterns or ripples, which can induce controlled potential variations. However, while the charge and lattice degrees of freedom are intimately coupled in graphene, it is not clear a priori how a physical buckling or ripples might influence the electronic structure of topological insulators. Here we use Fourier transform scanning tunneling spectroscopy to determine the effects of a one-dimensional periodic buckling on the electronic properties of Bi2Te3. By tracking the spatial variations of the scattering vector of the interference patterns as well as features associated with bulk density of states, we show that the buckling creates a periodic potential modulation, which in turn modulates the surface and the bulk states. The strong correlation between the topographic ripples and electronic structure indicates that while doping alone is insufficient to create predetermined potential landscapes, creating ripples provides a path to controlling the potential seen by the Dirac electrons on a local scale. Such rippled features may be engineered by strain in thin films and may find use in future applications of topological insulators.Comment: Nature Communications (accepted

Emergent quantum confinement at topological insulator surfaces

Bismuth-chalchogenides are model examples of three-dimensional topological insulators. Their ideal bulk-truncated surface hosts a single spin-helical surface state, which is the simplest possible surface electronic structure allowed by their non-trivial $\mathbb{Z}_2$ topology. They are therefore widely regarded ideal templates to realize the predicted exotic phenomena and applications of this topological surface state. However, real surfaces of such compounds, even if kept in ultra-high vacuum, rapidly develop a much more complex electronic structure whose origin and properties have proved controversial. Here, we demonstrate that a conceptually simple model, implementing a semiconductor-like band bending in a parameter-free tight-binding supercell calculation, can quantitatively explain the entire measured hierarchy of electronic states. In combination with circular dichroism in angle-resolved photoemission (ARPES) experiments, we further uncover a rich three-dimensional spin texture of this surface electronic system, resulting from the non-trivial topology of the bulk band structure. Moreover, our study reveals how the full surface-bulk connectivity in topological insulators is modified by quantum confinement.Comment: 9 pages, including supplementary information, 4+4 figures. A high resolution version is available at http://www.st-andrews.ac.uk/~pdk6/pub_files/TI_quant_conf_high_res.pd

Rice marketing system, profitability and middlemen’s role in two districts of Bangladesh

The study attempts to identify the rice marketing channels, market actors and their marketing functions in Bogura and Gaibandha districts in Bangladesh. The paper also examines the rice marketing cost and margin and highlight major obstacles of market actors. Primary data were collected from 25 middlemen by using pretested semi-structured interview schedule in 2017. Rice millers, wholesalers and retailers were the major market’s actors in the study areas. Most of the rice millers buy paddy directly from the farmers by using their agent. After processing rice, rice millers sell rice to the wholesalers, and retailers. Rice millers marketing costs were higher in the Bogura district (Tk.569.8/40kg) than Gaibandha district (Tk.526.0/40kg). However, retailers’ marketing costs were higher in Gaibandha district (Tk.43.0/40kg) than Bogura district (Tk.39.1/40kg). Among all intermediaries, marketing margins was highest for rice millers which were Tk. 227.5/40kg. Middlemen have no sufficient capital for investment. Therefore, Government, Non Government Organizations and other institutional credit should be available to them at the reasonable interest rate

Rice marketing system, profitability and middlemen’s role in two districts of Bangladesh

The study attempts to identify the rice marketing channels, market actors and their marketing functions in Bogura and Gaibandha districts in Bangladesh. The paper also examines the rice marketing cost and margin and highlight major obstacles of market actors. Primary data were collected from 25 middlemen by using pretested semi-structured interview schedule in 2017. Rice millers, wholesalers and retailers were the major market’s actors in the study areas. Most of the rice millers buy paddy directly from the farmers by using their agent. After processing rice, rice millers sell rice to the wholesalers, and retailers. Rice millers marketing costs were higher in the Bogura district (Tk.569.8/40kg) than Gaibandha district (Tk.526.0/40kg). However, retailers’ marketing costs were higher in Gaibandha district (Tk.43.0/40kg) than Bogura district (Tk.39.1/40kg). Among all intermediaries, marketing margins was highest for rice millers which were Tk. 227.5/40kg. Middlemen have no sufficient capital for investment. Therefore, Government, Non Government Organizations and other institutional credit should be available to them at the reasonable interest rate

Entomological Surveillance of Behavioural Resilience and Resistance in Residual Malaria Vector Populations.

The most potent malaria vectors rely heavily upon human blood so they are vulnerable to attack with insecticide-treated nets (ITNs) and indoor residual spraying (IRS) within houses. Mosquito taxa that can avoid feeding or resting indoors, or by obtaining blood from animals, mediate a growing proportion of the dwindling transmission that persists as ITNs and IRS are scaled up. Increasing frequency of behavioural evasion traits within persisting residual vector systems usually reflect the successful suppression of the most potent and vulnerable vector taxa by IRS or ITNs, rather than their failure. Many of the commonly observed changes in mosquito behavioural patterns following intervention scale-up may well be explained by modified taxonomic composition and expression of phenotypically plastic behavioural preferences, rather than altered innate preferences of individuals or populations. Detailed review of the contemporary evidence base does not yet provide any clear-cut example of true behavioural resistance and is, therefore, consistent with the hypothesis presented. Caution should be exercised before over-interpreting most existing reports of increased frequency of behavioural traits which enable mosquitoes to evade fatal contact with insecticides: this may simply be the result of suppressing the most behaviourally vulnerable of the vector taxa that constituted the original transmission system. Mosquito taxa which have always exhibited such evasive traits may be more accurately described as behaviourally resilient, rather than resistant. Ongoing national or regional entomological monitoring surveys of physiological susceptibility to insecticides should be supplemented with biologically and epidemiologically meaningfully estimates of malaria vector population dynamics and the behavioural phenotypes that determine intervention impact, in order to design, select, evaluate and optimize the implementation of vector control measures

Value Co-creation by Compulsory Facebook-Community in Corporate Culture: A Case Study Malaysian Logistic Company

The main purpose of this study was to investigate the value co-creation process using Facebook as compulsory by a company. A new value co-creation model was developed showing how Facebook could be successfully executed as a platform for the value co-creation process with the aim of providing the best possible service to the recipients. This research employed an explanatory case study due to its uniqueness, especially for sufficient and in-depth comprehension of the phenomenon. PKT Logistics Group Sdn Bhd (PKT) was chosen for this study due to its exceptional characteristic of declaring itself as ‘Facebook compulsory’ company in business after Facebook. Data were obtained from interviews, direct observations, and a questionnaire survey of the company’s top management, selected employees, and customers.The proposed model has successfully connected the company’s leader, employees, and customers with each other for attaining the ‘Ba’ in new knowledge creation spirally using Facebook as an effective platform. This has resulted in the achievement of a service-oriented value co-creation process.This research has contributed to create a new model of the value co-creation process involving all the stakeholders via a ‘Facebook community’, which could be useful for other service providers.This study differentiates itself from the restricted application of Facebook in business by focusing on Facebook as compulsory in a corporate culture. The new value co-creation process model thru a ‘Facebook community’ is original and might be first of this type study

Improving Industry- University R and D Partnership Project Management: A Pilot Study

In April 2004, a new law turned Japanese national universities into independent public corporations. This change has increased pressure on them to look to industry for more support than ever before. Since one of the laboratories in Japan Advanced Institute of Science and Technology’s (JAIST’s) School of Materials Science is involved in a collaborative project with two industrial partners (one large and one small), we saw an excellent opportunity to conduct a pilot study on an industry-university knowledge partnership for a scientific research and development project in the Japanese national university setting. The purpose of our study is to identify both which areas and considerations have the most influence on such projects and how such projects can be improved. This paper presents our methodology and data results. Most importantly, it presents a list of specific suggestions for improving project performance. Although it was a pilot study with a small number of respondents, this study still may have significance in terms of the suggestions for improving collaborative projects and in regard to the data-gathering methodology we used. We planned to provide results of the study to the project team members and recommend they apply the most important suggestions for improving their project. We also planned to do a follow-up study to determine whether or not the project is improved by the implementation of these key suggestions

Sindroma Lesch Nyhan

Pendahuluan:Sindroma Lesch-Nyhan ( LSN) adalah  kumpulan  gangguan metabolisme disebabkan oleh kekurangan enzim HPRT (hypoxanthineguaninephosphoribosyltransferase) yang menyebabkan  produksi asam urat berlebihan. Penyakit ini diturunkan secara genetik yang mewarisi x-linked resesive .Dalam keadaan normal enzim hprt ditemukan dalam tiap sel di tubuh di mana persentase tertinggi ditemukan dalam otak terutama di ganglia basalis. Prognosis LSN  buruk , kematian terjadi biasanya disebabkan oleh kegagalan ginjal atau pneumonia aspirasi . kematian terjadi  pada tahun pertama atau kedua kehidupan bila tidak diterapi. Pengobatan dengan  alopurinol dapat membantu menjaga fungsi ginjal dan memberikan harapan hidup lebih lama. Tujuan ini dari literatur ini adalah memberi informasi mengenai LSN sebagai sebuah kelainan genetik yang jarang ditemui namun mudah untuk dicurigai karena gambaran klinisnya yang khas. Literatur ini menjelaskan Informasi tentang sejarah, definisi, pathogenesis, diagnosis, dan upaya pencegahan maupun penatalaksanaannya. Diskusi:Purin merupakan salah satu senyawa organik heterosiklik yang terdiri dari sebuah cincin imidazol dan pirimidina . Mutasi gen HPRT  terjadi dalam bentuk spanning  atau twisting, delesi, duplikasi dan mutasi ganda. Ada tiga mekanisme dasar dari patogenesis LSN, yaitu: genetika molekuler, biokimia, neuropatogenesis. Simpulan: Kekurangan enzim HPRTmenyebabkan hipoxantin dan guanina tidak didaur ulang menjadi asam urat.Kekurangan enzim HPRT disebabkan mutasi gen. Upaya terkini dan  lebih lanjut harus ditekankan dalam pencegahan dan pengobatan dari gangguan perilaku yang disebabkan oleh kelainan neurologi pada LSN. Farmakologi genetik dan terapi pembedahan dapat menjadi pilihan utama