127 research outputs found

    Near-unity light-matter interaction in mid-infrared van der Waals nanocavities

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    Accessing mid-infrared radiation is of great importance for a range of applications, including thermal imaging, sensing, and radiative cooling. Here, we study light interaction with hexagonal boron nitride nanocavities and reveal strong and tunable resonances across its hyperbolic transition. In addition to conventional phonon-polariton excitations, we demonstrate that the high refractive index of hexagonal boron nitride outside the Reststrahlen band allows enhanced light-matter interactions in deep subwavelength (<{\lambda}/15) nanostructures across a broad 7-8 {\mu}m range. Near-unity absorption and high quality (Q>80) resonance interaction in the vicinity of the transverse optical phonon is observed. Our study provides new avenues to design highly efficient and ultracompact structures for controlling mid-infrared radiation and accessing strong light-matter interaction.Comment: 14 pages, 4 figure

    Dynamical Belyi maps

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    We study the dynamical properties of a large class of rational maps with exactly three ramification points. By constructing families of such maps, we obtain infinitely many conservative maps of degree dd; this answers a question of Silverman. Rather precise results on the reduction of these maps yield strong information on the rational dynamics.Comment: 21 page

    Medication-overuse headache : a widely recognized entity amidst ongoing debate

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    Medication overuse in primary headache disorders is a worldwide phenomenon and has a role in the chronification of headache disorders. The burden of disease on individuals and societies is significant due to high costs and comorbidities. In the Third Edition of the International Classification of Headache Disorders, medication-overuse headache is recognized as a separate secondary entity next to mostly primary headache disorders, although many clinicians see the disease as a sole complication of primary headache disorders. In this review, we explore the historical background of medication-overuse headache, its epidemiology, phenomenology, pathophysiology and treatment options. The review explores relevant unanswered questions and summarizes the current debates in medication-overuse headache

    Using Remotely-Sensed Estimates of Soil Moisture to Infer Soil Texture and Hydraulic Properties across a Semi-arid Watershed

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    Near-surface soil moisture is a critical component of land surface energy and water balance studies encompassing a wide range of disciplines. However, the processes of infiltration, runoff, and evapotranspiration in the vadose zone of the soil are not easy to quantify or predict because of the difficulty in accurately representing soil texture and hydraulic properties in land surface models. This study approaches the problem of parameterizing soils from a unique perspective based on components originally developed for operational estimation of soil moisture for mobility assessments. Estimates of near-surface soil moisture derived from passive (L-band) microwave remote sensing were acquired on six dates during the Monsoon '90 experiment in southeastern Arizona, and used to calibrate hydraulic properties in an offline land surface model and infer information on the soil conditions of the region. Specifically, a robust parameter estimation tool (PEST) was used to calibrate the Noah land surface model and run at very high spatial resolution across the Walnut Gulch Experimental Watershed. Errors in simulated versus observed soil moisture were minimized by adjusting the soil texture, which in turn controls the hydraulic properties through the use of pedotransfer functions. By estimating a continuous range of widely applicable soil properties such as sand, silt, and clay percentages rather than applying rigid soil texture classes, lookup tables, or large parameter sets as in previous studies, the physical accuracy and consistency of the resulting soils could then be assessed. In addition, the sensitivity of this calibration method to the number and timing of microwave retrievals is determined in relation to the temporal patterns in precipitation and soil drying. The resultant soil properties were applied to an extended time period demonstrating the improvement in simulated soil moisture over that using default or county-level soil parameters. The methodology is also applied to an independent case at Walnut Gulch using a new soil moisture product from active (C-band) radar imagery with much lower spatial and temporal resolution. Overall, results demonstrate the potential to gain physically meaningful soils information using simple parameter estimation with few but appropriately timed remote sensing retrievals

    Sub-diffractional, volume-confined polaritons in a natural hyperbolic material: hexagonal boron nitride

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    Strongly anisotropic media where the principal components of the dielectric tensor have opposite signs are called hyperbolic. Such materials length exhibit unique nanophotonic properties enabled by the highly directional propagation of slow-light modes localized at deeply sub-diffractional scales. While artificial hyperbolic metamaterials have been demonstrated, they suffer from high plasmonic losses and require complex nanofabrication, which in turn induces the size-dependent limitations on optical confinement. The low-loss, mid-infrared, natural hyperbolic material, hexagonal boron nitride is an attractive alternative. We observe four series of multiple (up to seven) 'hyperbolic polariton' modes in boron nitride nanocones in two spectral bands. The resonant modes obey the predicted aspect ratio dependence and exhibit record-high quality factors (Q up to 283) in the strong confinement regime (lambda/86 in the smallest structures). These observations assert hexagonal boron nitride as a promising platform for studying novel regimes of light-matter interactions and nanophotonic device engineering

    Bimbingan dan Konseling Islam dengan Rational Emotive Behavior Therapy dalam Menangani Keterasingan Seorang Lesbi di Semolowaru Surabaya

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    Dalam skripsi terdapat dua fokus permasalahan yang dikaji, yaitu (1) Bagaimana proses Bimbingan dan Konseling Islam dengan Rational Emotive Behavior Therapy dalam menangani keterasingan seorang lesbi? (2) Bagaimana hasil pelaksanaan Bimbingan Konseling Islam dengan Rational Emotive Behavior Therapy dalam menangani keterasingan seorang lesbi? Dalam menjawab permasalahan tersebut, penelitian ini menggunakan metode penelitian kualitatif dengan analisis deskriptif komparatif yaitu membandingkan data teori dengan data yang ada di lapangan. Sedangkan dalam mengumpulkan data melalui observasi, wawancara dan dokumentasi, serta peneliti turun langsung kelapangan untuk mengumpulkan data. Setelah data terkumpul, analisa dilakukan untuk mengetahui proses serta hasil dengan membandingkan kondisi konseli sebelum dan sesudah pelaksanaan konseling. Proses yang dilakukan oleh konselor yang pertama adalah identifikasi masalah, diagnosis, prognosis, selanjutnya treatment dengan langkah pertama, konselor merubah pikiran-pikiran irrasionalnya kearah yang lebih rasional. Kedua, memperbaiki cara berfikir konseli dan menyadarkan bahwa pemikiran irrasional negatif dapat dirubah menjadi positif dan ketiga, memberi alternative pemecahan masalah, dengan member tugas-tugas dalam memperbaiki perilaku negatif konseli. Setelah proses konseli selesai yaitu langkah terakhir menindakk lanjuti masalah yang dialami oleh konseli setelah dilakukannya proses konseling. Hasil penelitian ini dapat disimpulkan bahwa masalah yang terjadi adalah keterasingan yang disebabkan pola pikir dan perilaku konseli yang negative. Perilaku tersebut sangat dilarang oleh norma agama. Dalam penelitian ini proses konseling yang dilaksanakan menggunakan Rational Emotive Behavior Therapy, yang mana peneliti menggunakan beberapa teknik untuk menangani masalah tersebut. Dengan pendekatan ini diharapkan konseli bisa menerima kenyataan pada perilakunya saat ini dan bisa merubah perilaku buruknya menjadi perilaku yang baik. Sedangkan hasil akhir dari proses konseling terhadap konseli dalam penelitian ini cukup berhasil yang mana hasil tersebut dapat diliihat dari adanya perubahan perilaku yang terjadi pada konseli yang sudah bisa berbaur dengan masyarakat dan meninggalkan perilaku negatifnya

    Pheochromocytoma presenting as recurrent urinary tract infections : a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Pheochromocytomas are rare, potentially fatal, neuroendocrine tumors of the adrenal medulla or extra-adrenal paraganglia. Their clinical presentation varies greatly from the classic triad of episodic headache, diaphoresis and tachycardia to include a spectrum of non-specific symptomatology.</p> <p>Case presentation</p> <p>A 43-year-old Caucasian woman was referred to us from primary care services with a three-month history of recurrent urinary tract infections on a background of hypertension, latent autoimmune diabetes of adulthood and autoimmune hypothyroidism. At 38 years she required insulin therapy. Despite medication compliance and dietary control, she reported a recent history of increased insulin requirements and uncontrolled hypertension with concomitant recurrent urinary tract infections. A renal ultrasound examination, to rule out underlying renal pathology, revealed an incidental 8cm right adrenal mass of both solid and cystic components. A subsequent computed tomography of her abdomen and pelvis confirmed a solid heterogeneous mass consistent with a pheochromocytoma. There were no other features suggestive of multiple endocrine neoplasia. Urinary collection over 24 hours revealed grossly elevated levels of catecholamines and metabolites. Following an open right adrenalectomy, our patient's insulin requirements were significantly reduced and her symptoms resolved. Two weeks post-operatively, an iodine-131-metaiodobenzylguanidine scintigraphy was negative for residual tumor and metastatic disease. Urinary catecholamine and metabolite concentrations were within the normal range at a follow-up six months later.</p> <p>Conclusion</p> <p>Pheochromocytoma is a rare catecholamine-producing tumor requiring a high index of suspicion for early diagnosis. Our case report serves to highlight the importance of considering pheochromocytoma as a differential diagnosis in the atypical setting of recurrent urinary tract infections and concomitant autoimmune disease.</p
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