Winter weather controls net influx of atmospheric CO2 on the north-west European shelf

Shelf seas play an important role in the global carbon cycle, absorbing atmospheric carbon dioxide (CO2) and exporting carbon (C) to the open ocean and sediments. The magnitude of these processes is poorly constrained, because observations are typically interpolated over multiple years. Here, we used 298500 observations of CO2 fugacity (fCO2) from a single year (2015), to estimate the net influx of atmospheric CO2 as 26.2 ± 4.7 Tg C yr-1 over the open NW European shelf. CO2 influx from the atmosphere was dominated by influx during winter as a consequence of high winds, despite a smaller, thermally-driven, air-sea fCO2 gradient compared to the larger, biologically-driven summer gradient. In order to understand this climate regulation service, we constructed a carbon-budget supplemented by data from the literature, where the NW European shelf is treated as a box with carbon entering and leaving the box. This budget showed that net C-burial was a small sink of 1.3 ± 3.1 Tg C yr-1, while CO2 efflux from estuaries to the atmosphere, removed the majority of river C-inputs. In contrast, the input from the Baltic Sea likely contributes to net export via the continental shelf pump and advection (34.4 ± 6.0 Tg C yr-1).

Nitrogen dynamics and phytoplankton community structure: the role of organic nutrients

Dissolved organic nitrogen (DON) is recognised as an important N source for phytoplankton. However, its relative importance for phytoplankton nutrition and community composition has not been studied comprehensively. This study, conducted in a typical Scottish fjord, representative of near-pristine coastal environments, evaluates the utilisation of DON and dissolved inorganic nitrogen (DIN) by different microbial size fractions and the relationship of phytoplankton community composition with DON and other parameters. The study demonstrated that DON was important in supporting phytoplankton throughout the yearly production cycle. The higher-than-expected urea uptake rates and large fraction of the spring bloom production supported by DON suggested that organic N not only contributes to regenerated production and to the nutrition of the small phytoplankton fraction, but can also contribute substantially to new production of the larger phytoplankton in coastal waters. Multivariate statistical techniques revealed two phytoplankton assemblages with peaks in abundance at different times of the year: a spring group dominated by Skeletonema spp., Thalassiosira spp., and Pseudo-nitzschia spp. group delicatissima; and a summer/autumn group dominated by Chaetoceros spp., Scrippsiella spp., and Pseudo-nitzschia spp. group seriata. The multivariate pattern in community composition and abundance of these taxa was significantly correlated with the multivariate pattern of DON, urea, dissolved free amino acids, DIN, temperature, salinity, and daylength, with daylength and urea being particularly important, suggesting both physical and chemical controls on community composition.

Chemical forms and extractability of iron in sediments of three contrasting lakes of China and UK

Iron is a limiting factor for the eutrophication of lakes, especially those lakes that are enriched with phosphorus. Extractability of iron in sediments of West Lake and Taihu Lake in China and Lower Lough Erne in Northern Ireland of UK was comparatively investigated on the basis of analysing chemical forms of iron using different extractants. It was shown that extractable iron in sediments of the lakes was greatly different using various extractants. Reactive iron or easily released iron such as "active" iron oxides, total free iron oxide and water-soluble iron was not high, only accounting for 0.01%-0.15% of total iron. The efficiency of the extractants for exchangeable iron was decreased in the sequence 0.1 mol/L HCl >> DTPA + TEA mixed solution > 1 mol/L NH4OAc > 0.5 mol/L MgCl2 = 0.5 mol/L CaCl2. It seems that the complexion of iron by organic matter was not strong because the concentration of organically bound iron was significantly lower than the concentration it was forecasted. Extractable iron is not entirely consistent with or dependent on total iron in lake sediments. To a certain extent, phosphate can inhibit the release of iron in sediments of the lakes. The selection of extractants is thus the first key step to evaluate bioavailability of iron in lake sediments.

The prevalence and effect of alcohol and drug abuse on cohort-matched critically injured patients

A prospective study was undertaken at a Level I trauma center to evaluate the prevalence of substance use among victims of major trauma, along with the impact on clinical outcome. Five hundred sixteen patients had urine toxicology and blood alcohol screens performed and correlated with pattern and severity of injury, hospital course, and outcome. Three hundred seventy-one patients (71%) screened positive for alcohol or drugs, or both. Fifty-two per cent had positive alcohol screens, and 42 per cent had positive drug screens (cocaine and opiates represented 91% of positive drug screens). Univariate analysis revealed patterns of alcohol/drug use varied among subgroups according to demographics (less use among patients older than 55 years, females and Asians; more drug use in blacks; more alcohol use in Hispanics), mechanism of injury (non-use in blunt trauma patients and use of both in penetrating trauma patients) and body region injured (non-use in head-injured patients). Septic complications and mortality were more correlative with severity of injury, but not with use or non-use of alcohol or drugs. We conclude that alcohol and drug use remains a major comorbid factor in major trauma, and that injury prevention efforts should include a strong focus on counseling regarding these lifestyle choices.

The effect of amalgam overhangs on alveolar bone height as a function of patient age and overhang width

The purpose of this study was to compare the effects of amalgam restorations with and without overhangs on alveolar bone loss via digitized radiographs for subjects of varying ages and overhang widths. The first phase of this study compared the alveolar bone loss among teeth with clinically acceptable two-surface amalgam restorations with a control surface on the same tooth. The second phase was similar to the first phase with the exception that it compared defective amalgam restorations (those containing amalgam overhanging approximal margins) with the control surface on the same tooth. The collected data showed a significant loss of alveolar bone as a result of amalgam overhang presence (P < 0.02). However, overhang width and patient age did not affect the significance of the detrimental effects of the amalgam overhangs. Overall alveolar bone height was seen to decrease with patient age, independent of amalgam restorations. Digital radiography was seen to be an accurate method for evaluating alveolar bone height changes due to the local environment created by overhanging amalgam margins.

Complications and nonclosure rates of fasciotomy for trauma and related risk factors

The objective of this study was to identify risk factors for the development of complications and unsatisfactory skin closure following fasciotomy for trauma. Risk factors included in the study are prolonged time from injury to fasciotomy, type of fasciotomy, site of injury, and kind of underlying injury. The study was a retrospective analysis of 100 consecutive fasciotomies done for trauma over a period of 38 months (December 1991 to January 1995) in a "level I" trauma center at a university-affiliated county teaching hospital. Ninety-four patients were eligible for analysis, 29 of whom (31%) developed complications at the fasciotomy site. The risk was increased for lower extremity versus upper extremity (34.3% versus 20.8%), prophylactic versus therapeutic (42.0% versus 24.6%), late (>8 hours) versus early (37% versus 25%), and vascular versus musculoskeletal (38.8% versus 22.2%) trauma cases. The same risk factors negatively influenced the ability to close the skin primarily. The four subgroups defined by vascular/nonvascular injury and upper/lower extremity site had significantly different nonclosure rates (p = 0.043). The rate was highest among the vascular/lower extremity group (60.5%) and lowest among the nonvascular/upper extremity group (15.4%). We concluded that fasciotomies in lower extremities, the presence of underlying vascular injuries, fasciotomies performed prophylactically, and a time between the injury and fasciotomy of more than 8 hours are associated with an increased risk for local complications. The same factors are associated with an increased need for skin grafting the wound.

An evolutionary concept analysis of mentoring in nursing

Despite widespread evidence of the concept of mentoring in nursing, it has been largely undefined, borrowed from other disciplines, viewed as static, and/or confused with related terms. Building on the work of Yoder and using a literature-based method developed by Rodgers, an evolutionary concept analysis is presented to provide an understanding of the meaning of mentoring in nursing, its current status, and the conceptual clarity necessary for additional systematic and rigorous inquiry. A random sample of 82 research abstracts and journal articles, representing 26 per cent of the total population of literature, was used to extract six essential attributes of the concept: a teaching-learning process, a reciprocal role, a career development relationship, a knowledge or competence differential between participants, a duration of several years, and a resonating phenomenon. These attributes form the theoretical definition of mentoring in nursing. Antecedents, consequences, related concepts, and empirical referents are presented. A model case, encompassing all of the critical attributes, depicts the Investigators' mentoring experience. Major changes in mentoring are viewed within the context of nursing as a learned profession, a legitimate academic enterprise, and a clinical science. Implications for further development are posed to further mentoring as a process for the socialization of nurse scholars and scientists and the proliferation of a body of professional knowledge.

Penetrating cardiac injuries

Penetrating cardiac injuries pose a tremendous challenge to any trauma surgeon. Time, sound judgment, aggressive intervention, and surgical technique are the most important factors contributing to positive outcomes. This article extensively reviews the history, surgical management, and techniques needed to deal with these critical injuries. This year commemorates the one hundredth anniversary of the first successful repair of a cardiac injury.

Chronic benign congenital myopathy: fingerprint body type

The term “benign congenital myopathy” describes a group of muscle disorders characterized by proximal or diffuse muscle weakness, a relatively non-progressive course, normal serum muscle enzyme assays and the presence of a distinctive morphological feature. We report here a 55 year old woman, with fingerprint body myopathy who exhibits all of the above features. She has been affected from birth, able to walk since the age of 12, and has not deteriorated in the past thirty years. Muscle biopsy reveals fatty infiltration, numerous small fibers undergoing structural change, good differentiation into type I and II fibers, and excessive intracellular lipid and lipochrome. Only on electron microscopic study is the distinctive feature of numerous subsarcolemmal round to ovoid fingerprint bodies observed. Many fibers also contain large collections of tubular aggregates, filamentous bodies, and autophagic vacuoles.

The fingerprint bodies are similar to the ones described by A. Engel in a 5 year old girl. Thus, a rare opportunity is provided to study an individual who has had this disease for over fifty years.