7,802 research outputs found
Length-frequency estimation for yellowfin tuna (Thunnus albacares) caught by commercial fishing gear in the Eastern Pacific Ocean
ENGLISH: Methods of collecting samples for the purpose of estimating the numbers and weights of fish caught, by length interval, are described. Several models for two-stage sampling are described, and the equations for the estimators and their variances are given. The results from a brief simulation study are used to show the differences between estimates made with the different models. Estimators for the average weights of fish in the catch and their variances are also described. These average weights are used to provide improved estimates of the total annual catches of yellowfin taken from the eastern Pacific Ocean, east of 150°W, between 1955 and 1990. SPANISH: Se describen los métodos de recoger de muestreo para estimar el número o peso de peces capturados, por intervalo de talla. Se describen varios modelos para el muestreo de dos etapas, y se presentan las ecuaciones para los estimadores y sus varianzas. Se usan los resultados de un breve estudio de simulación para indicar las diferencias entre estimaciones realizadas con los distintosmodelos. También se describe un estimador para el peso promedio de peces en la captura y su varianza. Se usan estos estimadores para calcular estimaciones mejoradas de las capturas anuales totales de aleta amarilla tomadas del Océano PacÃfico oriental, al este de 150°W, entre 1955 y 1990.
(PDF contains 41 pages.
Endodontic drug delivery for root surface disinfection: a laboratory feasibility evaluation
OBJECTIVES This study aims to assess the potential of a mixture of three antibiotics (TreVitaMix, TVM) as an intracanal dressing to disinfect the outer root surface by applying a new in vitro model. MATERIALS AND METHODS Fifty freshly extracted bovine roots were endodontically treated. Forty samples were then thoroughly scaled, mounted to petri dishes, gas sterilized, and randomly allocated to four groups (n = 10/group) according to their intracanal medication: sterile saline (NaCl; control, A); the TVM carrier material alone, i.e., propylene glycol (PG; B); TVM (C); and calcium hydroxide (D). In an additional group (E), the cementum was not removed and TVM was placed. Petri dishes were filled with Fastidious Anaerobe Agar, inoculated with Fusobacterium nucleatum suspension and then anaerobically incubated during 48-h intervals at 37 °C up to 192 h. Inhibition zones around the roots were then measured after each incubation period (mm(2)). RESULTS Only teeth inoculated with the TVM dressing showed inhibition at all time points, whereas the other treatments showed no peri-radicular growing inhibition. Presence of cementum had no negative effect on disinfection (p = 0.9320). CONCLUSION TVM was able to penetrate through the dentine and inhibit the bacterial growth of F. nucleatum up to 192 h. CLINICAL RELEVANCE TVM might have the potential to sustainably disinfect the outer root surface in perio-endo lesions and serve as an adjunctive antimicrobial agent
Digging for Dark Matter: Spectral Analysis and Discovery Potential of Paleo-Detectors
Paleo-detectors are a recently proposed method for the direct detection of
Dark Matter (DM). In such detectors, one would search for the persistent damage
features left by DM--nucleus interactions in ancient minerals. Initial
sensitivity projections have shown that paleo-detectors could probe much of the
remaining Weakly Interacting Massive Particle (WIMP) parameter space. In this
paper, we improve upon the cut-and-count approach previously used to estimate
the sensitivity by performing a full spectral analysis of the background- and
DM-induced signal spectra. We consider two scenarios for the systematic errors
on the background spectra: i) systematic errors on the normalization only, and
ii) systematic errors on the shape of the backgrounds. We find that the
projected sensitivity is rather robust to imperfect knowledge of the
backgrounds. Finally, we study how well the parameters of the true WIMP model
could be reconstructed in the hypothetical case of a WIMP discovery.Comment: 14 pages, 5 figures, code available at
https://github.com/tedwards2412/paleo_detectors/ . v2: Added additional
analysis theory details, matches version published in PR
Evaluation of [99mTC(CO)3]-labeled ERBB-2-targeting peptides for breast carcinoma imaging [abstract]
The purpose of this study was to radiolabel a novel ErbB-2-avid peptide, discovered
from bacteriophage display, with [99mTc(H2 O)3 (CO)3 ]+ and evaluate the in vitro cellular targeting and in vivo tumor imaging properties of the peptide in a mouse model of human breast cancer
Facing Forward: Policy for Automated Facial Expression Analysis
The human face is a powerful tool for nonverbal communication. Technological advances have enabled widespread and low-cost deployment of video capture and facial recognition systems, opening the door for automated facial expression analysis (AFEA). This paper summarizes current challenges to the reliability of AFEA systems and challenges that could arise as a result of reliable AFEA systems. The potential benefits of AFEA are considerable, but developers, prospective users, and policy makers should proceed with caution
The Origin of Nitrogen on Jupiter and Saturn from the N/N Ratio
The Texas Echelon cross Echelle Spectrograph (TEXES), mounted on NASA's
Infrared Telescope Facility (IRTF), was used to map mid-infrared ammonia
absorption features on both Jupiter and Saturn in February 2013. Ammonia is the
principle reservoir of nitrogen on the giant planets, and the ratio of
isotopologues (N/N) can reveal insights into the molecular
carrier (e.g., as N or NH) of nitrogen to the forming protoplanets, and
hence the source reservoirs from which these worlds accreted. We targeted two
spectral intervals (900 and 960 cm) that were relatively clear of
terrestrial atmospheric contamination and contained close features of
NH and NH, allowing us to derive the ratio from a single
spectrum without ambiguity due to radiometric calibration (the primary source
of uncertainty in this study). We present the first ground-based determination
of Jupiter's N/N ratio (in the range from to
), which is consistent with both previous space-based studies
and with the primordial value of the protosolar nebula. On Saturn, we present
the first upper limit on the N/N ratio of no larger than
for the 900-cm channel and a less stringent
requirement that the ratio be no larger than for the
960-cm channel ( confidence). Specifically, the data rule out
strong N-enrichments such as those observed in Titan's atmosphere and in
cometary nitrogen compounds. To the extent possible with ground-based
radiometric uncertainties, the saturnian and jovian N/N ratios
appear indistinguishable, implying that N-enriched ammonia ices could
not have been a substantial contributor to the bulk nitrogen inventory of
either planet, favouring the accretion of primordial N from the gas phase
or as low-temperature ices.Comment: 33 pages, 19 figures, manuscript accepted for publication in Icaru
Rapid Circumstellar Disk Evolution and an Accelerating Star Formation Rate in the Infrared Dark Cloud M17 SWex
We present a catalog of 840 X-ray sources and first results from a 100 ks
Chandra X-ray Observatory imaging study of the filamentary infrared dark cloud
G014.22500.506, which forms the central regions of a larger cloud complex
known as the M17 southwest extension (M17 SWex). In addition to the rich
population of protostars and young stellar objects with dusty circumstellar
disks revealed by Spitzer Space Telescope archival data, we discover a
population of X-ray-emitting, intermediate-mass pre--main-sequence stars (IMPS)
that lack infrared excess emission from circumstellar disks. We model the
infrared spectral energy distributions of this source population to measure its
mass function and place new constraints on the inner dust disk destruction
timescales for 2-8 stars. We also place a lower limit on the star
formation rate (SFR) and find that it is quite high ( yr), equivalent to several Orion Nebula Clusters in
G14.2250.506 alone, and likely accelerating. The cloud complex has not
produced a population of massive, O-type stars commensurate with its SFR. This
absence of very massive () stars suggests that either (1)
M17 SWex is an example of a distributed mode of star formation that will
produce a large OB association dominated by intermediate-mass stars but
relatively few massive clusters, or (2) the massive cores are still in the
process of accreting sufficient mass to form massive clusters hosting O stars.Comment: 29 pages, 9 figures, accepted to Ap
Effects of Market Reform on Access to Food by Low-Income Households: Evidence from Four Countries in Eastern and Southern Africa
Food Consumption/Nutrition/Food Safety, Downloads June 2008 - June 2009: 10,
- …