713 research outputs found
On the Relationships Between Real Consumption, Income, and Wealth
The existence of durable goods implies that the welfare flow from consumption cannot be directly associated with total consumption expenditures. As a result, tests of standard theories of consumption (such as the Permanent Income Hypothesis, or PIH) typically focus on nondurable goods and services. Specifically, these studies generally relate real consumption of nondurable goods and services to measures of real income and wealth, where the latter are deflated by a price index for total consumption expenditures. This paper demonstrates that this procedure is only valid under the assumption that real consumption of nondurables and services is a constant multiple of aggregate real consumption outlays---an assumption that represents a very poor description of U.S. data. The paper develops an alternative approach that is based on the observation that the ratio of these series has historically been stable in nominal terms, and uses this approach to examine two basic predictions of the PIH. We obtain significantly different results relative to the traditional approach.
The Trajectory of Wealth in Retirement
In this paper, we develop a measure of household resources that converts total financial, nonfinancial, and annuitized assets into an expected annual amount of wealth per person in retirement. We use this measure, which we call "annualized comprehensive wealth," to investigate spend-down behavior among a panel of older households in the Health and Retirement Study (HRS) from 1998 to 2006. Our analysis indicates that for most retired households, comprehensive wealth balances decline much more slowly than their remaining life expectancies, so that the predominate trend is for real annualized wealth actually to rise significantly with age over the course of retirement. Comparing the estimated age profiles for annualized wealth with profiles simulated from several different life cycle models, we find that a model that takes into account uncertain longevity, random medical expenses, and intended bequests lines up best with the broad patterns of rising annualized wealth in the HRS.Retirement wealth, life-cycle saving, mortality risk, precautionary saving, bequests, risk and uncertainty.
The Mediating Impact of Student Self-Efficacy: An Examination of Vocational and Academic Perceptions Among Students in Living-Learning Communities
The purpose of this study was to examine the influence of Living-Learning Communities on first-year students at a large Mid-Atlantic university. Students were asked to complete the Career Decision Self-Efficacy Scale and the Academic Major-Fit Scale in the beginning of their first semester in college, and then again mid-way through their second semester. The final results included 21 participants. No significant difference in career decision self-efficacy was found from the pre-test (prior to their experience in the living-leaning community) and the post-test. Two factors of perceived fit in the Academic Major-Fit Scale did show significant increases. These were academic major commitment, and academic major satisfaction. The results suggest that Living-Learning Communities do not directly aide students in their academic or career development
Impact of the earthworm Lumbricus terrestris (L.) on As, Cu, Pb and Zn mobility and speciation in contaminated soils
To assess the risks that contaminated soils pose to the environment properly a greater understanding of how soil biota influence the mobility of metal(loid)s in soils is required. Lumbricus terrestris L. were incubated in three soils contaminated with As, Cu, Pb and Zn. The concentration and speciation of metal(loid)s in pore waters and the mobility and partitioning in casts were compared with earthworm-free soil. Generally the concentrations of water extractable metal(loid)s in earthworm casts were greater than in earthworm-free soil. The impact of the earthworms on concentration and speciation in pore waters was soil and metal specific and could be explained either by earthworm induced changes in soil pH or soluble organic carbon. The mobilisation of metal(loid)s in the environment by earthworm activity may allow for leaching or uptake into biota
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Impacts of epigeic, anecic and endogeic earthworms on metal and metalloid mobility and availability
The introduction of earthworms into soils contaminated with metals and metalloids has been suggested
to aid restoration practices. Eisenia veneta (epigeic), Lumbricus terrestris (anecic) and Allolobophora
chlorotica (endogeic) earthworms were cultivated in columns containing 900 g soil with 1130, 345, 113
and 131 mg kg1 of As, Cu, Pb and Zn, respectively, for up to 112 days, in parallel with earthworm-free
columns. Leachate was produced by pouring water on the soil surface to saturate the soil and generate
downflow. Ryegrass was grown on the top of columns to assess metal uptake into biota. Different
ecological groups affected metals in the same way by increasing concentrations and free ion activities in
leachate, but anecic L. terrestris had the greatest effect by increasing leachate concentrations of As by
267%, Cu by 393%, Pb by 190%, and Zn by 429% compared to earthworm-free columns. Ryegrass
grown in earthworm-bearing soil accumulated more metal and the soil microbial community exhibited
greater stress. Results are consistent with earthworm enhanced degradation of organic matter leading
to release of organically bound elements. The degradation of organic matter also releases organic acids
which decrease the soil pH. The earthworms do not appear to carry out a unique process, but increase
the rate of a process that is already occurring. The impact of earthworms on metal mobility and
availability should therefore be considered when inoculating earthworms into contaminated soils as
new pathways to receptors may be created or the flow of metals and metalloids to receptors may be
elevated
Hydrogen induced abrupt structural expansion at high temperatures of a Ni32Nb28Zr30Cu10 membrane for H2 purification
Ni-Nb-Zr amorphous membranes, prepared by melt-spinning, show great potential for
replacing crystalline Pd-based materials in the field of hydrogen purification to an ultrapure grade
(>99.999%). In this study, we investigate the temperature evolution of the structure of an amorphous
ribbon with the composition Ni32Nb28Zr30Cu10 (expressed in atom %) by means of XRD and DTA
measurements. An abrupt structural expansion is induced between 240 and 300 °C by hydrogenation.
This structural modification deeply modifies the hydrogen sorption properties of the membrane,
which indeed shows a strong reduction of the hydrogen capacity above 270 °C
Comparing Low-Redshift Compact Dwarf Starbursts in the RESOLVE Survey with High-Redshift Blue Nuggets
We identify and characterize compact dwarf starburst galaxies in the RESOLVE survey, a volume-limited census of galaxies in the local universe, to probe the extent to which these galaxies are analogous to "blue nuggets," a class of intensely star-forming compact dwarf galaxies at high redshifts. We compare the masses, star formation rates, stellar surface mass densities, projected axis ratios, and environmental contexts of our sample to expectations and observations of blue nuggets. We find that low-z blue nugget candidates in the RESOLVE survey are statistically analogous to their high-z counterparts, exhibiting masses, colors, and specific star formation rates (SSFR) consistent with past high-z observations. However, we find that the stellar surface mass densities of our low-z sample are on order 10^8 solar masses per kiloparsec squared, or about a dex lower than what is predicted and observed for high-z blue nuggets. Cosmological simulations and semianalytical models in recent years have suggested that blue nuggets form as the result of intense compaction events driven by either converging cosmic gas streams or wet minor mergers. In either formation scenario, simulations have additionally suggested that these galaxies should exhibit some degree of rotation along their minor axes and prolate morphology. We report 3D spectroscopy observations of four of low-z blue nugget analogues, from which we construct high-resolution velocity fields, examining the evidence for minor axis or otherwise misaligned rotation. We observe evidence for double nuclei in ~85% of our low-z blue nugget analogue sample, strongly favoring a merger origin for these objects. We additionally observe dynamically complex kinematics in the 3D spectroscopy observations with multiple components of rotation which are spatially consistent with the double nuclei detections, further suggesting recent wet minor mergers as the dominant formation mechanism for our low-z blue nugget analogues.Bachelor of Scienc
Fenomeno erosivo in corrispondenza di pile di ponte allocate in prossimitĂ delle sponde.
La tesi presenta un analisi sperimentale riguardo gli effetti della posizione delle pile dei ponti lungo la sezione fluviale sia in presenza di materiale flottante (debris) che in sua assenza e la ricerca dell'equazione che descriva l'evoluzione temporale dello scavo.
La tesi è articolata in cinque capitoli:
-nel primo capitolo viene descritto lo stato attuale delle conoscenze riguardo l'erosione localizzata presso le pile dei ponti sia in presenza che in assenza di materiale flottante;
-il secondo capitolo descrive l'apparato sperimentale e le modalitĂ d'esecuzione delle prove;
-il terzo capitolo tratta l'elaborazione dei dati, la ricerca delle equazioni e la verifica delle stesse;
-il quarto capitolo confronta, in maniera qualitativa, la morfologia del fondo al termine deli vari test;
-il quinto capitolo chiude il lavoro e riassume le conclusioni
Therapist Mentalization and Patient Outcomes in the First Year of Psychotherapy
This study examined associations between therapist mentalization and patient outcomes in the first year of psychotherapy. Mentalization is the implicit and explicit consideration of mental states—one’s own as well as others’—and how such states mediate a person’s experiences in the world. It is conceptualized as existing on a scale of increasing complexity. This study sought to extend developmental research that has illustrated the positive influence of a parent’s mentalization on a child’s emotional well-being. Specifically, it was proposed that psychotherapy cases with high levels of therapist mentalization would have better patient outcomes than those with low levels of therapist mentalization.
To test this hypothesis, 17 therapy cases at a community clinic were followed for one year. In each case, the therapist completed the Patient-Therapist Adult Attachment Interview—Revised (PT-AAI-R) four months into treatment. From these interviews, each therapist’s level of mentalization was obtained via the Reflective Functioning (RF) Scale, which is a method for assessing the quality of mentalization in a narrative. This yielded a Therapist RF score for each case. Patient outcomes were assessed at baseline and 12 months. The patient outcomes assessed were symptoms that have been related to low mentalization—externalizing symptoms, emotion dysregulation, personality pathology, and attachment insecurity. Changes in these symptoms were expected to relate to Therapist RF scores.
Results indicated that Therapist RF was not related to symptom changes in the full sample. However, for patients with high levels of emotion dysregulation at baseline, high Therapist RF was associated with better outcomes in this symptom area. This was not the case for patients with low levels of emotion dysregulation at baseline. This finding suggests that Therapist RF might be particularly important in therapy with patients who have high levels of emotion dysregulation. Additionally, Therapist RF was elevated in the context of elevated personality pathology in patients, which suggests that high levels of personality pathology might be a catalyst for high Therapist RF, though Therapist RF was not associated with better outcomes for this symptom. A qualitative analysis of the PT-AAI-Rs of two therapists who each completed two interviews was performed. This analysis illustrated that Therapist RF scores were influenced by both the patient and the therapist in the dyads
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