Plasmon induced transparency in graphene based terahertz metamaterials

Plasmon induced transparency (PIT) effect in a terahertz graphene metamaterial is numerically and theoretically analyzed. The proposed metamaterial comprises of a pair of graphene split ring resonators placed alternately on both sides of a graphene strip of nanometer scale. The PIT effect in the graphene metamaterial is studied for different vertical and horizontal configurations. Our results reveal that there is no PIT effect in the graphene metamaterial when the centers of both the split ring resonators and the graphene strip are collinear to each other. This is a noteworthy feature, as the PIT effect does not vanish for similar configuration in a metal-based metamaterial structure. We have further shown that the PIT effect can be tuned by varying the Fermi energy of graphene layer. A theoretical model using the three level plasmonic system is established in order to validate the numerical results. Our studies could be significant in designing graphene based frequency agile ultra-thin devices for terahertz applications

Are 11 Weeks Weak? A Conversation With Instructors

Undergraduate programs in the United States range from locally funded, two-year community colleges, to state and federally funded universities, as well as private, tuition-based institutions. Assumingly most programs attempt to facilitate a relevant and balanced curriculum that prepares students for the general and perhaps specific obstacles that they will experience in a professional environment. Successful curricula may also attempt to prepare students for the social, cultural and economic challenges that they will experience in their personal life. The question of how various programs implement this fundamental yet daunting task has been in the past and assuredly will remain a part of academia, research studies and discussions. In general, these debates relate to the breadth of a program. However, within this arena, the pertinent factor is a program’s length—the number of credit hours congruent to or with the duration of a quarter or a semester that are required to achieve a particular degree. This aspect may be of significance to prospective students, their parents, spouses and other individuals who potentially hold a role in the selection of the student’s educational process and future. Undeniable factors in the decision-process include admission’s work, the program itself, the degree offering, the reputation of the institution, cost of credit hours, the school’s physical location and its supporting environment—including housing accommodation, libraries, activity centers, proximity to family and workplace. Regardless of the various options, some individuals make the decision to enroll in an 11-week quarter-based educational model. The Art Institutes utilize this educational model at their thirty-five locations across the United States and two facilities in Canada. This system leads us to the question: do eleven weeks provide sufficient time for a student to interpret, analyze and demonstrate the course objectives? With an effort to advocate open-minded and non-conformist responses questions relating to this topic were asked in an informal setting—to new and experienced instructors who currently teach full or part-time at The Art Institute of Dallas. All possess a Masters or terminal degree in their fields of instruction and have been teaching in higher education for five or more years. Data from these conversations was gathered and has become the essence of this paper. Readers may assume current faculty advocate this model in order to maintain active employment. However, those assumptions are erroneous. The relevance of this research is important to prospective students, parents and all the individuals involved in higher education across the continuum of five- to seventeen-week terms. Those individuals can ‘hear’ the pros and cons (if any) of such a model from instructors themselves. This inquiry contributes to the conversations and value as found and defined by instructors. Via their research, the authors hope to facilitate a dialogue that advocates/or does not advocate the institution of an 11-week educational model amongst all the interested individuals in higher education. A deeper level of understanding and respect for instructors who successfully teach in quarter-based educational models can be obtained. Administrators may find value in this research for economic and accounting reasons. Both the authors clearly understand that the ‘instructor’ is only one component of any successful educational model. Opinions from others such as the students and alumni are also of immense value. These individuals will be addressed in their further studies

Gap junctions and connexin hemichannels in the regulation of haemostasis and thrombosis

Platelets are involved in the maintenance of haemostasis but their inappropriate activation leads to thrombosis, a principal trigger for heart attack and ischemic stroke. Although platelets circulate in isolation, upon activation they accumulate or aggregate together to form a thrombus, where they function in a coordinated manner to prevent loss of blood and control wound repair. Recent reports indicate that the stability and functions of a thrombus are maintained through sustained, contact dependent signalling between platelets. Given the role of gap junctions in the coordination of tissue responses, it was hypothesized that gap junctions may be present within a thrombus and mediate intercellular communication between platelets. Therefore studies were performed to explore the presence and functions of connexins in platelets. In this brief review, the roles of hemichannels and gap junctions in the control of thrombosis and haemostasis and the future directions for this research will be discussed

Legal Implications for NMPs

Review of legal and professional responsibilities for non medical prescribers along with case examples

Pemberdayaan Perempuan melalui Daya Saing Produk Berbahan Ramah Lingkungan (Go Green) di USAha Pembuatan Tikar Daun Purun Palembang

Kota Palembang, sebagai ibu kota provinsi Sumatera Selatan terkenal sebagai pusat kuliner dan industri kerajinankhas Palembang. Industri tikar berbahan dasar daun purun merupakan USAha turun temurun dan menjadi USAha yangbanyak dilakukan oleh kaum perempuan terutama ibu-ibu yang memiliki kemampuan menganyam daun purunmenjadi produk tikar daun purun. Pemerintah Daerah berupaya untuk mempertahankan dan melestarikan USAha ini,melalui pemberian akses di bidang permodalan, pelatihan, pemasaran, mengikutsertakan pameran kerajinannusantara di Jakarta. Namun, USAha ini masih belum maksimal karena programm yang diberikan masih berjangkapendek, belum menyentuh akar sebenarnya yaitu masalah kemiskinan. Usaha ini juga, belum diorganisir denganbaik, dan belum dikelola secara profesional, padahal dari USAha ini secara tidak langsung sudah banyak memberikanmanfaat bagi pendapatan keluarga. Rumusan masalah adalah bagaimana memberdayakan kaum perempuan melaluipotensi-potensi yang dimilikinya, sehingga mampu membantu meningkatkan pendapatan keluarga. Penelitian inijuga untuk mengetahui kendala-kendala yang terjadi pada USAha pembuatan tikar daun purun ini, serta solusi yangdiperlukan dari temuan penelitian ini. Tujuan penelitian ini adalah untuk menggali potensi yang dimiliki kaumperempuan pengrajin, dan sekaligus pelaku USAha, menggali dan menggambarkan kendala-kendala kaum perempuandalam memanfaatkan bahan baku daun purun yang ramah lingkungan, serta solusi yang ditawarkan dari temuan ini.Metode yang digunakan adalah dengan metode forum diskusi kelompok dan wawancara. Hasil yang ditemukandalam penelitian ini antara lain; 1). Sebagian besar USAha tikar daun purun dilakukan oleh kaum perempuan, danmerupakan USAha turun temurun. Usaha ini mampu membantu pendapatan keluarga. 2). Kendala yang dihadapiadalah bahan baku daun purun yang jumlahnya semakin menurun karena adanya Perubahan fungsi lahan menjadiperkebunan sawit, dan musibah kebakaran yang kerap muncul setiap musim kemarau tiba, dan 3). Perlu adanyapembinaan yang optimal dari pihak pemerintah daerah, dan lembaga terkait dalam hal keuangan, pemasaran,pelatihan produk yang lebih variatif dan kompetitif serta menjadikan lokasi sekarang ini menjadi daerah sentra barupembuatan tikar daun purun yang berada di dalam kota Palembang

Detecting human impacts on the flora, fauna, and summer monsoon of Pleistocene Australia

International audienceAll of Australia's largest mammalian vertebrates became extinct 50 to 45 ka (thousand years ago), shortly after human colonization. Between 60 and 40 ka Australian climate was similar to present and not changing rapidly. Consequently, attention has turned toward plausible human mechanisms for the extinction, with proponents for over-hunting, ecosystem change, and introduced disease. To differentiate between these options we utilize isotopic tracers of diet preserved in eggshells of two large, flightless birds to track the status of ecosystems before and after human colonization. ?13C preserved in their eggshells monitor a bird's dietary intake in the weeks to months before egg-laying. More than 500 dated eggshells from central Australia of the Australian emu (Dromaius novaehollandiae), an opportunistic, dominantly herbivorous feeder, provide a continuous 140 kyr dietary ? 13C reconstruction. More than 350 dated eggshells from the same region of the heavier, extinct, giant bird Genyornis newtoni define its dietary intake from 140 ka until its extinction about 50 ka. Additional dietary records for both species were developed from two distant regions. Dromaius eggshell dietary ?13C reveals an unprecedented reduction in the bird's food resources about 50 ka, coeval in all three regions, suggesting conversion at that time of a tree/shrub savannah with occasionally rich grasslands to the modern desert scrub. We speculate that ecosystem collapse across the arid and semi-arid zones is a consequence of systematic burning by early humans. Genyornis diet everywhere is more restricted than in co-existing Dromaius, implying a more specialized feeding strategy. These data suggest that generalist feeders, such as Dromaius, were able to adapt to a changed vegetation regime, whereas more specialized feeders, such as Genyornis, became extinct. The altered vegetation may have also impacted Australian climate. Changes in the strength of climate feedbacks linked to vegetation and soil type (moisture recycling, surface roughness, albedo) may have weakened the penetration of monsoon moisture into the continental interior under the new ecosystem. Climate modeling suggests such a shift may have reduced monsoon rain in the interior by as much as 50%

A dedicated greedy pursuit algorithm for sparse spectral representation of music sound

A dedicated algorithm for sparse spectral representation of music sound is presented. The goal is to enable the representation of a piece of music signal as a linear superposition of as few spectral components as possible, without affecting the quality of the reproduction. A representation of this nature is said to be sparse. In the present context sparsity is accomplished by greedy selection of the spectral components, from an overcomplete set called a dictionary. The proposed algorithm is tailored to be applied with trigonometric dictionaries. Its distinctive feature being that it avoids the need for the actual construction of the whole dictionary, by implementing the required operations via the fast Fourier transform. The achieved sparsity is theoretically equivalent to that rendered by the orthogonal matching pursuit (OMP) method. The contribution of the proposed dedicated implementation is to extend the applicability of the standard OMP algorithm, by reducing its storage and computational demands. The suitability of the approach for producing sparse spectral representation is illustrated by comparison with the traditional method, in the line of the short time Fourier transform, involving only the corresponding orthonormal trigonometric basis

Inter-hemispheric linkages in climate change: Paleo-perspectives for future climate change

The Pole-Equator-Pole (PEP) projects of the PANASH (Paleoclimates of the Northern and Southern Hemisphere) programme have significantly advanced our understanding of past climate change on a global basis and helped to integrate paleo-science across regions and research disciplines. PANASH science allows us to constrain predictions for future climate change and to contribute to the management of consequent environmental changes. We identify three broad areas where PEP science makes key contributions. 1. The pattern of global changes. Knowing the exact timing of glacial advances (synchronous or otherwise) during the last glaciation is critical to understanding interhemispheric links in climate. Work in PEPI demonstrated that the tropical Andes in South America were deglaciated earlier than the Northern Hemisphere (NH) and that an extended warming began there ca. 21 000 cal years BP. The general pattern is consistent with Antarctica and has now been replicated from studies in Southern Hemisphere (SH) regions of the PEPII transect. That significant deglaciation of SH alpine systems and Antarctica led deglaciation of NH ice sheets may reflect either i) faster response times in alpine systems and Antarctica, ii) regional moisture patterns that influenced glacier mass balance, or iii) a SH temperature forcing that led changes in the NH. This highlights the limitations of current understanding and the need for further fundamental paleoclimate research. 2. Changes in modes of operation of oscillatory climate systems. Work across all the PEP transects has led to the recognition that the El Nino Southern Oscillation (ENSO) phenomenon has changed markedly through time. It now appears that ENSO operated during the last glacial termination and during the early Holocene, but that precipitation teleconnections even within the Pacific Basin were turned down, or off. In the modern ENSO phenomenon both inter-annual and seven year periodicities are present, with the inter-annual signal dominant. Paleo-data demonstrate that the relative importance of the two periodicities changes through time, with longer periodicities dominant in the early Holocene. 3. The recognition of climate modulation of oscillatory systems by climate events. We examine the relationship of ENSO to a SH climate event, the Antarctic cold reversal (ACR), in the New Zealand region. We demonstrate that the onset of the ACR was associated with the apparent switching on of an ENSO signal in New Zealand. We infer that this related to enhanced zonal SW winds with the amplification of the pressure fields allowing an existing but weak ENSO signal to manifest itself. Teleconnections of this nature would be difficult to predict for future abrupt change as boundary conditions cannot readily be specified. Paleo-data are critical to predicting the teleconnections of future changes

A DNA nanomachine that maps spatial and temporal pH changes inside living cells

DNA nanomachines are synthetic assemblies that switch between defined molecular conformations upon stimulation by external triggers. Previously, the performance of DNA devices has been limited to in vitro applications. Here we report the construction of a DNA nanomachine called the I-switch, which is triggered by protons and functions as a pH sensor based on fluorescence resonance energy transfer (FRET) inside living cells. It is an efficient reporter of pH from pH 5.5 to 6.8, with a high dynamic range between pH 5.8 and 7. To demonstrate its ability to function inside living cells we use the I-switch to map spatial and temporal pH changes associated with endosome maturation. The performance of our DNA nanodevices inside living systems illustrates the potential of DNA scaffolds responsive to more complex triggers in sensing, diagnostics and targeted therapies in living systems