2,730 research outputs found
Present Knowledge of the Systematics and Zoogeography of the Order Gorgonacea in Hawaii
Past knowledge of the order Gorgonacea in Hawaii is based almost
exclusively on the collections of the United States Fish Commission steamer Albatross
in 1902, which contain 52 species. Recent efforts to investigate the ecology of
precious coral have produced a new collection based on 183 dredge hauls and 10
dives with a submersible. This program is collectively referred to as the Sango
Expedition. Of 59 species of gorgonians obtained by the Sango Expedition, 13 are
considered to be new species and 28 new geographic records, bringing the total
number of species considered to be present in Hawaii to 93 species.
In contrast to the high diversity of gorgonians in the West Indies and the Indo-West-Pacific, the faunal list in Hawaii must still be considered depauperate. This is
especially true in shallow water <75 m), where only one species is known. Although climatic deterioration during the Pleistocene could account for the scarcity
of gorgonians in shallow water at the present time, this factor is unlikely to have
affected deeper species. Furthermore, one would expect to find a modern complement
of an ancestral faun a in shallow water if it had existed, as is true in the case of
reef corals. The paucity of gorgonians in Hawaii may be due to isolation, which
appears to have been a particularly effective barrier in shallow water. It is suggested
that the only accessible route to Hawaii for gorgonians has been in deep water
where, in the past, there were numerous stepping stones that may have aided dispersal.
Moreover, chemical and physical gradients in deep water are relatively low.
Why more deepwater species have not migrated into shallow water in Hawaii may
be a reflection of their stenotypic character
Evaluating Midwifery Units (EMU): A prospective cohort study of freestanding midwifery units in New South Wales, Australia
© 2014, BMJ Publishing Group. All rights reserved. Objective: To compare maternal and neonatal birth outcomes and morbidities associated with the intention to give birth in two freestanding midwifery units and two tertiary-level maternity units in New South Wales, Australia. Design: Prospective cohort study. Participants: 494 women who intended to give birth at freestanding midwifery units and 3157 women who intended to give birth at tertiary-level maternity units. Participants had low risk, singleton pregnancies and were at less than 28+0 weeks gestation at the time of booking. Primary and secondary outcome measures: Primary outcomes were mode of birth, Apgar score of less than 7 at 5 min and admission to the neonatal intensive care unit or special care nursery. Secondary outcomes were onset of labour, analgesia, blood loss, management of third stage of labour, perineal trauma, transfer, neonatal resuscitation, breastfeeding, gestational age at birth, birth weight, severe morbidity and mortality. Results: Women who planned to give birth at a freestanding midwifery unit were significantly more likely to have a spontaneous vaginal birth (AOR 1.57; 95% CI 1.20 to 2.06) and significantly less likely to have a caesarean section (AOR 0.65; 95% CI 0.48 to 0.88). There was no significant difference in the AOR of 5 min Apgar scores, however, babies from the freestanding midwifery unit group were significantly less likely to be admitted to neonatal intensive care or special care nursery (AOR 0.60; 95% CI 0.39 to 0.91). Analysis of secondary outcomes indicated that planning to give birth in a freestanding midwifery unit was associated with similar or reduced odds of intrapartum interventions and similar or improved odds of indicators of neonatal well-being. Conclusions: The results of this study support the provision of care in freestanding midwifery units as an alternative to tertiary-level maternity units for women with low risk pregnancies at the time of booking
Standardization of highway construction delay claim analysis: A highway bridge case study
Highway construction efficiency is critical to highway users such as the trucking industry given today’s era of shortages in funding, and given the need for major re-investments in the highway system. One topic that can add to project costs relates to delays and how contractors are reimbursed for such delays. Delays are common in construction, especially in complex heavy highway and other infrastructure projects, and the claims they generate have negative effects on project schedules and costs. In spite of this, the analysis of claims is hindered due to the variety of methods and analysis techniques in use and lack of standardization in the incorporation of delay claim analysis methods in construction contracts. This paper reviews different methods for delay claim analysis and outlines their advantages and disadvantages. A case study of a bridge project is used to demonstrate the potential for manipulation by using different methods for the same delay case. The analysis shows clearly that a standardized process for delay claim analysis would improve highway construction contracting. Research needs to create a standardized process are outlined
Recommended from our members
Factors influencing utilisation of ‘free-standing’ and ‘alongside’ midwifery units for low-risk births in England: a mixed-methods study
Background
Midwifery-led units (MUs) are recommended for ‘low-risk’ births by the National Institute for Health and Care Excellence but according to the National Audit Office were not available in one-quarter of trusts in England in 2013 and, when available, were used by only a minority of the low-risk women for whom they should be suitable. This study explores why.
Objectives
To map the provision of MUs in England and explore barriers to and facilitators of their development and use; and to ascertain stakeholder views of interventions to address these barriers and facilitators.
Design
Mixed methods – first, MU access and utilisation across England was mapped; second, local media coverage of the closure of free-standing midwifery units (FMUs) were analysed; third, case studies were undertaken in six sites to explore the barriers and facilitators that have an impact on the development of MUs; and, fourth, by convening a stakeholder workshop, interventions to address the barriers and facilitators were discussed.
Setting
English NHS maternity services.
Participants
All trusts with maternity services.
Interventions
Establishing MUs.
Main outcome measures
Numbers and types of MUs and utilisation of MUs.
Results
Births in MUs across England have nearly tripled since 2011, to 15% of all births. However, this increase has occurred almost exclusively in alongside units, numbers of which have doubled. Births in FMUs have stayed the same and these units are more susceptible to closure. One-quarter of trusts in England have no MUs; in those that do, nearly all MUs are underutilised. The study findings indicate that most trust managers, senior midwifery managers and obstetricians do not regard their MU provision as being as important as their obstetric-led unit provision and therefore it does not get embedded as an equal and parallel component in the trust’s overall maternity package of care. The analysis illuminates how provision and utilisation are influenced by a complex range of factors, including the medicalisation of childbirth, financial constraints and institutional norms protecting the status quo.
Limitations
When undertaking the case studies, we were unable to achieve representativeness across social class in the women’s focus groups and struggled to recruit finance directors for individual interviews. This may affect the transferability of our findings.
Conclusions
Although there has been an increase in the numbers and utilisation of MUs since 2011, significant obstacles remain to MUs reaching their full potential, especially FMUs. This includes the capacity and willingness of providers to address women’s information needs. If these remain unaddressed at commissioner and provider level, childbearing women’s access to MUs will continue to be restricted.
Future work
Work is needed on optimum approaches to improve decision-makers’ understanding and use of clinical and economic evidence in service design. Increasing women’s access to information about MUs requires further studies of professionals’ understanding and communication of evidence. The role of FMUs in the context of rural populations needs further evaluation to take into account user and community impact.
Funding
This project was funded by the National Institute for Health Research (NIHR) Health Services and Delivery Research programme and will be published in full in Health Services and Delivery Research; Vol. 8, No. 12. See the NIHR Journals Library website for further project information
Allosteric Control Of Oxygen Binding By Haemoglobin During Embryonic Development In The Crocodile Crocodylus porosus: The Role Of Red Cell Organic Phosphates And Carbon Dioxide
The P50 of whole blood [30 degrees C, PCO2=2.08 kPa (15.6 mmHg)] decreases during embryonic development from approximately 6.7 kPa (50 mmHg) at 15 days to about half this value at hatching (86 days), paralleling a decrease in ATP from 100 to 5-10 micromole g-1 Hb. There is also a progressive changeover from embryonic to adult haemoglobin (HbA). A pulse of 2,3- diphosphoglycerate (2,3-DPG) (18 micromole g-1 Hb) occurs late in embryonic life. It has no effect on whole-blood oxygen-affinity and falls rapidly at hatching to values typical of post-hatchling crocodilians in general
Recommended from our members
Factors influencing the utilisation of free-standing and alongside midwifery units in England: a qualitative research study
OBJECTIVE: To identify factors influencing the provision, utilisation and sustainability of midwifery units (MUs) in England.
DESIGN: Case studies, using individual interviews and focus groups, in six National Health Service (NHS) Trust maternity services in England.
SETTING AND PARTICIPANTS: NHS maternity services in different geographical areas of England Maternity care staff and service users from six NHS Trusts: two Trusts where more than 20% of all women gave birth in MUs, two Trusts where less than 10% of all women gave birth in MUs and two Trusts without MUs. Obstetric, midwifery and neonatal clinical leaders, managers, service user representatives and commissioners were individually interviewed (n=57). Twenty-six focus groups were undertaken with midwives (n=60) and service users (n=52).
MAIN OUTCOME MEASURES: Factors influencing MU use.
FINDINGS: The study findings identify several barriers to the uptake of MUs. Within a context of a history of obstetric-led provision and lack of decision-maker awareness of the clinical and economic evidence, most Trust managers and clinicians do not regard their MU provision as being as important as their obstetric unit (OU) provision. Therefore, it does not get embedded as an equal and parallel component in the Trust's overall maternity package of care. The analysis illuminates how implementation of complex interventions in health services is influenced by a range of factors including the medicalisation of childbirth, perceived financial constraints, adequate leadership and institutional norms protecting the status quo.
CONCLUSIONS: There are significant obstacles to MUs reaching their full potential, especially free-standing midwifery units. These include the lack of commitment by providers to embed MUs as an essential service provision alongside their OUs, an absence of leadership to drive through these changes and the capacity and willingness of providers to address women's information needs. If these remain unaddressed, childbearing women's access to MUs will continue to be restricted
Gene expression in Leishmania is regulated predominantly by gene dosage
ABSTRACT Leishmania tropica, a unicellular eukaryotic parasite present in North and East Africa, the Middle East, and the Indian subcontinent, has been linked to large outbreaks of cutaneous leishmaniasis in displaced populations in Iraq, Jordan, and Syria. Here, we report the genome sequence of this pathogen and 7,863 identified protein-coding genes, and we show that the majority of clinical isolates possess high levels of allelic diversity, genetic admixture, heterozygosity, and extensive aneuploidy. By utilizing paired genome-wide high-throughput DNA sequencing (DNA-seq) with RNA-seq, we found that gene dosage, at the level of individual genes or chromosomal “somy” (a general term covering disomy, trisomy, tetrasomy, etc.), accounted for greater than 85% of total gene expression variation in genes with a 2-fold or greater change in expression. High gene copy number variation (CNV) among membrane-bound transporters, a class of proteins previously implicated in drug resistance, was found for the most highly differentially expressed genes. Our results suggest that gene dosage is an adaptive trait that confers phenotypic plasticity among natural Leishmania populations by rapid down- or upregulation of transporter proteins to limit the effects of environmental stresses, such as drug selection. IMPORTANCE Leishmania is a genus of unicellular eukaryotic parasites that is responsible for a spectrum of human diseases that range from cutaneous leishmaniasis (CL) and mucocutaneous leishmaniasis (MCL) to life-threatening visceral leishmaniasis (VL). Developmental and strain-specific gene expression is largely thought to be due to mRNA message stability or posttranscriptional regulatory networks for this species, whose genome is organized into polycistronic gene clusters in the absence of promoter-mediated regulation of transcription initiation of nuclear genes. Genetic hybridization has been demonstrated to yield dramatic structural genomic variation, but whether such changes in gene dosage impact gene expression has not been formally investigated. Here we show that the predominant mechanism determining transcript abundance differences (>85%) in Leishmania tropica is that of gene dosage at the level of individual genes or chromosomal somy
Whole genome sequencing of experimental hybrids supports meiosis-like sexual recombination in Leishmania
Hybrid genotypes have been repeatedly described among natural isolates of Leishmania, and the recovery of experimental hybrids from sand flies co-infected with different strains or species of Leishmania has formally demonstrated that members of the genus possess the machinery for genetic exchange. As neither gamete stages nor cell fusion events have been directly observed during parasite development in the vector, we have relied on a classical genetic analysis to determine if Leishmania has a true sexual cycle. Here, we used whole genome sequencing to follow the chromosomal inheritance patterns of experimental hybrids generated within and between different strains of L. major and L. infantum. We also generated and sequenced the first experimental hybrids in L. tropica. We found that in each case the parental somy and allele contributions matched the inheritance patterns expected under meiosis 97–99% of the time. The hybrids were equivalent to F1 progeny, heterozygous throughout most of the genome for the markers that were homozygous and different between the parents. Rare, non-Mendelian patterns of chromosomal inheritance were observed, including a gain or loss of somy, and loss of heterozygosity, that likely arose during meiosis or during mitotic divisions of the progeny clones in the fly or culture. While the interspecies hybrids appeared to be sterile, the intraspecies hybrids were able to produce backcross and outcross progeny. Analysis of 5 backcross and outcross progeny clones generated from an L. major F1 hybrid, as well as 17 progeny clones generated from backcrosses involving a natural hybrid of L. tropica, revealed genome wide patterns of recombination, demonstrating that classical crossing over occurs at meiosis, and allowed us to construct the first physical and genetic maps in Leishmania. Altogether, the findings provide strong evidence for meiosis-like sexual recombination in Leishmania, presenting clear opportunities for forward genetic analysis and positional cloning of important genes.</div
Diversity of Zoanthids (Anthozoa: Hexacorallia) on Hawaiian Seamounts: Description of the Hawaiian Gold Coral and Additional Zoanthids
The Hawaiian gold coral has a history of exploitation from the deep slopes and seamounts of the Hawaiian Islands as one of the precious corals commercialised in the jewellery industry. Due to its peculiar characteristic of building a scleroproteic skeleton, this zoanthid has been referred as Gerardia sp. (a junior synonym of Savalia Nardo, 1844) but never formally described or examined by taxonomists despite its commercial interest. While collection of Hawaiian gold coral is now regulated, globally seamounts habitats are increasingly threatened by a variety of anthropogenic impacts. However, impact assessment studies and conservation measures cannot be taken without consistent knowledge of the biodiversity of such environments. Recently, multiple samples of octocoral-associated zoanthids were collected from the deep slopes of the islands and seamounts of the Hawaiian Archipelago. The molecular and morphological examination of these zoanthids revealed the presence of at least five different species including the gold coral. Among these only the gold coral appeared to create its own skeleton, two other species are simply using the octocoral as substrate, and the situation is not clear for the final two species. Phylogenetically, all these species appear related to zoanthids of the genus Savalia as well as to the octocoral-associated zoanthid Corallizoanthus tsukaharai, suggesting a common ancestor to all octocoral-associated zoanthids. The diversity of zoanthids described or observed during this study is comparable to levels of diversity found in shallow water tropical coral reefs. Such unexpected species diversity is symptomatic of the lack of biological exploration and taxonomic studies of the diversity of seamount hexacorals
- …