11,265 research outputs found
Dynamic Credit Investment in Partially Observed Markets
We consider the problem of maximizing expected utility for a power investor
who can allocate his wealth in a stock, a defaultable security, and a money
market account. The dynamics of these security prices are governed by geometric
Brownian motions modulated by a hidden continuous time finite state Markov
chain. We reduce the partially observed stochastic control problem to a
complete observation risk sensitive control problem via the filtered regime
switching probabilities. We separate the latter into pre-default and
post-default dynamic optimization subproblems, and obtain two coupled
Hamilton-Jacobi-Bellman (HJB) partial differential equations. We prove
existence and uniqueness of a globally bounded classical solution to each HJB
equation, and give the corresponding verification theorem. We provide a
numerical analysis showing that the investor increases his holdings in stock as
the filter probability of being in high growth regimes increases, and decreases
his credit risk exposure when the filter probability of being in high default
risk regimes gets larger
Building Bridges Between Experts and Communities with Subscribe to Open
The worldâs problems â at local, national, regional, and global scales â require research assessment and solutions. However, trust in experts is low, public understanding of the scientific method is poor and misinformation/fake news is widespread. Researchers are often uncomfortable in the public eye. Research is specialized, problems are interdisciplinary. Academic institutions and academic publishers may not place a strong enough emphasis on outreach. We need more bridges from research and academia to policy makers, businesses and workers, educators and students, doctors and patients, the media, and civil society. We will give a brief description of a non-APC open access model, Subscribe to Open, that supports open access and open science and helps to guarantee the long-term scientific independence of research through a diversity of publishing models. Supporting the values of the scholarly reviews to the larger community and helping to meet the growing demand for open access publications, Annual Reviews first piloted Subscribe to Open in 2020. The model has been endorsed by cOAlitions S and has been adopted by a number of publishers who have come together to achieve fair and sustainable access to scholarly information
The Paradoxes of Poverty: Urban Space and Ideologies of Intervention in the Compassionate City of San Francisco
This dissertation examines a subset of urban poor women who live at the nexus of poverty and housing instability and who are exposed to multiple forms of violence and intense bodily suffering. I conducted two years of ethnographic research with a cohort of unstably housed women who have long histories of illicit drug use and who cycle between multiple single room occupancy hotels in two San Francisco neighborhoods. In this dissertation, I take as my analytic object the examination of the key institutional sites (what I call the local geography of hypermarginality) and the strategies for intervention deployed by the state in an attempt to ameliorate the conditions of extreme poverty. This dissertation has three central findings. First, even in a relatively rich resource context such as San Francisco, significant structural deficiencies and grave fragmentation of services limit the effectiveness of well-intentioned interventions. Second, institutional interventions administered by the left hand of the state,\u27 even as they draw on compassionate principles, are contradictory in nature and simultaneously deploy compassion and care with punitive and moralistic logics. Finally, this configuration results in a situation where women\u27s hypermarginality is reinforced by the institutions tasked with helping them.\u2
La Hermana Mayor in a Pandemic - A Collection of Poems based on Identity: Told From the Perspective of an Older Sister In a Latino Household During the Covid-19 Pandemic
A series of poems exploring the experience of an older sibling during the pandemic.https://digitalcommons.csumb.edu/hcom434_spring2021/1084/thumbnail.jp
Comparison of Discrete Part Verification Using Coordinate Measuring Machine and Articulated Arm Coordinate Measuring Machine
Quality assurance is key in manufacturing and assembling processes and is usually implemented by specifying and controlling tolerances and surface finish of important features, in discrete product manufacturing industry. Much of product verification and inspection for single parts and assemblies are considered to be non-value added, and hence, the processes and procedures must be constantly improved to achieve better savings in time and cost.
Coordinate Measuring Machines (CMMs) are the gold standard for geometry verification of parts in the industry, for their consistency and accuracy. Articulated Arm CMMs (AACMMs) use a scan/arm configuration, and as such are considered not accurate enough in part verification. And yet, they can result in many time-savings and ease of operation. If developed suitably, these can be used quite viably in situations that do not demand high accuracies. It is the aim of this thesis to investigate how the AACMMs compare to the traditional gantry CMMs in flatness verification. Flatness verification is the most fundamental of geometry verification employed in the industry. The success achieved in form verification can be extended to investigate further geometries, and AACMMs can be developed as an economical alternative to the more traditional CMMs in industry.
Specifically, this thesis investigated the flatness of surfaces generated by milling (roughing and finishing). Experiments were conducted on three rectangular blocks of Steel 1018 and three more of Aluminum 6061 of specific dimensions. The CMM employed was used to collect data using three sampling strategies: Hammersley, Halton Zaremba, and Aligned systematic methods. The AACMM was also used to collect the flatness data on each plate through a scan. A commercial GeomagicÂź Control Xâą was used to find flatness deviation between measured data and the CAD model for each of the rough and finish surfaces. Statistics from the distribution of gap distance and deviations were presented through the study. The accuracy was noted in each case.
The results developed verified that AACMM is not as accurate as of the traditional CMM in measuring flatness. All the same, the results were sufficient to suggest that AACMM can be used as a viable and faster alternative to the CMM in flatness verification
Age and growth of the highly exploited narrownose smooth-hound (Mustelus schmitti) (Pisces: Elasmobranchii)
The narrownose smoothhound (Mustelus schmitti) is the most exploited elasmobranch of Argentina, Brazil, and Uruguay and is considered endangered (IUCN Red List of Threatened Species). Providing information on age and growth can improve efforts for conservation of this species. Therefore, our objective was to provide accurate estimates of the age structure and growth parameters for narrownose smooth-hound from Anegada Bay, an important shark nursery area in Argentina. In vertebrae of narrownose smooth-hound, we observed a pattern of alternating opaque and translucent bands and a yearly periodicity in the deposition of this pattern. Ages determined from vertebral band counts ranged from 0 to 11 years. Calculated longevity and total natural mortality rates were 20.87 years and 0.19/year for females and 12.24 years and 0.26/year for males, respectively. This species reached a size of approximately 400 mm in total length in the initial year of growth, and the age at first maturity was 7.61 years for females and 6.79 years for males. The slow growth and late age at maturity of the narrownose smoothhound indicate a need for additional conservation measures to rebuild the population and achieve a sustainable fishery in the 3 countries in which it is distributed.Fil: Molina, Juan Manuel. Universidad Nacional del Sur; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Blasina, Gabriela Elizabeth. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto Argentino de OceanografĂa. Universidad Nacional del Sur. Instituto Argentino de OceanografĂa; ArgentinaFil: Lopez Cazorla, Andrea Cecilia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto Argentino de OceanografĂa. Universidad Nacional del Sur. Instituto Argentino de OceanografĂa; Argentin
CaracterĂsticas histolĂłgicas del Ăștero de Sympterygia acuta (Garman, 1877) y Sympterygia bonapartii (MĂŒller & Henle, 1841) (Chondrichthyes; Rajidae)
Los condrictios constituyen un clado sumamente conservado y vulnerable a la explotaciĂłn, que ha cobrado una importancia creciente en los Ășltimos años. Sin embargo, existe poca informaciĂłn sobre los aspectos morfolĂłgicos relacionados con la reproducciĂłn; tanto asĂ, que la estructura del Ăștero en hembras grĂĄvidas sĂłlo ha sido estudiada en profundidad en una especie ovĂpara. El presente trabajo describe las caracterĂsticas morfolĂłgicas, histolĂłgicas e histoquĂmicas del Ăștero de dos especies de RĂĄjidos del gĂ©nero Sympterygia a lo largo del ciclo de vida. Ambas especies presentan Ășteros pares que desembocan independientemente en un seno urogenital comĂșn. El Ăștero de las hembras inmaduras es filiforme, translĂșcido y poco especializado. Cuando se inicia el desarrollo sexual, todo el sistema genital exhibe un cambio direccional y progresivo. En todas las hembras estudiadas, independientemente del grado de madurez, se encontraron las mismas cuatro tĂșnicas a lo largo del Ăștero: una mucosa, compuesta por un epitelio de revestimiento y un corion, una submucosa, una muscular y una serosa. Los cambios mayores en la estructura del Ăștero a lo largo del ciclo de vida ocurren a nivel de la mucosa. En el Ăștero de hembras maduras, grĂĄvidas o no grĂĄvidas, se pueden reconocer tres regiones claramente diferenciables, craneal, media y caudal, que varĂan tanto en la estructura como en la afinidad histoquĂmica de la mucosa, asĂ como en el grosor de la tĂșnica muscular. Los resultados del presente trabajo se discuten en un contexto fisiolĂłgico, filogenĂ©tico y adaptativo.Chondrichthyes constitute a conserve and vulnerable clade of increasing importance. However, there is scarce knowledge about the morphological aspects of the reproduction, so that only one work exists about the structure of the gravid uterus of an oviparous species. The work presented here describes the morphological, histological and histochemical remarks of the uterus of two Rajids of the Sympterygia genus along the life cycle. Both species presented paired uteri that lead independently to a common urogenital sinus. The uteri of immature females are filiform, translucent and unspecialized tubes. When sexual development starts, all the genital system displays a transitional and progressive change. In all studied females, independently of the maturing stage, the same four layers were present all over the uterus: a mucosa, which comprises the lining epithelium and lamina propria, a submucosa, a muscular and a serosa. The major changes in the structure of the uterus along the life cycle occur in the mucosa. The uteri of mature, gravid and nongravid, females presents three distinguishable areas, cranial, medial and caudal, that vary both in the structure and histochemistry of the mucosa and in the thickness of the muscular layer. The results presented here are discussed in a physiological, adaptive and phylogenetic context.Fil: DĂaz Andrade, MarĂa Constanza. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca; Argentina. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia; ArgentinaFil: Lopez Cazorla, Andrea Cecilia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca; Argentina. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia; ArgentinaFil: GalĂndez, Elena Juana. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia; Argentin
Factors Associated With Financial Stress in the U.S.
Overall consumer debt reached $4.1 trillion in the U.S. (Federal Reserve Bank of New York, 2020). When individuals find themselves under challenging financial circumstances, they can become susceptible to emotional side effects and experience severe financial stress. It is, therefore, timely and important to examine to what extent certain financial stressors increase individualsâ financial stress levels. Using data from the 2018 National Financial Capability Study (NFCS), this study examined the relationship between financial stressors and financial stress and investigated factors associated with financial stress among adults in the U.S. In this study, financial stress level was measured by summing three variables: 1) thinking about my finances makes me feel anxious; 2) talking about my finances makes me feel stressed; and 3) worrying about running out of money in retirement. Financial stressors included five sources: 1) having too much debt, 2) receiving collector calls, 3) having unpaid medical bills, 4) experiencing income drop, and 5) the inability to pay bills. While focusing on the effect of financial stressors on levels of financial stress, we also included socioeconomic variables (e.g., race, age, gender, marital status, education, employment status, and income) in our empirical model. The OLS regression results indicate that all five financial stressors were statistically significant, suggesting that perceiving too much debt, receiving collector calls, having unpaid medical bills, experiencing income drop, and their inability to pay bills significantly increased their stress levels. The OLS results also showed that age, gender, employment status, and income were statistically significant in predicting the levels of financial stress. Understanding sociodemographic factors associated with financial stress could help financial practitioners and educators effectively guide and teach individuals with different socio-demographic backgrounds. These professionals could tailor their teaching and counseling programs to the benefit of those experiencing high levels of financial stressors and financial stress. Presentation Time: Wednesday, 3-4 p.m. Zoom link: https://usu-edu.zoom.us/j/82620839263?pwd=ei9iSlJHSkpGam96anBDeXozeGZidz0
MGF Approach to the Analysis of Generalized Two-Ray Fading Models
We analyze a class of Generalized Two-Ray (GTR) fading channels that consist
of two line of sight (LOS) components with random phase plus a diffuse
component. We derive a closed form expression for the moment generating
function (MGF) of the signal-to-noise ratio (SNR) for this model, which greatly
simplifies its analysis. This expression arises from the observation that the
GTR fading model can be expressed in terms of a conditional underlying Rician
distribution. We illustrate the approach to derive simple expressions for
statistics and performance metrics of interest such as the amount of fading,
the level crossing rate, the symbol error rate, and the ergodic capacity in GTR
fading channels. We also show that the effect of considering a more general
distribution for the phase difference between the LOS components has an impact
on the average SNR.Comment: 14 pages, 8 Figures and 2 Tables. This work has been accepted for
publication at IEEE Transactions on Wireless Communications. Copyright (c)
2014 IEEE. Personal use of this material is permitted. However, permission to
use this material for any other purposes must be obtained from the IEEE by
sending a request to [email protected]
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