1,574 research outputs found
Growth rates and survival of western rock lobster (Panulirus cygnus) at twotemperatures (ambient and 23 C) and two feeding frequencies
Wild caught post-pueruli, year one and year two post settlement juvenile western rock lobster, Panuliruscygnus, were held at ambient temperatures (15.6 C to 23.1 C; mean 19.00.07 C) or at 23 C, and fed thesame ration of a formulated pellet diet either once per night, or 3 times per night, over 12 months, todetermine whether elevated temperatures and multiple feeds per night would stimulate growth throughincreased metabolism and feed utilisation without significant negative impacts on survival. Survival of postpueruli(mean 63%) did not differ between ambient and 23 C. Survival of year 1 and 2 juveniles was higher atambient temperatures (pb0.01 ambient: year 1 juveniles, 68%; year 2 juveniles, 88%; 23 C: 57% and 74%,respectively). Feeding frequency did not affect survival of post-pueruli and year 2 juveniles (mean 63%, 81%respectively), but survival was 9% higher for year 1 juveniles fed three times per night (58% versus 67%;pb0.01). All lobsters grew faster at 23 C than at ambient temperatures (pb0.05), with the growth ofpost-pueruli almost doubled at 23 C (weight gain at 23 C versus ambient: post-pueruli, 18 438 % versus 9915 %; year 1 juveniles 259% versus 165%; year 2 juveniles 23% versus 21%). Feed frequency did not influencethe growth of year 1 and 2 juveniles. However, there was an interaction effect of temperature and feedfrequency on post-pueruli where weight and carapace length were significantly higher at ambienttemperatures when post-pueruli were fed three times a day, whereas at 23 C weight and carapace lengthwere significantly greater when fed once per day (pb0.05). Feed intake (g pellet dry matter lobster-1 day-1)of pellet was higher at 23 C for all lobsters (pb0.05), but was the same between lobsters fed 3 times pernight versus once per night. This study has shown that increasing temperatures to 23 C significantlyimproved the growth of P. cygnus post-pueruli without any adverse effects on survival. The faster growthrates exhibited by year 1 and 2 juveniles at 23 C may potentially offset their lower survival by significantlyreducing culture period. There is no benefit of feeding P. cygnus multiple times at night in terms of growthand survival. The implications for P. cygnus culture are that temperatures should be maintained close to 23 Cduring the entire growout period, with due care taken to minimise mortalities through adequate provision offood and shelter. Feeding P. cygnus once daily to excess just prior to dusk to co-incide with nocturnal feedingbehaviour is recommended
Perspectives for implementing fisheries certification in developing countries
This paper discusses the future of the Marine Stewardship Council (MSC), a market-based certification program, in developing countries and exposes the challenges and opportunities for fish producers. The MSC needs to attract the interest of more fishing enterprises from these regions to increase its global presence. Because most fisheries in developing countries cannot meet the MSC standards, or afford the certification process costs, it is suggested that there is a need for developing different levels within the MSC system and additional third-party assessing organizations. MSC certification may mean adoption of improvements in fisheries management and approving fishing regimes in developing countries. However, post-certification benefits may decrease as more fisheries become certified
Stocking density and shelter type for the optimal growth and survival of western rock lobster Panulirus cygnus (George)
The growth and survival of three size classes of wild caught western rock lobster, Panulirus cygnus (post-pueruli: mean 2.140.07g, 13.20.1mm CL; year1: post-settlement juveniles, 57.11.1g, 38.70.28mm CL; and year2 post-settlement juveniles, mean 138.22.26g, 51.90.25mm CL) were examined at combinations of two stocking densities (post-pueruli: 50 and 100myear1: 11 and 23m2; year2: 10 and 19m2) and two shelter types (a novel rigid plastic mesh shelter or bricks) over a period 6months. Survival of lobsters held at the lower densities (90 95%) was significantly greater than for lobsters held at higher densities (post-pueruli=78%, year1=86%, year2=88%). Post-pueruli survival was significantly higher in tanks with mesh shelters (91.7%) than brick shelters (75.8%) with a similar trend exhibited by year1 and year2 lobsters. Densities tested did significantly affect lobster growth for any size class. Growth of post-pueruli was considerably higher in tanks with mesh shelters (641.7% weight gain; specific growth rate 1.07BWday1) (p<0.05) but there was no difference in the growth of year1 and lobsters between mesh and brick shelters. Feed intake (g pellet dry matter lobster1day1) was not significantly different between densities. This study has shown that P. cygnus is well suited for aquaculture based on the collection and ongrowing of wild caught pueruli, as this species exhibits good survival at high densities (up to 100m2) without adverse effects on growth, and shows captivity-related health problems. We recommend mesh shelters, with stocking densities of 50m2 for post-pueruli and between and 25m2 for year1 and year2 juveniles, to maximise survival and production
Evaluating quality of life tools in North American patients with erythropoietic protoporphyria and X-linked protoporphyria.
BackgroundErythropoietic protoporphyria (EPP) and X-linked Protoporphyria (XLP) are rare photodermatoses presenting with severe phototoxicity. Although anecdotally, providers who treat EPP patients acknowledge their life-altering effects, tools that fully capture their impact on quality of life (QoL) are lacking.MethodsAdult patients with EPP/XLP were given four validated QoL tools: the Patient Reported Outcomes Measurement Information System 57 (PROMIS-57), the Hospital Anxiety and Depression Scale (HADS), the Illness Perception Questionnaire Revised (IPQR), and an EPP-Specific tool. All patients received the PROMIS-57 while the HADS, IPQR, and EPP-Specific tools were introduced at a later date. Associations between responses and clinical phenotypes were explored.ResultsTwo hundred and two patients were included; 193 completed PROMIS-57, 104 completed IPQR, 103 completed HADS, and 107 completed the EPP-Specific tool. The IPQR showed that patients strongly believed EPP/XLP had a negative impact on their lives. Mean scores in anxiety and depression domains of both HADS and PROMIS-57 were normal; however, anxiety scores from HADS were borderline/abnormal in 20% of patients. The EPP-Specific tool revealed a decreased QoL in most patients. The PROMIS-57 showed that 21.8% of patients have clinically significant pain interference. Several tool domains correlated with measures of disease severity, most being from the PROMIS-57.ConclusionsImpaired QoL is an important consequence of EPP/XLP. PROMIS-57 was most sensitive in evaluating impaired QoL in EPP/XLP. Further research is needed to compare the effectiveness of it for assessing response to treatment
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Evaluating the Patient-Reported Outcomes Measurement Information System scales in acute intermittent porphyria.
PurposeAcute intermittent porphyria (AIP) is a rare inborn error of heme biosynthesis characterized by life-threatening acute attacks. Few studies have assessed quality of life (QoL) in AIP and those that have had small sample sizes and used tools that may not have captured important domains.MethodsBaseline data from the Porphyrias Consortium's Longitudinal Study were obtained for 259 patients, including detailed disease and medical history data, and the following Patient-Reported Outcomes Measurement Information System (PROMIS) scales: anxiety, depression, pain interference, fatigue, sleep disturbance, physical function, and satisfaction with social roles. Relationships between PROMIS scores and clinical and biochemical AIP features were explored.ResultsPROMIS scores were significantly worse than the general population across all domains, except depression. Each domain discriminated well between asymptomatic and symptomatic patients with symptomatic patients having worse scores. Many important clinical variables like symptom frequency were significantly associated with domain scores in univariate analyses, showing responsiveness of the scales, specifically pain interference and fatigue. However, most regression models only explained ~20% of the variability observed in domain scores.ConclusionPain interference and fatigue were the most responsive scales in measuring QoL in this AIP cohort. Future studies should assess whether these scales capture longitudinal disease progression and treatment response
Tolerating the Community Detection Resolution Limit with Edge Weighting
Communities of vertices within a giant network such as the World-Wide Web are
likely to be vastly smaller than the network itself. However, Fortunato and
Barth\'{e}lemy have proved that modularity maximization algorithms for
community detection may fail to resolve communities with fewer than
edges, where is the number of edges in the entire network.
This resolution limit leads modularity maximization algorithms to have
notoriously poor accuracy on many real networks. Fortunato and Barth\'{e}lemy's
argument can be extended to networks with weighted edges as well, and we derive
this corollary argument. We conclude that weighted modularity algorithms may
fail to resolve communities with fewer than total edge
weight, where is the total edge weight in the network and is the
maximum weight of an inter-community edge. If is small, then small
communities can be resolved.
Given a weighted or unweighted network, we describe how to derive new edge
weights in order to achieve a low , we modify the ``CNM'' community
detection algorithm to maximize weighted modularity, and show that the
resulting algorithm has greatly improved accuracy. In experiments with an
emerging community standard benchmark, we find that our simple CNM variant is
competitive with the most accurate community detection methods yet proposed.Comment: revision with 8 pages 3 figures 2 table
The Carnegie Supernova Project: First Near-Infrared Hubble Diagram to z~0.7
The Carnegie Supernova Project (CSP) is designed to measure the luminosity
distance for Type Ia supernovae (SNe Ia) as a function of redshift, and to set
observational constraints on the dark energy contribution to the total energy
content of the Universe. The CSP differs from other projects to date in its
goal of providing an I-band {rest-frame} Hubble diagram. Here we present the
first results from near-infrared (NIR) observations obtained using the Magellan
Baade telescope for SNe Ia with 0.1 < z < 0.7. We combine these results with
those from the low-redshift CSP at z <0.1 (Folatelli et al. 2009). We present
light curves and an I-band Hubble diagram for this first sample of 35 SNe Ia
and we compare these data to 21 new SNe Ia at low redshift. These data support
the conclusion that the expansion of the Universe is accelerating. When
combined with independent results from baryon acoustic oscillations (Eisenstein
et al. 2005), these data yield Omega_m = 0.27 +/- 0.0 (statistical), and
Omega_DE = 0.76 +/- 0.13 (statistical) +/- 0.09 (systematic), for the matter
and dark energy densities, respectively. If we parameterize the data in terms
of an equation of state, w, assume a flat geometry, and combine with baryon
acoustic oscillations, we find that w = -1.05 +/- 0.13 (statistical) +/- 0.09
(systematic). The largest source of systematic uncertainty on w arises from
uncertainties in the photometric calibration, signaling the importance of
securing more accurate photometric calibrations for future supernova cosmology
programs. Finally, we conclude that either the dust affecting the luminosities
of SNe Ia has a different extinction law (R_V = 1.8) than that in the Milky Way
(where R_V = 3.1), or that there is an additional intrinsic color term with
luminosity for SNe Ia independent of the decline rate.Comment: 44 pages, 23 figures, 9 tables; Accepted for publication in the
Astrophysical Journa
A novel isolator-based system promotes viability of human embryos during laboratory processing
In vitro fertilisation (IVF) and related technologies are arguably the most challenging of all cell culture applications. The starting material is a single cell from which one aims to produce an embryo capable of establishing a pregnancy eventually leading to a live birth. Laboratory processing during IVF treatment requires open manipulations of gametes and embryos, which typically involves exposure to ambient conditions. To reduce the risk of cellular stress, we have developed a totally enclosed system of interlinked isolator-based workstations designed to maintain oocytes and embryos in a physiological environment throughout the IVF process. Comparison of clinical and laboratory data before and after the introduction of the new system revealed that significantly more embryos developed to the blastocyst stage in the enclosed isolator-based system compared with conventional open-fronted laminar flow hoods. Moreover, blastocysts produced in the isolator-based system contained significantly more cells and their development was accelerated. Consistent with this, the introduction of the enclosed system was accompanied by a significant increase in the clinical pregnancy rate and in the proportion of embryos implanting following transfer to the uterus. The data indicate that protection from ambient conditions promotes improved development of human embryos. Importantly, we found that it was entirely feasible to conduct all IVF-related procedures in the isolator-based workstations
The Early Optical Afterglow of GRB 030418 and Progenitor Mass Loss
The ROTSE-IIIa telescope and the SSO 40 inch (1.0 m) telescope, both located at Siding Spring Observatory, imaged the early-time afterglow of GRB 030418. In this report, we present observations of the early afterglow, first detected by the ROTSE-IIIa telescope 211 s after the start of the burst and only 76 s after the end of the gamma-ray activity. We detect optical emission that rises for ∼600 s, slowly varies around R = 17.3 mag for ∼1400 s, and then fades as a power law of index α = -1.36. Additionally, the ROTSE-IIIb telescope, located at McDonald Observatory, imaged the early-time afterglow of GRB 030723. The behavior of this light curve was qualitatively similar to that of GRB 030418, but 2 mag dimmer. These two afterglows are dissimilar to other afterglows such as GRB 990123 and GRB 021211. We investigate whether or not the early afterglow can be attributed to a synchrotron break in a cooling synchrotron spectrum as it passes through the optical band, but we find that this model is unable to accurately describe the early light curve. We present a simple model for gamma-ray burst emission emerging from a wind medium surrounding a massive progenitor star. This model provides an effective description of the data and suggests that the rise of the afterglow can be ascribed to extinction in the local circumburst environment. In this interpretation, these events provide further evidence of the connection between gamma-ray bursts and the collapse of massive stars.This work has been supported by NASA grants NAG5-
5281 and F006794, NSF grants AST 01-19685 and 01-05221,
the Australian Research Council, the University of New South
Wales, and the University of Michigan. Work performed at
LANL is supported by NASA SR&T through Department of
Energy (DOE) contract W-7405-ENG-36 and through internal
LDRD funding
Production of membrane proteins for characterisation of their pheromone-sensing and antimicrobial resistance functions
AbstractDespite the importance of membrane proteins in cellular processes, studies of these hydrophobic proteins present major technical challenges, including expression and purification for structural and biophysical studies. A modified strategy of that proposed previously by Saidijam et al. (2005) and others, for the routine expression of bacterial membrane proteins involved in environmental sensing and antimicrobial resistance (AMR), is proposed which results in purification of sufficient proteins for biophysical experiments. We report expression successes amongst a collection of enterococcal vancomycin resistance membrane proteins: VanTG, VanTG-M transporter domain, VanZ and the previously characterised VanS (A-type) histidine protein kinase (HPK). Using the same strategy, we report on the successful amplification and purification of intact BlpH and ComD2 HPKs of Streptococcus pneumoniae. Near-UV circular dichroism revealed both recombinant proteins bound their pheromone ligands BlpC and CSP2. Interestingly, CSP1 also interacted with ComD. Finally, we evaluate the alternative strategy for studying sensory HPKs involving isolated soluble sensory domain fragments, exemplified by successful production of VicKESD of Enterococcus faecalis VicK. Purified VicKESD possessed secondary structure post-purification. Thermal denaturation experiments using far-UV CD, a technique which can be revealing regarding ligand binding, revealed that: (a) VicKESD denaturation occurs between 15 and 50 °C; and (b) reducing conditions did not detectably affect denaturation profiles suggesting reducing conditions per se are not directly sensed by VicKESD. Our findings provide information on a modified strategy for the successful expression, production and/or storage of bacterial membrane HPKs, AMR proteins and sensory domains for their future crystallisation, and ligand binding studies
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