2,614 research outputs found
Orbital Stability of Planets in Binary Systems: A New Look at Old Results
About half of all known stellar systems with Sun-like stars consist of two or
more stars, significantly affecting the orbital stability of any planet in
these systems. This observational evidence has prompted a large array of
theoretical research, including the derivation of mathematically stringent
criteria for the orbital stability of planets in stellar binary systems, valid
for the "coplanar circular restricted three-body problem". In the following, we
use these criteria to explore the validity of results from previous theoretical
studies.Comment: 3 pages, 1 figure; submitted to: Exoplanets: Detection, Formation and
Dynamics, IAU Symposium 249, eds. Y.-S. Sun, S. Ferraz-Mello, and J.-L. Zhou
(Cambridge: Cambridge University Press
A Pose-Sensitive Embedding for Person Re-Identification with Expanded Cross Neighborhood Re-Ranking
Person re identification is a challenging retrieval task that requires
matching a person's acquired image across non overlapping camera views. In this
paper we propose an effective approach that incorporates both the fine and
coarse pose information of the person to learn a discriminative embedding. In
contrast to the recent direction of explicitly modeling body parts or
correcting for misalignment based on these, we show that a rather
straightforward inclusion of acquired camera view and/or the detected joint
locations into a convolutional neural network helps to learn a very effective
representation. To increase retrieval performance, re-ranking techniques based
on computed distances have recently gained much attention. We propose a new
unsupervised and automatic re-ranking framework that achieves state-of-the-art
re-ranking performance. We show that in contrast to the current
state-of-the-art re-ranking methods our approach does not require to compute
new rank lists for each image pair (e.g., based on reciprocal neighbors) and
performs well by using simple direct rank list based comparison or even by just
using the already computed euclidean distances between the images. We show that
both our learned representation and our re-ranking method achieve
state-of-the-art performance on a number of challenging surveillance image and
video datasets.
The code is available online at:
https://github.com/pse-ecn/pose-sensitive-embeddingComment: CVPR 2018: v2 (fixes, added new results on PRW dataset
Cooperative Wool Marketing in South Dakota
The question of orderly marketing and cooperative marketing is foremost in the minds of agricultural leaders today. There is perhaps no agricultural commodity so susceptible to orderly marketing as wool. It is consumed throughout the whole year, but usually marketed by the producer in six weeks to two month\u27s time. This practice of marketing the greater part of the Nation\u27s wool clip in so short a time has encouraged the rapid growth of wool buyers and speculators, who buy up the wool when there is but little market demand and hold it to sell later when supplies are short. There are some 5,000 wool speculators operating today in the United States. A smaller number could in all probability handle the selling of the wool just as efficiently with less expense, if producers would change their methods of marketing. The producer of wool is entitled to the price paid by the consumer less the minimum cost of marketing. This will never be possible under the present methods of marketing practiced by most wool growers. It is possible, however, by marketing wool cooperatively, for here lies the opportunity of putting the wool into the hands of the manufacturer at a minimum cost. Through orderly marketing the wool can be sold when mill demand develops and these savings reflected to the producer of wool
Step in the Organization of a Cooperative Marketing Association
In almost every community there is someone agitating the formation of a cooperative marketing association. Sometimes it is just spite work on the part of the agitator, because he had a disagreement with the local buyer. On the other hand, many times the party in question has a genuine interest in cooperative marketing and really wants to see an organization formed for the good of the community. It is seldom advisable to call a meeting of farmers as soon as someone makes the suggestion of organizing a cooperative organization. As a rule it will be found, if a meeting is called right away, that the interest lies only with a few which discourages further work on the proposition. It is advisable to give the discussion plenty of time to grow so that one farmer will hear it from another. In this way interest will be created and plenty of time will be allowed for thinking the proposition over. After the discussion has reached a point where action seems advisable, someone interested can ask the county agent to call a meeting or if there is no county agent, can call it himself. All those who have expressed themselves as favorable should be asked to attend
Teacher Self-Efficacy and Student Achievement as Measured by North Carolina Reading and Math End-Of-Grade Tests.
Teachers continue to experience an increased sense of responsibility as it relates to job performance while still being required to produce at the same level with relation to student performance. This can cause an increase in personal stress and result in lowered feelings of self- worth, having a negative impact on service delivery to children and overall job performance.
Bandura (1997) defined self-efficacy as a judgment of one\u27s ability to organize and execute given types of performances. Furthermore, he suggests that the outcomes people anticipate depend largely upon their judgments of how well they will be able to perform in given situations. The same can be said for teachers in relation to their beliefs and attitudes toward their students\u27 overall performance.
The purpose of this quantitative study was to determine whether a relationship exists between teachers\u27 feeling of self-efficacy and their students\u27 overall achievement with respect to North Carolina Reading and Math End-Of-Grade tests. Surveys were administered to teachers in grades three through eight, in eight Pre-K through 8th grade schools. Data collected focused on teachers\u27 feeling of self-efficacy. This study employed qualitative data gathered from participant surveys. Participating teachers in this study are in high performing schools as defined by the North Carolina Department of Public Instruction. Their students have good academic records, coupled with high parental involvement (North Carolina Department of Public Instruction, 2010).
Six of the 14 comparisons within this study did not reveal a significant relationship between perceived teacher self-efficacy and North Carolina End-of-Grade reading and math test scores. However a relationship between perceived self-efficacy within gender did reveal that female participants tended to have higher perceived self-efficacy than that of the male participants. Male teacher participants tended to have higher North Carolina End-of-Grade reading test scores than those of female teacher participants. It was also discovered that each of the respondents, regardless of perceived self-efficacy score, had test results in both reading and math that were significantly higher than the state average. Finally it was also discovered that a relationship existed between teacher respondents with lower perceived self-efficacy scores and North Carolina math test scores
Case Studies of Habitable Trojan Planets in the System of HD 23079
We investigate the possibility of habitable Trojan planets in the HD 23079
star-planet system. This system consists of a solar-type star and a
Jupiter-type planet, which orbits the star near the outer edge of the stellar
habitable zone in an orbit of low eccentricity. We find that in agreement with
previous studies Earth-mass habitable Trojan planets are possible in this
system, although the success of staying within the zone of habitability is
significantly affected by the orbital parameters of the giant planet and by the
initial condition of the theoretical Earth-mass planet. In one of our
simulations, the Earth-mass planet is captured by the giant planet and thus
becomes a habitable moon.Comment: 24 pages, 8 figures, 3 tables; International Journal of Astrobiology
(in press
The Instability Transition for the Restricted 3-Body Problem. III. The Lyapunov Exponent Criterion
We establish a criterion for the stability of planetary orbits in stellar
binary systems by using Lyapunov exponents and power spectra for the special
case of the circular restricted 3-body problem (CR3BP). The centerpiece of our
method is the concept of Lyapunov exponents, which are incorporated into the
analysis of orbital stability by integrating the Jacobian of the CR3BP and
orthogonalizing the tangent vectors via a well-established algorithm originally
developed by Wolf et al. The criterion for orbital stability based on the
Lyapunov exponents is independently verified by using power spectra. The
obtained results are compared to results presented in the two previous papers
of this series. It is shown that the maximum Lyapunov exponent can be used as
an indicator for chaotic behaviour of planetary orbits, which is consistent
with previous applications of this method, particularly studies for the Solar
System. The chaotic behaviour corresponds to either orbital stability or
instability, and it depends solely on the mass ratio of the binary components
and the initial distance ratio of the planet relative to the stellar separation
distance. Our theoretical results allow us to link the study of planetary
orbital stability to chaos theory noting that there is a large array of
literature on the properties and significance of Lyapunov exponents. Although
our results are given for the special case of the CR3BP, we expect that it may
be possible to augment the proposed Lyapunov exponent criterion to studies of
planets in generalized stellar binary systems, which is strongly motivated by
existing observational results as well as results expected from ongoing and
future planet search missions.Comment: 10 pages, 8 figures, 3 tables; accepted by Astronomy and Astrophysic
Ultrasound mapping of lymph node and subcutaneous metastases in patients with cutaneous melanoma: Results of a prospective multicenter study
Background: Ultrasound (sonography, B-mode sonography, ultrasonography) examination improves the sensitivity in more than 25% compared to the clinical palpation, especially after surgery on the regional lymph node area. Objective: To evaluate the distribution of metastases during follow-up in the draining lymph node areas from the scar of primary to regional lymph nodes ( head and neck, supraclavicular, axilla, infraclavicular, groin) in patients with cutaneous melanoma with or without sentinel lymph node biopsy (SLNB) or former elective or consecutive complete lymph node dissection in case of positive sentinel lymph node (CLND). Methods: Prospective multicenter study of the Departments of Dermatology of the Universities of Homburg/Saar, Tubingen and Munich (Germany) in which the distribution of lymph node and subcutaneous metastases were mapped from the scar of primary to the lymphatic drainage region in 53 melanoma patients ( 23 women, 30 men; median age: 64 years; median tumor thickness: 1.99 mm) with known primary, visible lymph nodes or subcutaneous metastases proven by ultrasound and histopathology during the follow-up. Results: Especially in the axilla, infraclavicular region and groin the metastases were not limited to the anatomic lymph node regions. In 5 patients (9.4%) ( 4 of them were in stage IV) lymph node metastases were not located in the corresponding lymph node area. 32 patients without former SLNB had a time range between melanoma excision and lymph node metastases of 31 months ( median), 21 patients with SLNB had 18 months ( p < 0.005). In 11 patients with positive SLNB the time range was 17 months, in 10 patients with negative SLNB 21 months ( p < 0.005); in 32 patients with CLND the time range was 31 m< 0.005). In thinner melanomas lymph node metastases occurred later ( p < 0.05). Conclusions: After surgery of cutaneous melanoma, SLNB and CLND the lymphatic drainage can show significant changes which should be considered in clinical and ultrasound follow-up examinations. Especially for high-risk melanoma patients follow-up examinations should be performed at intervals of 3 months in the first years. Patients at stage IV should be examined in all regional lymph node areas clinically and by ultrasound. Copyright (c) 2006 S. Karger AG, Basel
Expression and Function of Bcl-2 Proteins in Melanoma
Bcl-2 proteins are critical regulators of mitochondrial membrane permeability and the proapoptotic mitochondrial pathway. The family encloses pro- and antiapoptotic factors encoded by over 15 genes, which frequently give rise to alternative splice products. Antiapoptotic, proapoptotic multidomain, and proapoptotic BH3-only proteins are characterized by the presence of at least one of four Bcl-2 homology domains (BH 1-4). Their expression and activities are controlled by survival pathways as MAP kinases and protein kinase B/Akt, which are in touch with a number of transcription factors. In melanoma, the mitochondrial apoptosis pathways and Bcl-2 proteins appear of particular importance for apoptosis resistance, which has been addressed in clinical trials applying antisense-Bcl-2. Overexpression or induction of proapoptotic Bcl-2 proteins as well as the use of small molecule mimetics for the proapoptotic BH3 domain are further promising strategies
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