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A revision of Begonia sect. Symbegonia, endemic to New Guinea, is presented, with descriptions of five new species (B. arauensis M.Hughes, B. asaroensis J.Gagul, B. erodiifolia Sands, B. mimikaensis Sands and B. vinkii Sands). There are 18 species now recognised, and a key is provided for their identification. Ten of the species are assessed to belong to the IUCN category Data Deficient, and eight to Least Concern.
Recent studies have improved our understanding of nearshore marine ecosystems surrounding Ascension Island (central Atlantic Ocean), but little is known about Ascension's benthic environment beyond its shallow coastal waters. Here, we report the first detailed physical and biological examination of the seabed surrounding Ascension Island at 100–1000 m depth. Multibeam swath data were used to map fine scale bathymetry and derive seabed slope and rugosity indices for the entire area. Water temperature and salinity profiles were obtained from five Conductivity, Temperature, Depth (CTD) deployments, revealing a spatially consistent thermocline at 80 m depth. A camera lander (Shelf Underwater Camera System; SUCS) provided nearly 400 images from 21 sites (100 m transects) at depths of 110–1020 m, showing high variability in the structure of benthic habitats and biological communities. These surveys revealed a total of 95 faunal morphotypes (mean richness >14 per site), complemented by 213 voucher specimens constituting 60 morphotypes collected from seven targeted Agassiz trawl (AGT) deployments. While total faunal density (maximum >300 m−2 at 480 m depth) increased with rugosity, characteristic shifts in multivariate assemblage structure were driven by depth and substratum type. Shallow assemblages (~100 m) were dominated by black coral (Antipatharia sp.) on rocky substrata, cup corals (Caryophyllia sp.) and sea urchins (Cidaris sp.) were abundant on fine sediment at intermediate depths (250–500 m), and shrimps (Nematocarcinus spp.) were common at greater depths (>500 m). Other ubiquitous taxa included serpulid and sabellid polychaetes and brittle stars (Ophiocantha sp.). Cold-water corals (Lophelia cf. pertusa), indicative of Vulnerable Marine Ecosystems (VMEs) and representing substantial benthic carbon accumulation, occurred in particularly dense aggregations at <350 m but were encountered as deep as 1020 m. In addition to enhancing marine biodiversity records at this locality, this study provides critical baseline data to support the future management of Ascension's marine environment.
In the wide-field Panoramic Imaging Survey of Centaurus and Sculptor (PISCeS), we investigate the resolved stellar halos of two nearby galaxies (the elliptical Centaurus A and the spiral Sculptor, D ~ 3.7 Mpc) out to a projected galactocentric radius of 150 kpc with Magellan/Megacam. The survey has led to the discovery of ~20 faint satellites to date, plus prominent streams and substructures in two environments that are substantially different from the Local Group, i.e. the Centaurus A group dominated by an elliptical and the loose Sculptor group of galaxies. These discoveries clearly attest to the importance of past and ongoing accretion processes in shaping the halos of these nearby galaxies, and provide the first census of their satellite systems down to an unprecedented MV < −8. The detailed characterization of the stellar content, shape and gradients in the extended halos of Sculptor, Centaurus A, and their dwarf satellites provides key constraints on theoretical models of galaxy formation and evolution.
Four epitaxial ScN(001) thin films were successfully deposited on MgO(001) substrates by dc reactive magnetron sputtering at 2, 5, 10, and 20 mTorr in an Ar/N2 ambient atmosphere at 650 °C. The microstructure of the resultant films was analyzed by x-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Electrical resistivity, electron mobility and concentration were measured using the room temperature Hall technique, and temperature dependent in-plain measurements of the thermoelectric properties of the ScN thin films were performed. The surface morphology and film crystallinity significantly degrade with increasing deposition pressure. The ScN thin film deposited at 20 mTorr exhibits the presence of <221> oriented secondary grains resulting in decreased electric properties and a low thermoelectric power factor of 0.5 W/mK2 at 800 K. The ScN thin films grown at 5 and 10 mTorr are single crystalline, yielding the power factor of approximately 2.5 W/mK2 at 800 K. The deposition performed at 2 mTorr produces the highest quality ScN thin film with the electron mobility of 98 cm2 V−1 s−1 and the power factor of 3.3 W/mK2 at 800 K.
Papillary microcarcinoma of the thyroid has been described as either a normal variant or a serious malignancy. We describe our experience with papillary microcarcinoma and lymph node metastases.
A total of 685 consecutive total thyroidectomies with central compartment neck dissection were reviewed for papillary microcarcinoma. Association of central compartment lymph node metastases with age, gender, tumour multifocality, bilaterality and extrathyroidal extension was analysed.
Out of 170 papillary microcarcinoma cases, multifocality was found in 72 (42.4 per cent), bilaterality in 49 (28.8 per cent) and extrathyroidal extension in 16 (9.4 per cent). In all, 23 patients (13.5 per cent) had lymph node metastases. There was a significant association (p < 0.05) between extrathyroidal extension (but no other tumour characteristics) and lymph node metastases.
In all, 13.5 per cent of papillary microcarcinomas in our series showed lymph node metastases. Lymph node metastases were associated with extrathyroidal invasion of the papillary microcarcinoma.
A high occurrence rate of consanguineous marriages may favour the onset and increased frequency of autosomal recessive diseases in a population. The population of Monte Santo, Bahia, Brazil, has a high frequency of rare genetic diseases such as mucopolysaccharidosis type VI, whose observed frequency in this population is 1:5000, while the incidence of this disease recorded in other regions of the world varies from 1:43,261 in Turkey to 1:1,505,160 in Switzerland. To verify the influence of consanguineous marriage on the increased frequency of observed genetic diseases in this population, the population structure and frequency of different types of marriage during different time periods were evaluated. A total of 9765 marriages were found in an analysis of parish marriage records from the city. Over three periods, 1860–1895, 1950–1961 and 1975–2010, the inbreeding rates were 37.1%, 13.2% and 4.2% respectively. Although there was a high rate of inbreeding, endogamic marriages were the dominant marriage type in all three periods. In the most recent period, there was an increase in the number of exogamous marriages and those among immigrants, but most of these occurred among individuals from cities that neighbour Monte Santo. The low rate of migration and high frequency of endogamic and consanguineous marriages show that growth of this population is predominantly internal and could explain the occurrence, and increase in frequency, of recessive genetic diseases in the city.
Las Cumbres Observatory Global Telescope Network (LCOGT) is currently building a new kind of general-purpose astronomical facility: a fully robotic network of telescopes of 2m, 1m and 0.4m apertures and homogeneous instrumentation. A pan-network approach to scheduling (rather than per individual telescope) offers redundancy in the event of poor weather or technical failure, as well as the ability to observe a target around the clock. Here we describe the network design and instrumentation under development, together with the main science programmes already being lead by LCOGT staff.
Data about the effectiveness of different antibiotic regimens for the treatment of acute Q fever from clinical studies is scarce. We analysed the antibiotic treatment regimens of acute Q fever patients in 2007 and 2008 in The Netherlands and assessed whether hospitalization after a minimum of 2 days antibiotic therapy was related to the initial antibiotic therapy. Clinical data on antibiotic treatment and risk factors of acute Q fever patients were obtained from general practitioner medical records and self-reported by patients. For the 438 study patients, doxycycline was the most commonly prescribed initial antibiotic in both study years. After adjustments for confounding factors, doxycycline (200 mg/day), moxifloxacin, as well as other possibly effective antibiotics [including other new fluoroquinolones and doxycycline (100 mg/day)] showed significant lower risks for hospitalization compared to β-lactam antibiotics and azithromycin (reference group), with the lowest risk for doxycycline (200 mg/day) (odds ratio 0·04, 95% confidence interval 0·01–0·22). These data support current guidelines that recommend doxycycline as the first choice antibiotic for treating acute Q fever.
To assess the general health and activity levels of 4- and 5-year-old children after intervention for congenital cardiac disease.
Health behaviour outcomes were assessed in 91 children who had surgery or catheter intervention for congenital cardiac disease. The children were classified into four groups according to severity. The main parameters of classification were the presence of residual symptoms, frequency of visits to general practitioner or the Accident and Emergency Department, and ability to participate in physical activity according to a calculated “activity score”.
Children had very few residual symptoms after “corrective surgery”. Those with complex congenital cardiac disease post-Fontan-type repair still had symptoms on average 18.2 days per month. Surprisingly, the complex group had fewer days “sick” from non-cardiac causes and had fewer visits to general practitioner or Accident and Emergency Departments. Regression analysis indicates that three variables had significant relevance to the general practitioner or Accident and Emergency visits: complex congenital cardiac disease, fewer visits; Townsend score – more deprivation – more visits; and maternal worry – higher maternal worry score – more visits. Regression analysis indicates that lower activity score is significantly related to complex cardiac disease and higher maternal worry score.
The majority of this group of 4- and 5-year-old children had few residual symptoms and had good exercise tolerance. Maternal worry is a significant factor in influencing both activity levels and frequency of unscheduled health service demands – general practitioner or Accident and Emergency visits.
The UK has some important natural fish communities, which require active conservation via habitat protection and ensuring that other fish species that may upset the existing ecological balance are not introduced to these key sites.
Where sites contain Lampreys, Vendace, Shad, whitefish, Smelt, Charr Salvelinus alpinus, Bullhead or other fish species of conservation concern, information on the status of stocks is particularly important.
Whether a fish stock is self-sustaining in the long term is an important attribute: some exploited freshwater fish (e.g. Brown Trout Salmo trutta) are now routinely stocked with hatchery-reared individuals. Stocking can have impacts on locally adapted fish populations, and stocked fish can give the impression that a population is abundant when, in fact, it is not self-sustaining. The distribution of successfully reproducing fish is a valuable measure of the ecological condition of a given river system. Tributaries or main river stretches in which fish are unable to spawn successfully may indicate, for instance, habitat degradation of various forms or barriers to migration. Fisheries surveys can therefore produce important insights into the health of the overall aquatic environment.
All natural fish stocks fluctuate in abundance in response to changing environmental conditions and degrees of exploitation. Any single measure of abundance is therefore of limited value unless it is viewed in the context of historical change. Long-term catch records, for instance for Atlantic salmon Salmo salar, can be particularly valuable in helping to determine likely trends in population abundance.
Bonding of polished, polycrystalline diamond films to silicon was performed in ultra high vacuum at 32 MPa of applied uniaxial stress. The transmission electron microscopy (TEM) investigation revealed that the interface of all bonded samples was non-uniform. An abrupt boundary between the two wafers existed only in some parts of the interface, while other parts contained an amorphous interlayer of up to 40 nm in thickness. Electron energy loss spectroscopy (EELS) revealed that this interlayer consisted of oxygen, carbon and silicon. Based on comparison of the microstructure and chemical composition of the interface formed at different bonding temperatures, we propose a model for the silicon/diamond wafer fusion process.
To assess the resource utilization associated with sepsis syndrome in academic medical centers.
Prospective cohort study.
Eight academic, tertiary-care centers.
Stratified random sample of 1,028 adult admissions with sepsis syndrome and all 248,761 other adult admissions between January 1993 and April 1994. The main outcome measures were length of stay (LOS) in total and after onset of sepsis syndrome (post-onset LOS) and total hospital charges.
The mean LOS for patients with sepsis was 27.7 ± 0.9 days (median, 20 days), with sepsis onset occurring after a mean of 8.1 ± 0.4 days (median, 3 days). For all patients without sepsis, the LOS was 7.2 ± 0.03 days (median, 4 days). In multiple linear regression models, the mean for patients with sepsis syndrome was 18.2 days, which was 11.0 days longer than the mean for all other patients (P < .0001), whereas the mean difference in total charges was $43,000 (both P < .0001). These differences were greater for patients with nosocomial as compared with community-acquired sepsis, although the groups were similar after adjusting for pre-onset LOS. Eight independent correlates of increased post-onset LOS and 12 correlates of total charges were identified.
These data quantify the resource utilization associated with sepsis syndrome, and demonstrate that resource utilization is high in this group. Additional investigation is required to determine how much of the excess post-onset LOS and charges are attributable to sepsis syndrome rather than the underlying medical conditions.
For the fabrication of bulk strained Si devices, a thin Si layer is deposited on a virtual substrate consisting of a several μm thick compositionally graded SiGe layer. A simpler approach utilizing H or He implantation to enhance relaxation of a thin SiGe film was recently reported. In this current work, hydrogen implantation is used to enhance the SiGe relaxation; and, relaxation beyond the previous reported limit is demonstrated. Experiments are performed on CVD deposited SiGe films with Ge fractions ranging from 20% to 40 % and thickness in the range of 100nm to about 500nm. After annealing at 800°C, relaxation of more than 80% is achieved. PMOS and NMOS devices are successfully fabricated and much enhanced hole and electron mobilities are demonstrated.
A KrF (248 nm) excimer laser with a 38 ns pulse width was used to study pulsed laser annealing of AIN/GaN bi-layers and dopant activation of Mg-implanted GaN thin films. For the AIN/GaN bi-layers, cathodoluminescence (CL) showed an increase in the intensity of the GaN band-edge peak at 3.47 eV after pulsed laser annealing at an energy density of 2000 mJ/cm2. Rutherford backscattering spectrometry of a Mg-implanted A1N (75 nm thick)/GaN (1.0 μm thick) thin-film heterostructure showed a 20% reduction of the 4He+ backscattering yield after laser annealing at an energy density of 400 mJ/cm2. CL measurements revealed a 410 nm emission peak indicating the incorporation of Mg after laser processing.
Using first-principles electronic structure calculations based on the Linear-Muffin-Tin Orbital (LMTO) method, we have investigated the effects of interstitial boron and hydrogen on the electronic structure of the L12 ordered intermetallic Ni3A1. When it occupies an octahedral interstitial site entirely coordinated by six Ni atoms, we find that boron enhances the charge distribution found in the strongly-bound “pure” Ni3AI crystal: Charge is depleted at Ni and Al sites and enhanced in interstitial region. Substitution of Al atoms for two of the Ni atoms coordinating the boron, however, reduces the interstitial charge density between certain atomic planes. In contrast to boron, hydrogen appears to deplete the interstitial charge, even when fully coordinated by Ni atoms. We suggest that these results are broadly consistent with the notion of boron as a cohesion enhancer and hydrogen as an embrittler.
To provide a sensitive measurement of the effect of boron segregation on the strength and ductility of Ni3A1 grain boundaries, bicrystal tensile tests were performed on small specimens of boron doped Ni76A124 cut from extremely large-grained boules. Five specimens with the same “random” or low-symmetry grain boundary (disorientations measured by means of backscattered Kikuchi patterns) and two specimens with a second random grain boundary were tested in quenched and slow-cooled conditions. Duplicate tests performed in a low (7 ppm) water-vapor environment showed that the fracture mode and the stress and strain at fracture are altered by environmental embrittlement at individual, partially strengthened grain boundaries.
The results of comparison investigations of structural and electric parameters changes in silicon systems induced by pulsed magnetic field (MF) treatment (PMFT) are presented for the first time. The characteristics of (PMFT) that can induce considerable parameters changes of the silicon system were determined. Amplitudc of thc magnctic impulscs is 0.1-0.3 MA/m and duration of thc impulscs is 10-30 ms. The investigations were carried out by means of scanning electron microscope (SEM), X-ray diffraction analysis, C-V and DLTS spectroscopies. The PMFT induces the generation of A-centers in the near-surface region of silicon, the changes of the crystal lattice parameter and the concentration of free electrons and results in emergence of an extent structural microdefects in subsurface. The obtained experimental data testifies that PMFT is possible to increase the vacancy concentration at subsurface region of silicon.
Epitaxial SiGe/Si layers are being extensively investigated for use in base regions of high-speed heterojunction bipolar-transistors (HBTs). Extended defects can be formed in SiGe/Si layers by ion-implantation. Defects, once formed in the layers, can negatively impact electrical performance and also future reliability of the HBTs. The present study investigates the interaction between selective-implant damage and strained SiGe/Si layers of sub-critical thickness. Implant-damage is observed to form dislocation-sources at the edges of implanted regions in SiGe/Si heterolayers. The dislocation sources produce glide dislocation loops. Segments of these loops glide down to SiGe/Si interfaces causing misfit dislocations to arise at interfaces in the heterolayers. Misfitdislocations are formed in directions parallel to and perpendicular to the <110> edge of the implanted region. Dislocations propagate out to a distance of ∼100-150 nm past the edge of the implant in the case of Si0.9Ge0.1/Si layers of sub-critical thickness. The origin and behavior of these defects is discussed.