2,491 research outputs found
Constraints on cosmic strings from ultracompact minihalos
Cosmic strings are expected to form loops. These can act as seeds for
accretion of dark matter, leading to the formation of ultracompact minihalos
(UCMHs). We perform a detailed study of the accretion of dark matter onto
cosmic string loops and compute the resulting mass distribution of UCMHs. We
then apply observational limits on the present-day abundance of UCMHs to derive
corresponding limits on the cosmic string tension . The bounds are
strongly dependent upon the assumed distribution of loop velocities and their
impacts on UCMH formation. Under the assumption that a loop can move up to a
thousand times its own radius and still form a UCMH, we find a limit of
. We show, in opposition to previous results, that
strong limits on the cosmic string tension are not obtainable from UCMHs when
more stringent (and realistic) requirements are placed on loop velocities.Comment: 14 pages, 3 figure
Uncertain Electric Vehicle Incentives :Does It Affect Vehicle Choice? An exploratory study on how uncertainty impacts the sale of new electric vehicles, using media intensity as a measure of uncertainty
This thesis explores whether uncertainty regarding electric vehicle incentives impacts
electric vehicle sales. In the late 1990s, the first incentives for electric vehicles were
implemented, and throughout the 2000s, more benefits were introduced. Since then, there
have been several policy changes regarding the incentives, and there is an ongoing political
and public debate about whether these incentives should be continued or not.
To measure uncertainty, we constructed uncertainty indexes. The indexes are based on
newspaper frequency, and they measure monthly uncertainty regarding various electric
vehicle incentives. They are standardized and will take a value between 0 and 100.
This uncertainty measurement was used in three case analyses to see if we could find
any relationship between uncertainty and the sale of new electric vehicles. We conducted
a time series analysis in an attempt to see how uncertainty regarding electric vehicle
incentives, in general, has affected sales in the last decade. In this first attempt, we find
no evidence that there is a relationship in the data. Furthermore, we conducted two
specific case analyses with the difference-in-differences research method. In these analyses,
we wanted to investigate how different levels of uncertainty regarding toll road fees and
parking fees affected the sale. However, as in the first case, we do not get any statistically
significant results, and we cannot conclude whether the uncertainty affects the sale.
Despite the inconclusive results, the thesis provides a framework for decision-making
and offers a thorough literature review of what influences consumers' vehicle choices.
Furthermore, we use this insight to discuss possible explanations for our results both
rational and psychological explanations.
As far as we know, no previous empirical studies have been conducted on the relationship
between uncertainty regarding incentives and sales. We hope this thesis will contribute
with some insight and inspire to further research on the subject.nhhma
Ensaio de Proficiência Interlaboratorial para Contagem de Células Somáticas em Leite.
bitstream/item/31512/1/comunicado-225.pd
Amostras Piloto no Controle da Qualidade dos Resultados da Composição Centesimal de Leite.
bitstream/item/31510/1/comunicado-223.pd
Validação da espectroscopia de ressonância magnética nuclear (RMN) na determinação do teor de óleo em sementes de mamona.
bitstream/item/31248/1/comunicado-153.pd
Caracterização da variabilidade genética de populações locais de pimenta dedo-de-moça, utilizando marcadores RAPD.
bitstream/item/30461/1/boletim-80.pd
Cardiovascular morbidity and the use of inhaled bronchodilators
We used the Manitoba Health database to examine the relationship between use of inhaled respiratory drugs in people with chronic obstructive respiratory diseases and cardiovascular hospitalizations from 1996 through 2000. The drugs examined were beta agonists [BA], ipratropium bromide IB, and inhaled steroids (ICS). End points were first hospitalizations for supraventricular tachycardia, myocardial infarction, heart failure or stroke. A nested case control analysis was employed comparing people with and without cardiovascular events. Cases and controls were matched for gender and age, and conditional logistic regression was used in multivariate analysis considering other respiratory drugs, respiratory diagnosis and visit frequency, non-respiratory, non-cardiac comorbidities, and receipt of drugs for cardiovascular disease
Divergência genética entre acessos do banco ativo de germoplasma de cebola da Embrapa Clima Temperado revelada por marcadores RAPD.
bitstream/item/30465/1/boletim-81.pd
- …