3,231 research outputs found
Squark Pair Production in the MSSM with Explicit CP Violation
We analyze effects of the CP-odd soft phases in the MSSM on the
pair-productions of colored superpartners in pp collisions at the LHC energies.
We find that, among all pair-production processes, those of the scalar quarks
in the first and second generations are particularly sensitive to the CP-odd
phases, more precisely, to the phases of the gluinos and neutralinos. We
compute pair-production cross sections, classify various production modes
according to their dependencies on the gluino and neutralino phases, perform a
detailed numerical analysis to determine individual as well as total cross
sections, and give a detailed discussion of EDM bounds. We find that
pair-productions of first and second generation squarks serve as a viable probe
of the CP violation sources in the gaugino sector of the theory even if
experiments cannot determine chirality, flavor and electric charge of the
squarks produced.Comment: 36 pp, 14 ps figures, 1 table, Corrected the cross sections; mild
changes in numerical results; conclusion unchange
Firm dynamics, job turnover, and wage distributions in an open economy
This paper explores the effects of tariffs, trade costs, and firing costs on firm dynamics and labor markets outcomes. The analysis is based on a general equilibrium model with labor market search frictions, wage bargaining, firing costs, firm-specific productivity shocks, and endogenous entry/exit decisions. Firing costs reduce firms' profits and discourage them from quickly adjusting their employment levels in response to idiosyncratic shocks. Tariffs and other trade costs reduce rents for efficient firms and increase rents for inefficient firms, as in Melitz (2003). These well-known effects interact with idiosyncratic productivity shocks and with scale economies in hiring costs to determine the equilibrium size distribution of firms, entry/exit rates, job turnover rates, rate of informality, and cross-firm wage distributions.
Accuracy of digital panoramic radiographs on the vertical measurements of dental implants
Amaç: Panoramik radyografi (PR), dental ve iliskili yapilari degerlendirmek için en sik kullanilan tekniktir. Bu çalismanin amaci, dental implant tedavisinin planlanmasinda panoramik radyografik görüntülerin (PRI) dogrulugunu ve anterior, premolar ve posterior bölgeler için bir panoramik cihazin büyütme oranini belirlemekti. Gereç ve Yöntem: Implant cerrahisi sonrasi PRI'lari alinmis olan 83 hasta çalismaya dahil edildi. önceden dikey uzunluklari bilinen toplam 240 adet dental implant (53 anterior, 69 premolar ve 118 molar bölge), PRI'nin büyütme oranini ve dogrulugunu belirlemek için, panoramik sistemin ölçüm araçlari kullanilarak ameliyat sonrasi radyografik görüntüler üzerinde tekrar ölçüldü. Verilerin normal dagilima sahip olmasi nedeniyle, istatistiksel analiz için eslestirilmis t testi kullanildi (p < 0,05). üç bölgenin büyütme orani, implantlarin ölçülen dikey uzunlugunun, implantlarin gerçek dikey uzunluguna orani bulunarak hesaplandi. Bulgular: Implantlarin gerçek dikey uzunlugu ve PRI'dan ölçülen dikey uzunlugu arasinda istatistiksel olarak anlamli fark bulundu (p < 0,05). Bununla birlikte, korelasyon orani tüm bölgeler için 1'e yakin bulundu. Implantlarin gerçek dikey uzunlugu ve PRI'den ölçülen dikey uzunlugu arasindaki fark, ön bölge için 0.50 mm, premolar bölge için 0,97 mm ve molar bölge için 0,83 mm idi. Cliniview™ (Instrumentarium Sti., Tuusula, FINLANDIYA) yazilimi tarafindan düzeltilen panoramik sistemin büyütme orani, tüm bölgeler için 1 civarinda bulundu. Sonuçlar: PRI'lar, kolay ulasilabilir olmalari ve düsük radyasyon dozlari sayesinde, implant cerrahisi planlamasindaki dikey ölçümler için 1 mm'lik güven araligi ile kullanilabilir. © Cumhuriyet University Faculty of Dentistry 2018.Objectives: Panoramic radiography (PR) is the most commonly used technique to evaluate the dental and associated structures. The aim of this study was to determine the accuracy of panoramic radiographic images (PRIs) in planning the dental implant treatment and the magnification rate of a panoramic device for anterior, premolar and posterior regions. Materials and Methods: Eighty-eight patients with PRIs were taken after implant surgery were included to the study. A total of 240 dental implants (53 anterior, 69 premolar, and 118 molar regions) of which actual vertical lengths were known, were re-measured on post-operative radiographic images using the scaling tools of the panoramic system to determine the magnification rate and the accuracy of PRIs. Because the data had normal distribution, the paired t test was used for the statistical analysis (p < 0.05). The magnification rates of the three regions were calculated as the ratio of the radiographically measured vertical length of the implants to the actual vertical length of the implants. Results: A statistically significant difference was found between the actual and measured vertical length of the implants on the PRI (p < 0.05). However, the correlation rate was found close to 1 for all regions. The difference between the actual and measured vertical length of the implants on the PRI was 0.50 mm for the anterior region, 0.97 mm for the premolar region, and 0.83 mm for the molar region. The magnification rate of the panoramic system corrected by Cliniview™ (Instrumentarium Corp., Tuusula, FINLAND) software was found around 1 for all the regions. Conclusions: Due to their readily accessible nature and low radiation dose, PRIs can be used in implant surgery for vertical measurements with 1 mm confidence interval. © Cumhuriyet University Faculty of Dentistry 2018
Magneto Acoustic Spin Hall Oscillators
This paper introduces a novel oscillator that combines the tunability of spin
Hall-driven nano oscillators with the high quality factor (Q) of high overtone
bulk acoustic wave resonators (HBAR), integrating both reference and tunable
oscillators on the same chip with CMOS. In such magneto acoustic spin Hall
(MASH) oscillators, voltage oscillations across the magnetic tunnel junction
(MTJ) that arise from a spin-orbit torque (SOT) are shaped by the transmission
response of the HBAR that acts as a multiple peak-bandpass filter and a delay
element due to its large time constant, providing delayed feedback. The
filtered voltage oscillations can be fed back to the MTJ via a) strain, b)
current, or c) magnetic field. We develop a SPICE-based circuit model by
combining experimentally benchmarked models including the stochastic
Landau-Lifshitz-Gilbert (sLLG) equation for magnetization dynamics and the
Butterworth Van Dyke (BVD) circuit for the HBAR. Using the self-consistent
model, we project up to 50X enhancement in the oscillator linewidth with
Q reaching up to 52825 at 3 GHz, while preserving the tunability by locking the
STNO to the nearest high Q peak of the HBAR. We expect that our results will
inspire MEMS-based solutions to spintronic devices by combining attractive
features of both fields for a variety of applications
Domestic Road Infrastructure and International Trade: Evidence from Turkey
Poor domestic transportation infrastructure in developing countries is often cited as an important impediment for accessing international markets. Yet, evidence on how transportation infrastructure improvements affect the volume and composition of exports is scarce. Drawing on the large-scale public investment in expressways undertaken in Turkey during the 2000s, this paper contributes to our understanding of how internal trade costs affect regional exports and specialization. Two results emerge. First, we estimate that this road infrastructure project accounts for 15 percent of the export increase from interior regions, generating a 10-year discounted stream of additional export revenues that amount to between 9 and 14 percent of the value of the investment. Second, while the exports of all industries within a given region increase in response to improvements in connectivity to the international gateways of the country, the magnitude of this increase is larger the more time sensitive an industry is. Accordingly, we also observe an increase in the regional employment and revenue shares of such industries. Our results support the hypothesis that internal trade costs can be a determinant of international specialization and comparative advantage
Network models and biproportional rounding for fair seat allocations in the UK elections
Systems for allocating seats in an election offer a number of socially and mathematically interesting problems. We discuss how to model the allocation process as a network flow problem, and propose a wide choice of objective functions and allocation schemes. Biproportional rounding, which is an instance of the network flow problem, is used in some European countries with multi-seat constituencies. We discuss its application to single seat constituencies and the inevitable consequence that seats are allocated to candidates with little local support. However, we show that variants can be selected, such as regional apportionment, to mitigate this problem. In particular, we introduce a parameter based family of methods, which we call Balanced Majority Voting, that can be tuned to meet the public's demand for local and global ``fairness''. Using data from the 2010 and 2015 UK General Elections, we study a variety of network models and implementations of biproportional rounding, and address conditions of existence and uniqueness
Shipping inside the Box: Containerization and Trade
We quantify the effect of container technology on transport costs and trade by estimating the modal choice between containerization and breakbulk shipping using micro-level trade data. The model is motivated by novel facts that relate container usage to shipment, destination and firm characteristics. We find container transport to have a higher first-mile cost and a lower distance elasticity, making it cost effective in longer distances. At the median distance across all country pairs, the box decreases variable shipping costs between 16 to 22 percent. The box explains a significant amount of the global trade increase since its inception: a quantitative exercise suggests that Turkish and U.S. maritime exports would have been about two-thirds of what they are today in the absence of containers
Firm Dynamics, Job Turnover, and Wage Distributions in an Open Economy
This paper explores the combined effects of reductions in trade frictions, tariffs, and firing costs on firm dynamics, job turnover, and wage distributions. It uses establishment-level data from Colombia to estimate an open economy dynamic model that links trade to job flows in a new way. The fitted model captures key features of Colombian firm dynamics and labor market outcomes, as well changes in these features during the past 25 years. Counterfactual experiments imply that integration with global product markets has increased both average income and job turnover in Colombia. In contrast, the experiments find little role for this country's labor market reforms in driving these variables. The results speak more generally to the effects of globalization on labor markets in Latin America and elsewhere
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