1,066 research outputs found
Effects of shear on eggs and larvae of striped bass, morone saxatilis, and white perch, M. americana
Shear stress, generated by water movement, can kill fish eggs and larvae by causing rotation or deformation. Through the use of an experimental apparatus, a series of shear
(as dynes/cm2)-mortality equations for fixed time exposures were generated for striped bass and white perch eggs and larvae. Exposure of striped bass eggs to a shear level of 350 dynes/cm2 kills 36% of the eggs in 1 min; 69% in 2 min, and 88% in 4 min; exposure of larvae to 350 dynes/cm2 kills 9.3% in 1 min, 30.0% in 2 min, and 68.1% in 4 min. A shear level of 350 dynes/cm2 kills 38% of the white perch eggs in 1 min, 41% in 2 min, 89% in 5 min, 96% in 10 min, and 98% in 20 min. A shear level of 350 dynes/cm2 applied to white perch larvae destroys 38% of the larvae in 1 min, 52% in 2 min, and 75% in 4 min. Results are experimentally used in conjunction with the determination of shear levels in the Chesapeake and Delaware Canal and ship movement for the estimation of fish egg and larval mortalities in the field
Birds of a feather locate together? Foursquare checkins and personality homophily
In this paper we consider whether people with similar personality traits have a preference for common locations. Due to the difficulty in tracking and categorising the places that individuals choose to visit, this is largely unexplored. However, the recent popularity of location-based social networks (LBSNs) provides a means to gain new insight into this question through checkins - records that are made by LBSN users of their presence at specific street level locations. A web-based participatory survey was used to collect the personality traits and checkin behaviour of 174 anonymous users, who, through their common check-ins, formed a network with 5373 edges and an approximate edge density of 35%. We assess the degree of overlap in personality traits for users visiting common locations, as detected by user checkins. We find that people with similar high levels of conscientiousness, openness or agreeableness tended to have checked-in locations in common. The findings for extraverts were unexpected in that they did not provide evidence of individuals assorting at the same locations, contrary to predictions. Individuals high in neuroticism were in line with expectations, they did not tend to have locations in common. Unanticipated results concerning disagreeableness are of particular interest and suggest that different venue types and distinctive characteristics may act as attractors for people with particularly selective tendencies. These findings have important implications for decision-making and location
Complexes of Pd(II) and Pt(II) with 9-Aminoacridine: Reactions with DNA and Study of Their Antiproliferative Activity
Four new metal complexes {M = Pd(II) or Pt(II)} containing the ligand 9-aminoacridine (9AA) were
prepared. The compounds were characterized by FT-IR and 1H, 13C, and 195Pt NMR spectroscopies. Crystal structure of the palladium complex of formulae [Pd(9AA)(Ό-Cl)]2 · 2DMF was determined by X-ray diffraction. Two 9-acridine molecules in the imine form bind symmetrically to the metal ions in a bidentate fashion through the imine nitrogen atom and the C(1) atom of the aminoacridine closing a new five-membered ring. By reaction with phosphine or pyridine, the Cl bridges broke and compounds with general formulae [Pd(9AA)Cl(L)] (where L = PPh3 or py) were formed. A mononuclear complex of platinum of formulae [Pt(9AA)Cl(DMSO)] was
also obtained by direct reaction of 9-aminoacridine and the complex [PtCl2(DMSO2]. The capacity of the compounds to modify the secondary and tertiary structures of DNA was evaluated by means of circular dichroism and electrophoretic mobility. Both palladium and platinum compounds proved active in the modification of both the secondary and tertiary DNA structures. AFM images showed noticeable modifications of the morphology of the plasmid pBR322 DNA by the
compounds probably due to the intercalation of the complexes between base pairs of the DNA molecule. Finally, the palladium complex was tested for antiproliferative activity against three different human tumor cell lines. The results suggest that the palladium complex of formula [Pd(9AA)(Ό-Cl)]2 has significant antiproliferative activity, although it is less active than cisplatin
Critical reflection in practice: Generating Knowledge from the Interactions with Promotores for Engagement in Neurocognitive Disorders
Background: Colonias are underserved areas along the Texas-Mexico border, with high incidences of neurocognitive disorders, dementia, and Alzheimer\u27s disease (AD). Our goal is to build capacity to reduce risk, facilitate treatment for affected individuals, and provide caregiver support. Our aim was to construct an approach that was reflective and would reveal the rich and diverse ways in which people make meaning of their experiences and interactions with scientists, faculty, staff and students.
Methods: We examined our work with local community health workers. (CHWs), promotores in Spanish, to establish contact with, engage, mobilize, and educate the Hispanic communities of the Lower Rio Grande Valley (LRGV). Qualitative research methods were the principal way to approach this aim, including critical reflection.
Results: We now have 347 certified promotores in LRGV: 174 in Cameron County, 169 in Hidalgo County, 3 in Starr County, and 1 in Willacy County. Most of the promotores in LRGV are female, Spanish-speakers (98%) although half of them are also fluent in English and more than half of the promotores have five years or more as a state-certified CHW. Assumptions about knowledge, power and reflexivity surfaced in the interactions with members of the academic world interacting with Coloniaâs residents.
Conclusions: Aspects of critical reflection, including deconstructing assumptions about knowledge, power and reflexivity, are useful to guide actions that facilitate capacity building in the Colonias, as well as action research methodology. The LRGV populationâs characteristics make early detection of AD and dementia and support for patients and caregiversâ high priorities and clearly understanding the role of promotores as mediators is important
Design of acoustic metamaterials made of Helmholtz resonators for perfect absorption by using the complex frequency plane
[Otros] Dans cette revue, nous présentons des résultats sur l'absorption acoustique parfaite sub-longueur
d'onde faisant appel à des métamatériaux acoustiques avec des résonateurs Helmholtz pour différentes
configurations. L'absorption parfaite à basse fréquence nécessite une augmentation du nombre d'états aux
basses fréquences ainsi que de trouver les bonnes conditions pour une adaptation d'impédance avec le milieu environnant. Si en outre, on souhaite réduire les dimensions géométriques des structures proposées pour
des questions pratiques, on peut utiliser des résonateurs locaux judicieusement conçus afin d'attendre une
absorption parfaite sub-longueur d'onde. Les résonateurs de Helmholtz se sont révélés de bons candidats en
raison de leur accordabilité aisée de la géométrie, donc de la fréquence de résonance, de la fuite d'énergie
et des pertes intrinsÚques. Lorsqu'ils sont branchés à un guide d'ondes ou à un milieu environnant, ils se
comportent comme des systÚmes ouverts, avec pertes et résonances caractérisés par leur fuite d'énergie et
leurs pertes intrinsÚques. L'équilibre entre ces deux aspects représente la condition de couplage critique et
donne lieu à un maximum d'absorption d'énergie. Le mécanisme de couplage critique est ici représenté dans
le plan de fréquence complexe afin d'interpréter la condition d'adaptation d'impédance. Dans cette revue,
nous discutons en détail la possibilité d'obtenir une absorption parfaite par ces conditions de couplage critiques dans différents systÚmes tels que la réflexion (à un port), la transmission (à deux ports) ou les systÚmes
Ă trois ports.[EN] In this review, we present the results on sub-wavelength perfect acoustic absorption using acoustic metamaterials made of Helmholtz resonators with different setups. Low frequency perfect absorption requires to increase the number of states at low frequencies and finding the good conditions for impedance
matching with the background medium. If, in addition, one wishes to reduce the geometric dimensions of
the proposed structures for practical issues, one can use properly designed local resonators and achieve subwavelength perfect absorption. Helmholtz resonators have been shown good candidates due to their easy
tunability of the geometry, so of the resonance frequency, the energy leakage and the intrinsic losses. When
plugged to a waveguide or a surrounding medium they behave as open, lossy and resonant systems characterized by their energy leakage and intrinsic losses. The balance between these two represents the critical
coupling condition and gives rise to maximum energy absorption. The critical coupling mechanism is represented here in the complex frequency plane in order to interpret the impedance matching condition. In this review we discuss in detail the possibility to obtain perfect absorption by these critical coupling conditions
in different systems such as reflection (one-port), transmission (two-ports) or three-ports systems.The authors gratefully acknowledge the ANR-RGC METARoom (ANR-18-CE08-0021) project and
the project HYPERMETA funded under the program Ătoiles Montantes of the RĂ©gion Pays de
la Loire. NJ acknowledges financial support from the Spanish Ministry of Science, Innovation and Universities (MICINN) through grant ÂżJuan de la Cierva-IncorporaciĂłnÂż (IJC2018-037897-
I). This article is based upon work from COST Action DENORMS CA15125, supported by COST
(European Cooperation in Science and Technology).Romero-GarcĂa, V.; Jimenez, N.; Theocharis, G.; Achilleos, V.; Merkel, A.; Richoux, O.; Tournat, V.... (2020). Design of acoustic metamaterials made of Helmholtz resonators for perfect absorption by using the complex frequency plane. Comptes Rendus Physique. 21(7-8):713-749. https://doi.org/10.5802/crphys.32S713749217-8[1] Law, M.; Greene, L. E.; Johnson, J. C.; Saykally, R.; Yang, P. Nanowire dye-sensitized solar cells, Nat. Mater., Volume 4 (2005) no. 6, pp. 455-459[2] Derode, A.; Roux, P.; Fink, M. Robust acoustic time reversal with high-order multiple scattering, Phys. Rev. Lett., Volume 75 (1995) no. 23, pp. 4206-4209[3] Chong, Y.; Ge, L.; Cao, H.; Stone, A. D. Coherent perfect absorbers: time-reversed lasers, Phys. Rev. Lett., Volume 105 (2010) no. 5, 053901[4] Mei, J.; Ma, G.; Yang, M.; Yang, Z.; Wen, W.; Sheng, P. Dark acoustic metamaterials as super absorbers for low-frequency sound, Nat. 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Renormalized Energies of Superfluorescent Bursts from an Electron-Hole Magneto-plasma with High Gain in InGaAs Quantum Wells
We study light emission properties of a population-inverted 2D electron-hole
plasma in a quantizing magnetic field. We observe a series of superfluorescent
bursts, discrete both in time and energy, corresponding to the cooperative
recombination of electron-hole pairs from different Landau levels. The emission
energies are strongly renormalized due to many-body interactions among the
photogenerated carriers, exhibiting red-shifts as large as 20 meV at 15 T.
However, the magnetic field dependence of the lowest Landau level emission line
remains excitonic at all magnetic fields. Interestingly, our time-resolved
measurements show that this lowest-energy burst occurs only after all upper
states become empty, suggesting that this excitonic stability is related to the
`hidden symmetry' of 2D magneto-excitons expected in the magnetic quantum
limit.Comment: 5 pages, 4 figure
LandmÊnds opfattelser af natur og aktuel naturkvalitet pÄ bedriften. Cross cutting rapport for CC3
Landmanden er en vÊsentlig aktÞr i forhold til at udvikle og forbedre natur og landskabskvaliteter pÄ de Þkologiske bedrifter. SpÞrgsmÄlet er imidlertid, om der er en sammenhÊng mellem den mÄde landmanden opfatter vÊrdier i natur og landskab pÄ, den mÄde han handler og forvalter i forhold til disse vÊrdier, og sÄ den naturkvalitet han set udfra en biologisk synsvinkel har pÄ sin bedrift. Det spÞrgsmÄl blev der arbejdet med i en cross cutting Þvelse i projektet Naturkvalitet i Þkologisk jordbrug
A novel DNA-binding motif in prostate tumor overexpressed-1 (PTOV1) required for the expression of ALDH1A1 and CCNG2 in cancer cells
PTOV1 is a transcription and translation regulator and a promoter of cancer progression. Its overexpression in prostate cancer induces transcription of drug resistance and self-renewal genes, and docetaxel resistance. Here we studied PTOV1 ability to directly activate the transcription of ALDH1A1 and CCNG2 by binding to specific promoter sequences. Chromatin immunoprecipitation and electrophoretic mobility shift assays identified a DNA-binding motif inside the PTOV-A domain with similarities to known AT-hooks that specifically interacts with ALDH1A1 and CCNG2 promoters. Mutation of this AT-hook-like sequence significantly decreased the expression of ALDH1A1 and CCNG2 promoted by PTOV1. Immunohistochemistry revealed the association of PTOV1 with mitotic chromosomes in high grade prostate, colon, bladder, and breast carcinomas. Overexpression of PTOV1, ALDH1A1, and CCNG2 significantly correlated with poor prognosis in prostate carcinomas and with shorter relapse-free survival in colon carcinoma. The previously described interaction with translation complexes and its direct binding to ALDH1A1 and CCNG2 promoters found here reveal the PTOV1 capacity to modulate the expression of critical genes at multiple levels in aggressive cancers. Remarkably, the AT-hook motifs in PTOV1 open possibilities for selective targeting its nuclear and/or cytoplasmic activities
A Local Search Algorithm for Large Maximum Weight Independent Set Problems
Motivated by a real-world vehicle routing application, we consider the maximum-weight independent set problem: Given a node-weighted graph, find a set of independent (mutually nonadjacent) nodes whose node-weight sum is maximum. Some of the graphs arising in the vehicle routing application are large, having hundreds of thousands of nodes and hundreds of millions of edges.
To solve instances of this size, we develop a new local search algorithm, which is a metaheuristic based on the greedy randomized adaptive search (GRASP) framework. This algorithm, named METAMIS, uses a wider range of simple local search operations than previously described in the literature. We introduce data structures that make these operations efficient. A new variant of path-relinking is introduced to escape local optima and so is a new alternating augmenting-path local search move that improves algorithm performance.
We compare an implementation of our algorithm with a state-of-the-art publicly available code on public benchmark sets, including some large instances. Our algorithm is, in general, competitive and outperforms this openly available code on large vehicle routing instances of the maximum weight independent set problem. We hope that our results will lead to even better maximum-weight independent set algorithms
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