996 research outputs found
A review of IATTC research on the early life history and reproductive biology of scombrids conducted at the Achotines Laboratory from 1985 to 2005
English:
For nearly a century, fisheries scientists have studied marine fish stocks in an effort to understand how the
abundances of fish populations are determined. During the early lives of marine fishes, survival is
variable, and the numbers of individuals surviving to transitional stages or recruitment are difficult to
predict.
The egg, larval, and juvenile stages of marine fishes are characterized by high rates of mortality and
growth. Most marine fishes, particularly pelagic species, are highly fecund, produce small eggs and
larvae, and feed and grow in complex aquatic ecosystems. The identification of environmental or
biological factors that are most important in controlling survival during the early life stages of marine
fishes is a potentially powerful tool in stock assessment.
Because vital rates (mortality and growth) during the early life stages of marine fishes are high and
variable, small changes in those rates can have profound effects on the properties of survivors and
recruitment potential (Houde 1989). Understanding and predicting the factors that most strongly
influence pre-recruit survival are key goals of fisheries research programs.
Spanish:
Desde hace casi un siglo, los cientĂficos pesqueros han estudiado las poblaciones de peces marinos en un
intento por entender cĂłmo se determina la abundancia de las mismas. Durante la vida temprana de los
peces marinos, la supervivencia es variable, y el nĂşmero de individuos que sobrevive hasta las etapas
transicionales o el reclutamiento es difĂcil de predecir.
Las etapas de huevo, larval, y juvenil de los peces marinos son caracterizadas por tasas altas de
mortalidad y crecimiento. La mayorĂa de los peces marinos, particularmente las especies pelágicas, son
muy fecundos, producen huevos y larvas pequeños, y se alimentan y crecen en ecosistemas acuáticos complejos. La identificación los factores ambientales o biológicos más importantes en el control de la
supervivencia durante las etapas tempranas de vida de los peces marinos es una herramienta
potencialmente potente en la evaluaciĂłn de las poblaciones.
Ya que las tasas vitales (mortalidad y crecimiento) durante las etapas tempranas de vida de los peces
marinos son altas y variables, cambios pequeños en esas tasas pueden ejercer efectos importantes sobre
las propiedades de los supervivientes y el potencial de reclutamiento (Houde 1989). Comprender y
predecir los factores que más afectan la supervivencia antes del reclutamiento son objetivos clave de los
programas de investigaciĂłn pesquera
Anomaly Cancellation in Supergravity with Fayet-Iliopoulos Couplings
We review and clarify the cancellation conditions for gauge anomalies which
occur when N=1, D=4 supergravity is coupled to a Kahler non-linear sigma-model
with gauged isometries and Fayet-Iliopoulos couplings. For a flat sigma-model
target space and vanishing Fayet-Iliopoulos couplings, consistency requires
just the conventional anomaly cancellation conditions. A consistent model with
non-vanishing Fayet-Iliopoulos couplings is unlikely unless the Green-Schwarz
mechanism is used. In this case the U(1) gauge boson becomes massive and the
D-term potential receives corrections. A Green-Schwarz mechanism can remove
both the abelian and certain non-abelian anomalies in models with a gauge
non-invariant Kahler potential.Comment: 27 page
Proteomic data on the nuclear interactome of human MCM9
AbstractWe present data relating to the interactome of MCM9 from the nuclei of human cells. MCM9 belongs to the AAA+ superfamily, and contains an MCM domain and motifs that may confer DNA helicase activity. MCM9 has been shown to bind MCM8, and has been implicated in DNA replication and homologous recombination. However, the mechanistic basis of MCM9’s role in DNA repair is poorly understood, and proteins with which it interacts were hitherto unknown. We performed tandem affinity purification of MCM9 and its interacting proteins from nuclear extracts of human cells, followed by proteomic analysis, thereby generating a set of mass spectrometry data corresponding to the MCM9 interactome [1]. The proteomic data set comprises 29 mass spectrometry RAW files, deposited to the ProteomeXchange Consortium, and freely available from the PRIDE partner repository with the data set identifier http://www.ebi.ac.uk/pride/archive/projects/PXD000212. A set of 22 interacting proteins identified from the proteomic data was used to create an MCM9-centered interactive network diagram, using the Cytoscape program. These data allow the scientific community to access, mine and explore the human nuclear MCM9 interactome
Surface Instability in Windblown Sand
We investigate the formation of ripples on the surface of windblown sand
based on the one-dimensional model of Nishimori and Ouchi [Phys. Rev. Lett. 71,
197 (1993)], which contains the processes of saltation and grain relaxation. We
carry out a nonlinear analysis to determine the propagation speed of the
restabilized ripple patterns, and the amplitudes and phases of their first,
second, and third harmonics. The agreement between the theory and our numerical
simulations is excellent near the onset of instability. We also determine the
Eckhaus boundary, outside which the steady ripple patterns are unstable.Comment: 23 pages, 8 figure
Recommended from our members
Review of Immunotherapy Classification: Application Domains, Datasets, Algorithms and Software Tools from Machine Learning Perspective
YesImmunotherapy treatments can be essential sometimes and a waste of valuable resources in other cases, depending on the diagnosis results. Therefore, researchers in
immunotherapy need to be updated on the current status of
research by exploring: application domains e.g. warts, datasets
e.g. immunotherapy, classifiers or algorithms e.g. kNN and
software tools. The research objectives were: 1) to study the
immunotherapy-related published literature from a supervised
machine learning perspective. In addition, to reproduce immunotherapy classifiers reported in research papers. 2) To find
gaps and challenges both in publications and practical work,
which may be the basis for further research. Immunotherapy,
diabetes, cryotherapy, exasens data and ”one unbalanced dataset”
are explored. The results are compared with published literature.
To address the found gaps in further research: novel experiments,
unbalanced studies, focus on effectiveness and a new classifier
algorithm are suggested
Plaque formation by bluetongue virus
The formation of plaques in a line of mouse fibroblast cells under agarose, by 16 tissue culture and 14 egg adapted strains of bluetongue virus is described. Optimal conditions for routine plaque assay were determined and certain basic requirements substantiated. The technique was used to determine the thermal stability of the virus under various conditions and in selected biological stabilizers.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format
Spin Reduction Transition in Spin-3/2 Random Heisenberg Chains
Random spin-3/2 antiferromagnetic Heisenberg chains are investigated using an
asymptotically exact renormalization group. Randomness is found to induce a
quantum phase transition between two random-singlet phases. In the strong
randomness phase the effective spins at low energies are S_eff=3/2, while in
the weak randomness phase the effective spins are S_eff=1/2. Separating them is
a quantum critical point near which there is a non-trivial mixture of S=1/2,
S=1, and S=3/2 effective spins at low temperatures.Comment: 4 pages, 3 figures. Typos correcte
Some FRW Models of Accelerating Universe with Dark Energy
The paper deals with a spatially homogeneous and isotropic FRW space-time
filled with perfect fluid and dark energy components. The two sources are
assumed to interact minimally, and therefore their energy momentum tensors are
conserved separately. A special law of variation for the Hubble parameter
proposed by Berman (1983) has been utilized to solve the field equations. The
Berman's law yields two explicit forms of the scale factor governing the FRW
space-time and constant values of deceleration parameter. The role of dark
energy with variable equation of state parameter has been studied in detail in
the evolution of FRW universe. It has been found that dark energy dominates the
universe at the present epoch, which is consistent with the observations. The
physical behavior of the universe is discussed in detail.Comment: 10 pages, 5 figure
Active facilitation of focus groups: exploring the implementation of inclusive education with research participants
In this article, we explain how we took an “active” approach to focus group discussions with
teachers in three South African schools. The topic of discussion was their views on the
implementation of inclusive education. We shall also show how we sought feedback from the
participants on their experiences of these discussions. In seeking this feedback, we were
interested in seeing if they interpreted the sessions as being learning experiences – that is, as
sessions that enabled the participants to learn from each other as well as from facilitators with
a view to promoting mutual learning. We indicate how the participants chose to use the feedback
opportunity to suggest that further processes should be put in place (by us) in the light of
their expressed concerns. Finally, we outline how we took responsibility by creating a further
forum for discussion with those who were regarded as having additional “actioning” power.ABET and Youth Developmen
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