363 research outputs found
Growth of foliose lichens: a review
This review considers various aspects of the growth of foliose lichens including early growth and development, variation in radial growth rate (RaGR) of different species, growth to maturity, lobe growth variation, senescence and fragmentation, growth models, the influence of environmental variables, and the maintenance of thallus symmetry. The data suggest that a foliose lichen thallus is essentially a ‘colony’ in which the individual lobes exhibit a considerable degree of autonomy in their growth processes. During development, recognisable juvenile thalli are usually formed by 15 months to 4 years while most mature thalli exhibit RaGR between 1 and 5 mm yr-1. RaGR within a species is highly variable. The growth rate-size curve of a foliose lichen thallus may result from growth processes that take place at the tips of individual lobes together with size-related changes in the intensity of competition for space between the marginal lobes. Radial growth and growth in mass is influenced by climatic and microclimatic factors and also by substratum factors such as rock and bark texture, chemistry, and nutrient enrichment. Possible future research topics include: (1) measuring fast growing foliose species through life, (2) the three dimensional changes that occur during lobe growth, (3) the cellular changes that occur during regeneration, growth, and division of lobes, and (4) the distribution and allocation of the major lichen carbohydrates within lobes
Deglacial landform assemblage records fast ice-flow and retreat, Inner Hebrides, Scotland
High-resolution bathymetric data have been central to recent advances in the understanding of past dynamics of the former British–Irish Ice Sheet (BIIS). As approximately two-thirds of the former BIIS was probably marine-based during the Last Glacial Maximum (LGM) (c. 29–23 ka), geomorphic observations of the seabed are required increasingly to understand the extent, pattern and timing of past glaciation. Until recently, glacial reconstructions for the Inner Hebrides, offshore of western Scotland, have been based primarily on terrestrial observations. Previous workers have proposed generalized reconstructions in which the Inner Hebrides are located within a significant former ice-sheet flow pathway that drained the western Scottish sector of the BIIS, feeding the Barra Fan during the LGM and earlier glaciations (Fig. 1). Results from numerical ice-sheet modelling suggest that former ice-flow velocities within the region were on the order of hundreds to thousands of metres per year, but yield further insight by demonstrating how dynamic binge/purge cycles may have affected ice-sheet mass balance over time (Hubbard et al. 2009). Following the LGM, ice-sheet retreat through the area is estimated to have been in the order of 20 m per year (Clark et al. 2012). Here we present swath-bathymetric data from the Inner Hebrides that provide in situ constraints on ice-sheet flow and subsequent retreat dynamics from within this important sector of the BIIS
Stressors, Self-Esteem, Social Activities, and Depression: A Sample of Patients at a Federally Qualified Health Center Who Experienced Homelessness
This study examined the relationships between current stressors and depressive symptoms among Federally Qualified Health Center (FQHC) patients who experienced homelessness, with a particular focus on the role of self-esteem and social activities on these relationships. The sample included patients who visited any clinic site of a FQHC in the southern part of Mississippi and qualified for the Health Care for the Homeless (HCH) Program. Assessments included the Patient Health Questionnaire (PHQ-9), the DUKE Health Profile, and a checklist of stressors. Results of the multivariate analysis using structural equation modeling revealed that ambulation difficulties were related to depressive symptoms directly and indirectly through social activities. SES-related stressors were related to depressive symptoms directly and indirectly through self-esteem and social activities. Relational and legal/police-related stressors were linked to depressive symptoms only through self-esteem. These results indicate the importance of integrated community healthcare services to address the physical, social, and mental healthcare needs of the homeless population
The geomorphology of Svínafellsjökull and Virkisjökull-Falljökull glacier forelands, southeast Iceland
A detailed, 1:10,500-scale, surficial geology and glacial geomorphology map of Svínafellsjökull and Virkisjökull-Falljökull glacier forelands in southeast Iceland depicts the landsystem imprint of Holocene glacier fluctuations, volcanogenic outburst floods and recent (post-1990) climate-induced rapid ice-front retreat. The map is based on field survey data in combination with 2012 airborne LiDAR data, 2009–2012 terrestrial LiDAR data and 2007 colour aerial photography. The base digital elevation model (DEM) is compiled from an ice-cap wide airborne LiDAR dataset. The mapped glacial landforms are dominated by sequences of recessional moraines laid down in the mid-Holocene, the Little Ice Age, and the last ∼100 years; the state of landform preservation generally decreasing with age. Interspersed with glaciofluvial sedimentation associated with typical ice-marginal retreat sequences is key geomorphological evidence of high-magnitude volcanogenic outburst floods (jökulhlaups) associated with the eruptions of Öraefajökull in 1362 and 1727 CE. Ice-front retreat has accelerated since c.2005 leaving a rapidly evolving buried-ice landscape in front of Virkisjökull-Falljökull – including an ice-cored esker, a large ice-floored (supraglacial) lake, and numerous actively forming kettle holes and ice caverns. This map could act as a ‘reference frame’ for geomorphologists studying the temporal evolution of glacial landform-sediment assemblages undergoing rapid change
European trial of free light chain removal by extended haemodialysis in cast nephropathy (EuLITE): A randomised control trial
<p>Abstract</p> <p>Background</p> <p>Renal failure is a frequent complication of multiple myeloma and when severe is associated with a greatly increased morbidity and mortality. The principal cause of severe renal failure is cast nephropathy, a direct consequence of high concentrations of monoclonal free light chains (FLCs) in patients' sera. FLC removal by extended haemodialysis, using a high cut-off dialyser, has recently been described as a novel therapeutic option.</p> <p>Methods</p> <p>The <b>EU</b>ropean trial of free <b>LI</b>ght chain removal by ex<b>TE</b>nded haemodialysis in cast nephropathy (EuLITE) trial is a prospective, randomised, multicentre, open label clinical trial to investigate the clinical benefits of FLC removal haemodialysis in patients with cast nephropathy, dialysis dependent acute renal failure and <it>de novo </it>multiple myeloma. Recruitment commenced in May 2008. In total, 90 patients will be recruited. Participants will be randomised, centrally, upon enrolment, to either trial chemotherapy and FLC removal haemodialysis or trial chemotherapy and standard high flux haemodialysis. Trial chemotherapy consists of bortezomib, doxorubicin and dexamethasone. FLC removal haemodialysis is undertaken with two Gambro HCO 1100 dialysers in series using an intensive treatment schedule. The primary outcome for the study is independence of dialysis at 3 months. Secondary outcomes are: duration of dialysis, reduction in serum FLC concentrations; myeloma response and survival.</p> <p>Hypothesis</p> <p>FLC removal haemodialysis will increase the rate of renal recovery in patients with severe renal failure secondary to cast nephropathy in <it>de novo </it>multiple myeloma.</p> <p>Trial registration</p> <p>ISRCTN45967602</p
The geomorphology of Svínafellsjökull and Virkisjökull-Falljökull glacier forelands, southeast Iceland
E-nursing homes: transforming access to nurses in nursing homes in response to the staffing crisis
The UK is facing a nationwide staffing crisis within adult social care, due to difficulties in recruiting and retaining registered nurses. Current interpretation of legislation means nursing homes must always have the physical presence of a registered nurse on duty within the home. With the shortage of registered nurses increasing, reliance on agency workers is commonplace, a practice impacting service cost and continuity of care. Lack of innovation to tackle this issue means the question of how to transform service delivery to combat staffing shortages is open for debate. The potential for technology to augment the provision of care was highlighted during the COVID-19 pandemic. In this article the authors present one possible solution focused on the provision of digital nursing care within nursing homes. Anticipated benefits include enhanced accessibility of nursing roles, reduced risk of viral spread and opportunities for upskilling staff. However, challenges include the current interpretation of legislation
Serum free light chain measurement aids the diagnosis of myeloma in patients with severe renal failure
<p>Abstract</p> <p>Background</p> <p>Monoclonal free light chains (FLCs) frequently cause rapidly progressive renal failure in patients with multiple myeloma. Immunoassays which provide quantitative measurement of FLCs in serum, have now been adopted into screening algorithms for multiple myeloma and other lymphoproliferative disorders. The assays indicate monoclonal FLC production by the presence of an abnormal κ to λ FLC ratio (reference range 0.26–1.65). Previous work, however, has demonstrated that in patients with renal failure the FLC ratio can be increased above normal with no other evidence of monoclonal proteins suggesting that in this population the range should be extended (reference range 0.37–3.1). This study evaluated the diagnostic sensitivity and specificity of the immunoassays in patients with severe renal failure.</p> <p>Methods</p> <p>Sera from 142 patients with new dialysis-dependent renal failure were assessed by serum protein electrophoresis (SPE), FLC immunoassays and immunofixation electrophoresis. The sensitivity and specificity of the FLC ratio's published reference range was compared with the modified renal reference range for identifying patients with multiple myeloma; by receiver operating characteristic curve analysis.</p> <p>Results</p> <p>Forty one patients had a clinical diagnosis of multiple myeloma; all of these patients had abnormal serum FLC ratios. The modified FLC ratio range increased the specificity of the assays (from 93% to 99%), with no loss of sensitivity. Monoclonal FLCs were identified in the urine from 23 of 24 patients assessed.</p> <p>Conclusion</p> <p>Measurement of serum FLC concentrations and calculation of the serum κ/λ ratio is a convenient, sensitive and specific method for identifying monoclonal FLC production in patients with multiple myeloma and acute renal failure. Rapid diagnosis in these patients will allow early initiation of disease specific treatment, such as chemotherapy plus or minus therapies for direct removal of FLCs.</p
Submarine evidence of ice-streaming and ice-sheet re-advance of the British Ice Sheet
A number of major ice streams have been identified within the Pleistocene British–Irish Ice Sheet (BIIS), primarily based on onshore mapping and single beam bathymetric datasets offshore (e.g. Bradwell et al., 2008). The identification of these ice streams is crucial to better understand the flow pattern and demise of the last BIIS, although evidence is currently lacking for key marine sectors such as the North Sea Basin. An improved understanding of the past cycles of glaciation, timing and extent, has far reaching implications for better understanding global climate change and ice-sheet behaviour.
This work focuses on the offshore geomorphological signature of the ice sheet sector referred to as the North Sea Lobe. New interpretations derived from high-resolution multibeam echosounder data and single-beam echosounder bathymetry data have been viewed in conjunction with onshore topographic digital surface models (NEXTMap). Derived layers of rugosity, slope, bathymetric positioning index and aspect were utilised during geomorphological mapping. Where available, multibeam backscatter intensity data have also been utilised as part of a semi-automated approach to identify areas of glacigenic deposits.
Mega-scale glacial lineations and drumlin fields indicate the North Sea Lobe was fed by an ice stream emanating from the Forth–Tay catchment in central Scotland. Large arcuate moraine ridges, smaller-scale moraine ridges and grounding-zone wedges indicate a complex advance, recession and re-advance of the North Sea Lobe during the Last Glacial Maximum
Peer reviewers in 2017
Pockmarks are seabed depressions that represent primary evidence of rapid biogenic/thermogenic gas build up and fluid release from seabed sediments to the water column. We use a Geographical Information System (GIS) to analyse multibeam echo-sounder bathymetric data and use a range of semi-automated tools to map seabed pockmarks in fjords and adjacent coastal waters around western Scotland. We map 1019 individual pockmarks in 12 different hydrographic areas covering ca. 2019 km2. We use morphological metrics and statistical procedures to classify and analyse the variety of pockmark forms. A k-means clustering algorithm identifies three classes of pockmark morphology: deep, elongate and regular. The recognition of separate pockmark classes could aid understanding of their age, activity and origin. This work presents the first detailed mapping of pockmark fields in Scottish west coast waters and highlights the use of pockmarks as an indicator of the quantity, mobility and fate of stored carbon
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