741 research outputs found
Exploring strong-field deviations from general relativity via gravitational waves
Two new observational windows have been opened to strong gravitational
physics: gravitational waves, and very long baseline interferometry. This
suggests observational searches for new phenomena in this regime, and in
particular for those necessary to make black hole evolution consistent with
quantum mechanics. We describe possible features of "compact quantum objects"
that replace classical black holes in a consistent quantum theory, and
approaches to observational tests for these using gravitational waves. This is
an example of a more general problem of finding consistent descriptions of
deviations from general relativity, which can be tested via gravitational wave
detection. Simple models for compact modifications to classical black holes are
described via an effective stress tensor, possibly with an effective equation
of state. A general discussion is given of possible observational signatures,
and of their dependence on properties of the colliding objects. The possibility
that departures from classical behavior are restricted to the near-horizon
regime raises the question of whether these will be obscured in gravitational
wave signals, due to their mutual interaction in a binary coalescence being
deep in the mutual gravitational well. Numerical simulation with such simple
models will be useful to clarify the sensitivity of gravitational wave
observation to such highly compact departures from classical black holes.Comment: 20 pages, 9 figures. v2: references and CERN preprint number adde
Tentative Detection of the Nitrosylium Ion in Space
We report the tentative detection in space of the nitrosylium ion, NO.
The observations were performed towards the cold dense core Barnard 1-b. The
identification of the NO =2--1 line is supported by new laboratory
measurements of NO rotational lines up to the =8--7 transition
(953207.189\,MHz), which leads to an improved set of molecular constants: \,MHz, \,kHz, and \,MHz. The profile of the feature assigned to NO exhibits two
velocity components at 6.5 and 7.5 km s, with column densities of and cm, respectively. New
observations of NO and HNO, also reported here, allow to estimate the following
abundance ratios: (NO)/(NO), and
(HNO)/(NO). This latter value provides important constraints
on the formation and destruction processes of HNO. The chemistry of NO and
other related nitrogen-bearing species is investigated by the means of a
time-dependent gas phase model which includes an updated chemical network
according to recent experimental studies. The predicted abundance for NO
and NO is found to be consistent with the observations. However, that of HNO
relative to NO is too high. No satisfactory chemical paths have been found to
explain the observed low abundance of HNO. HSCN and HNCS are also reported here
with an abundance ratio of . Finally, we have searched for NNO,
NO, HNNO, and NNOH, but only upper limits have been obtained for
their column density, except for the latter for which we report a tentative
3- detection.Comment: To appear in the Astrophysical Journal October 20, 201
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High Frequency (4th order) Sequence Stratigraphy of Early Miocene Deltaic Shorelines, Offshore Texas and Louisiana
DOE-NETL Award Numbers DE-FE0026083 and DEFE0029487Bureau of Economic Geolog
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Disputed Spaces : Concheras, Shrimp Aquaculture, and Conservation in the Mangrove Forests of Southern Esmeraldas, Ecuador
The mangrove ecosystem has served as a life-support system to large populations of coastal dwellers in Ecuador for many generations. Diverse communities comprised of multi-racial and multi-ethnic groups have formed along the edge of the mangrove forests throughout the Ecuadorian coast. These groups self-identify as being part of an “ancestral” pueblo of the mangrove ecosystem. As is the case of many rural frontier lands in the Global South, the coastal regions of Ecuador have experienced an influx of various large-scale economic activities over recent decades that resulted in a vast biophysical transformation of these landscapes. While these developments have environmental implications, they have also resulted in complex social and cultural impacts. This dissertation examines the people-mangrove relations of the inhabitants of a community in southern Esmeraldas, Ecuador that has historically relied on mangrove resources to subsist. Semi-structured interviews, household surveys, participant observation, and geolocational data were collected in Bolívar, a mangrove community in Muisne, Esmeraldas to gain an understanding of the ways in which the community perceives, utilizes, and interacts with the mangrove forests. It further identifies how the introduction of new spatialities to these mangrove spaces – shrimp aquaculture and mangrove conservation – affect the spatiality of the ancestral mangrove users. An examination of these contemporaneous spatialities reveals that they conflict, converge, and complement one another in variegated and often insidious ways. This dissertation argues that because the mangrove forests are being appropriated for the extraction of resources, whether through shrimp aquaculture or state-led conservation, the introduction of these spatialities pose comparable social and cultural impacts on the mangrove users who have historically depended on mangrove resources. Loss of access to mangroves has resulted in the loss of spaces traditionally used by the community to sustain nutritional needs, to carry out livelihood practices, and to foster cultural and personal identity, which has resulted in complex social and cultural changes Furthermore, the findings of this dissertation indicate that the impacts of these processes are not evenly spread among all mangrove users, but rather further marginalize vulnerable groups, particularly the women of the community
Discrimination learning with variable stimulus 'salience'.
BACKGROUND: In nature, sensory stimuli are organized in heterogeneous combinations. Salient items from these combinations 'stand-out' from their surroundings and determine what and how we learn. Yet, the relationship between varying stimulus salience and discrimination learning remains unclear. PRESENTATION OF THE HYPOTHESIS: A rigorous formulation of the problem of discrimination learning should account for varying salience effects. We hypothesize that structural variations in the environment where the conditioned stimulus (CS) is embedded will be a significant determinant of learning rate and retention level. TESTING THE HYPOTHESIS: Using numerical simulations, we show how a modified version of the Rescorla-Wagner model, an influential theory of associative learning, predicts relevant interactions between varying salience and discrimination learning. IMPLICATIONS OF THE HYPOTHESIS: If supported by empirical data, our model will help to interpret critical experiments addressing the relations between attention, discrimination and learning
Producción anual de Carne/HA en pastoreo rotacional en los zacates ferrer, estrella de áfrica y señal, con y sin fertilizantes, en Hueytamalco, Pue.
En el Centro Experimental Pecuario de Hueytamalco, Pue., se investigó en los zacates introducidos Ferrer, Cynodon dactylon; Señal, Brachiaria brizantha, y Estrella de África, Cynodon plectostachyus, su potencial de producción anual y estacional de carne. Se utilizó un diseño completamente al azar con diferente número de animales por tratamiento: 0 y 150 kg N/ha con una carga de dos y cuatro animales/ha, respectivamente. La respuesta a la fertilización fue altamente significativa, obteniendo en promedio 618 kg carne/ha en los zacates fertilizados y 325 kg carne/ha en los zacates no fertilizados. La fertilización permitió un incremento de 92% en producción de carne/ha. Los zacates Ferrer, Estrella y Señal con cuatro animales/ha y 150 kg N/ha alcanzaron en un año de pastoreo una producción de 636, 583 y 637 kg carne/ha con una ganancia diaria promedio de 437, 400 y 438 g. respectivamente, diferencias que no fueron estadísticamente significativas (
Trends in the prevalence and distribution of HTLV-1 and HTLV-2 infections in Spain
<p>Abstract</p> <p>Background</p> <p>Although most HTLV infections in Spain have been found in native intravenous drug users carrying HTLV-2, the large immigration flows from Latin America and Sub-Saharan Africa in recent years may have changed the prevalence and distribution of HTLV-1 and HTLV-2 infections, and hypothetically open the opportunity for introducing HTLV-3 or HTLV-4 in Spain. To assess the current seroprevalence of HTLV infection in Spain a national multicenter, cross-sectional, study was conducted in June 2009.</p> <p>Results</p> <p>A total of 6,460 consecutive outpatients attending 16 hospitals were examined. Overall, 12% were immigrants, and their main origin was Latin America (4.9%), Africa (3.6%) and other European countries (2.8%). Nine individuals were seroreactive for HTLV antibodies (overall prevalence, 0.14%). Evidence of HTLV-1 infection was confirmed by Western blot in 4 subjects (prevalence 0.06%) while HTLV-2 infection was found in 5 (prevalence 0.08%). Infection with HTLV types 1, 2, 3 and 4 was discarded by Western blot and specific PCR assays in another two specimens initially reactive in the enzyme immunoassay. All but one HTLV-1 cases were Latin-Americans while all persons with HTLV-2 infection were native Spaniards.</p> <p>Conclusions</p> <p>The overall prevalence of HTLV infections in Spain remains low, with no evidence of HTLV-3 or HTLV-4 infections so far.</p
Let’s sculpt it! Experiencing the role of context in coaching
This exercise aims to familiarize students with the under-discussed topic
of the role of context in coaching through a physical activity. It consists
of a Group Sculpture – a combination of Socio-drama, Systemic
Constellation, Social Presencing Theater – drawing from a coaching case
of an ethical dilemma, using the placement and arrangement of
participants to represent the stakeholders and context (economic, legal,
sociological, etc.). The visual and embodied representation aims to raise
awareness and develop understanding of the invisible, but often felt
contextual factors at play in coaching, to generate reflection about their
influence, and to offer insights on how to identify and embrace them.
This activity is primarily aimed for coaching educators and supervisors,
but a slightly adapted version could expand its benefits to a more
general audience of managers and leaders
Symmetry breaking perturbations and strange attractors
The asymmetrically forced, damped Duffing oscillator is introduced as a
prototype model for analyzing the homoclinic tangle of symmetric dissipative
systems with \textit{symmetry breaking} disturbances. Even a slight fixed
asymmetry in the perturbation may cause a substantial change in the asymptotic
behavior of the system, e.g. transitions from two sided to one sided strange
attractors as the other parameters are varied. Moreover, slight asymmetries may
cause substantial asymmetries in the relative size of the basins of attraction
of the unforced nearly symmetric attracting regions. These changes seems to be
associated with homoclinic bifurcations. Numerical evidence indicates that
\textit{strange attractors} appear near curves corresponding to specific
secondary homoclinic bifurcations. These curves are found using analytical
perturbational tools
The Role of Individual Variables, Organizational Variables and Moral Intensity Dimensions in Libyan Management Accountants’ Ethical Decision Making
This study investigates the association of a broad set of variables with the ethical decision making of management accountants in Libya. Adopting a cross-sectional methodology, a questionnaire including four different ethical scenarios was used to gather data from 229 participants. For each scenario, ethical decision making was examined in terms of the recognition, judgment and intention stages of Rest’s model. A significant relationship was found between ethical recognition and ethical judgment and also between ethical judgment and ethical intention, but ethical recognition did not significantly predict ethical intention—thus providing support for Rest’s model. Organizational variables, age and educational level yielded few significant results. The lack of significance for codes of ethics might reflect their relative lack of development in Libya, in which case Libyan companies should pay attention to their content and how they are supported, especially in the light of the under-development of the accounting profession in Libya. Few significant results were also found for gender, but where they were found, males showed more ethical characteristics than females. This unusual result reinforces the dangers of gender stereotyping in business. Personal moral philosophy and moral intensity dimensions were generally found to be significant predictors of the three stages of ethical decision making studied. One implication of this is to give more attention to ethics in accounting education, making the connections between accounting practice and (in Libya) Islam. Overall, this study not only adds to the available empirical evidence on factors affecting ethical decision making, notably examining three stages of Rest’s model, but also offers rare insights into the ethical views of practising management accountants and provides a benchmark for future studies of ethical decision making in Muslim majority countries and other parts of the developing world
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