Kramers-Kronig constrained variational analysis of optical spectra

A universal method of extraction of the complex dielectric function $\epsilon(\omega)=\epsilon_{1}(\omega)+i\epsilon_{2}(\omega)$ from experimentally accessible optical quantities is developed. The central idea is that $\epsilon_{2}(\omega)$ is parameterized independently at each node of a properly chosen anchor frequency mesh, while $\epsilon_{1}(\omega)$ is dynamically coupled to $\epsilon_{2}(\omega)$ by the Kramers-Kronig (KK) transformation. This approach can be regarded as a limiting case of the multi-oscillator fitting of spectra, when the number of oscillators is of the order of the number of experimental points. In the case of the normal-incidence reflectivity from a semi-infinite isotropic sample the new method gives essentially the same result as the conventional KK transformation of reflectivity. In contrast to the conventional approaches, the proposed technique is applicable, without readaptation, to virtually all types of linear-response optical measurements, or arbitrary combinations of measurements, such as reflectivity, transmission, ellipsometry {\it etc.}, done on different types of samples, including thin films and anisotropic crystals.Comment: 10 pages, 7 figure

Terahertz radiation driven chiral edge currents in graphene

We observe photocurrents induced in single layer graphene samples by illumination of the graphene edges with circularly polarized terahertz radiation at normal incidence. The photocurrent flows along the sample edges and forms a vortex. Its winding direction reverses by switching the light helicity from left- to right-handed. We demonstrate that the photocurrent stems from the sample edges, which reduce the spatial symmetry and result in an asymmetric scattering of carriers driven by the radiation electric field. The developed theory is in a good agreement with the experiment. We show that the edge photocurrents can be applied for determination of the conductivity type and the momentum scattering time of the charge carriers in the graphene edge vicinity.Comment: 4 pages, 4 figure, additional Supplemental Material (3 pages, 1 figure

Production Externalities in the Wood Furniture Industry in Central Java

This paper exploits micro firm level data to examine the impact of spatial clustering and links to foreign buyer networks on firm performance in the wood furniture industry in Central Java, Indonesia. The analysis is based on an annual manufacturing survey. We identify the impact of specialization of the cluster, diversification, and links to foreign buyer networks. For this purpose, a production function framework is developed. The results lend support to the view that clustering of large and medium scale specialized firms improves firm performance, while clustering of small scale specialized firms and clustering of diverse firms are not conducive to firm performance. We also find a clear positive association between involvement in exporting activities and firm performance

Magnetically induced spin-dependent photoemission from p-GaAs(Cs,O) into vacuum

A spin-dependent emission of optically oriented electrons from p-GaAs(Cs,O) into vacuum was experimentally observed in a magnetic field normal to the surface. This phenomenon is explained within the model which takes into account the jump in the electron g factor at the semiconductor-vacuum interface. Due to this jump, the effective electron affinity on the semiconductor surface depends on the mutual direction of optically oriented electron spins and the magnetic field, resulting in the spin-dependent photoemission. It is demonstrated that the observed effect can be used for the determination of spin diffusion length in semiconductors.Comment: 7 pages, 6 figures, published versio

Self‐consistent modeling of the large‐scale distortions in the geomagnetic field during the 24–27 September 1998 major magnetic storm

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94715/1/jgra17531.pd

Changing faces: Factors associated with the intention to pursue plastic surgery and practice in underserved areas

UNLABELLED: Improving the number of plastic and reconstructive surgeons who provide care to patients in underserved communities is critical to achieving health equity. We aimed to identify factors associated with graduating medical students\u27 intentions to pursue plastic surgery and practice in underserved areas. METHODS: De-identified data for US medical school graduates were obtained from the Association of American Medical Colleges for students who matriculated in academic years 2007-2008 and 2011-2012. Data collected included self-reported demographic and future practice intentions. Multivariate analysis was conducted to determine indicators of students\u27 interest in plastic surgery, and their intention to practice in underserved areas. RESULTS: Of the 57,307 graduating US medical students in our cohort who completed the Graduation Questionnaire, 532 (0.9%) reported an intention to pursue plastic surgery. Hispanic [adjusted odds ratio (aOR): 1.45; 95% confidence interval (95% CI), 1.07-1.98] and multiracial (aOR: 1.59; 95% CI, 1.03-2.45) students were more likely to pursue plastic surgery compared with other surgical specialties. Among students interested in plastic surgery, compared with non-Hispanic White students, Black (aOR: 6.15; 95% CI, 1.96-19.26) students were more likely to report intention to practice in underserved areas. Students with community-engagement experiences were more likely to report intention to practice in underserved areas. CONCLUSIONS: Diversity among medical trainees pursuing plastic and reconstructive surgery is critical for maintaining and expanding plastic surgery services rendered in underserved areas. These findings suggest that student demographics and experiences with community-engagement experiences are positive indicators of practicing in underserved communities

Клинический патоморфоз хронического описторхозного панкреатита

192 patients with chronic opisthorchosis pancreatitis (117 women (60,9%) and 75 men (39,1%) being under observation in Tomsk regional hepatologic center from 1970 till 2000) have been included in the protocol of retrospective cohort study. 36 patients (18,8%) have had a chronic pseudotumor-like pancreatitis. 133 patients (69,9%) have been diagnosed a chronic painful pancreatitis, 23 patients (12,0%) have been diagnosed a pancreatic cyst. Three basic forms of the chronic opisthorchosis pancreatitis have been suggested: a chronic painful pancreatitis, a chronic pseudotumor-like pancreatitis and a pancreatic cyst.В протокол ретроспективного когортного исследования вошли 192 пациента (117 (60,9%) женщин и 75 (39,1%) мужчин) с хроническим описторхозным панкреатитом, наблюдавшихся с 1970 по 2000 г. в Томском зональном гепатологическом центре. Хроническим псевдотуморозным панкреатитом страдали 36 пациентов (18,8%). У 133 (69,3%) пациентов был диагностирован хронический болевой панкреатит, кисты поджелудочной железы — у 23 (12,0%) больных. На основании патоморфологических и клинических особенностей предложено выделить три основные формы хронического описторхозного панкреатита: хронический болевой панкреатит, хронический псевдотуморозный панкреатит, кисты поджелудочной железы

Возможности криодеструкции в лечении цирроза печени

The aim of investigation was to evaluate the liver cryodestruction effect on the course of chronic hepatitis and hepatocirrhosis. Experimental part of the investigation has been fulfilled on 220 white mongrel rats with toxic hepatocirrhosis caused by carbon tetrachloride. Evaluation of hepatic parenchyma state has been done by the following criteria: factor of parenchyma normalization and factor of sclerotization. The comparison of these factors in the basic and control groups has revealed an evident positive dynamics in normalization of histological hepatic structure.Цель настоящего исследования — оценка влияния криодеструкции печени на течение хронического гепатита и цирроза. Экспериментальная часть исследования выполнена на 220 белых беспородных крысах с токсическим циррозом печени, вызванным четыреххлористым углеродом. Оценка состояния печеночной паренхимы проводилась по следующим критериям: коэффициент нормализации паренхимы, коэффициент склеротизации. Сравнение данных показателей в основной группе с показателями контрольной группы выявило явную положительную динамику в плане нормализации гистологической структуры печени

Криохирургия печени в эксперименте и клинике

The aim of the investigation – to study changes in hepatic tissue resulting from the influence of low temperatures (– 195,8 °C) in experiments and clinic. Hepatic tissue investigations in experiment have been carried out using electron and light microscopy. During the surgery instruments of original design have been used – cryoscalpels and cryodestructors. Experiments have been carried out on 45 sexually mature dogs of both sexes. Animals have been separated into 3 groups. On the first group (consisting of 12 animals), in the acute experiment, there have been studied features of cryoscalpel design characteristics. In the second series of experiment (on 22 dogs) there have been made a comparative study of hepatic resection using cryoultrasonic scalpel and simple surgical scalpel by means of the study of hemorrhage quantity. In 11 cases there have been studied hepatic morphological changes affected by cryoeffect. By the effect of low temperature ice crystals are appeared in hepatic tissue intracellularly and outside the cell, they cause mechanical injury and rupture of hepatic tissue. In 45 days connective tissue elements are formed at the place of cryodestruction. The use of cryoultrasonic scalpel in hepatic resection in the experiment decreases the hemorrhage quantity by 1,26 times as compared to the traditional methods. Positive experimental investigations allowed to use the low temperature with success in clinical practice at 253 patients with different localized hepatic diseases with 13 lethal outcomes (5,1%). Thus, the used cryosurgical technique during surgical operations allows to decrease significantly the hemorrhage, to eliminate parenchymatous bleeding and to prevent relapses of disease both at growths and at parasitic hepatic affection.Цель исследования — изучить изменения, происходящие в ткани печени под действием низкой температуры (–195,8 °С) в эксперименте и клинике. Исследование ткани печени в эксперименте проведены с использованием электронной и световой микроскопии. При выполнении операций применялись инструменты оригинальной конструкции — криоскальпели и криодеструкторы. Эксперименты выполнены на 45 половозрелых собаках обоего пола. Животные были разделены на 3 группы. На первой группе, состоящей из 12 животных, в остром опыте изучались особенности конструктивных особенностей криоскальпелей, во второй серии опытов (на 22 собаках) проводилось сравнительное изучение резекций печени с помощью криоультразвукового скальпеля и простого хирургического путем изучения величины кровопотери и в 11 случаях изучались морфологические изменения со стороны ткани печени на криовоздействие. Под действием низкой температуры в ткани печени внутрицеллюлярно и за пределами клетки образуются кристаллы льда, которые вызывают механическое повреждение и разрыв ткани печени, через 45 сут в месте криодеструкции образуются элементы соединительной ткани. Применение криоультразвукового скальпеля во время резекции печени в эксперименте снижает величину кровопотери в 1,26 раза по сравнению с традиционными методами.* Положительные экспериментальные исследования позволили с успехом применить низкую температуру в клинической практике у 253 больных с различными очаговыми заболеваниями печени с 13 летальными исходами (5,1%). Таким образом, применяемая криохирургическая техника позволяет во время оперативных вмешательств значительно снизить кровопотерю, устранить паренхиматозное кровотечение и предотвратить рецидивы заболевания как при опухолях, так и при паразитарном поражении печени