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The fundamental quantity for the total solar irradiance is the solar constant J which is determined by the mean Sun-Earth distance and by the energy budget in the interior of the sun. The mean distance is the major semi-axis of the earth orbit and therefore a constant of celestial mechanics. The energy production and transport in the interior of the sun must be constant at least during a Helmholtz-Kelvin period. Actually, the heat budget of the sun is constant during some billion years.
The dark spots on the solar disk, some of them are visible with the naked eye, and the aurorae, especially those strectching down to the tropics, are the best visible manifestations of the solar activity. Since more than one century, we know that this activity follows a regular periodic cycle of 11-years (Heinrich Schwabe 1844), but with an intensity, which is sufficiently variable, to speak of “small” and “large” solar cycles.
The U.S. Geological Survey, at the Denver Federal Center, Lakewood, Colorado assays C14 concentration of water samples using liquid scintillation techniques. The laboratory synthesizes benzene from precipitated barium carbonate using techniques described by Noakes, Kim, and Akers (1967). Three ml of the synthesized benzene is pipetted into a tared, low potassium-40 glass vial. The sample is weighed and 1ml of a scintillation solution is added to the vial. The scintillation solution used is a mixture of 10g PPO and 0.025g dimethyl-POPOP scintillators in 250ml toluene. Calculations of dates are made with the radiocarbon half-life of 5568 years; plus or minus numbers quoted herein are the standard error for the counting of radioactive disintegrations.
This list includes all measurements made between 1969 and 1973 that represent natural samples. Physical and chemical treatment of samples and counting technique remain as previously reported (R, 1973, v 15, p 469-478). Calculations of dates are made with the radiocarbon half-life of 5568 ± 30 years; plus or minus numbers quoted herein are the standard errors for the counting of radioactive disintegrations.
Impairments in facial emotion recognition (FER) have been detected in patients with Parkinson disease (PD). Presently, we aim at assessing differences in emotion recognition performance in PD patient groups with and without mild forms of cognitive impairment (MCI) compared to healthy controls.
Performance on a concise emotion recognition test battery (VERT-K) of three groups of 97 PD patients was compared with an age-equivalent sample of 168 healthy controls. Patients were categorized into groups according to two well-established classifications of MCI according to Petersen's (cognitively intact vs. amnestic MCI, aMCI, vs. non-amnestic MCI, non-aMCI) and Litvan's (cognitively intact vs. single-domain MCI, sMCI, vs. multi-domain MCI, mMCI) criteria. Patients and controls underwent individual assessments using a comprehensive neuropsychological test battery examining attention, executive functioning, language, and memory (Neuropsychological Test Battery Vienna, NTBV), the Beck Depression Inventory, and a measure of premorbid IQ (WST).
Cognitively intact PD patients and patients with MCI in PD (PD-MCI) showed significantly worse emotion recognition performance when compared to healthy controls. Between-groups effect sizes were substantial, showing non-trivial effects in all comparisons (Cohen's ds from 0.31 to 1.22). Moreover, emotion recognition performance was higher in women, positively associated with premorbid IQ and negatively associated with age. Depressive symptoms were not related to FER.
The present investigation yields further evidence for impaired FER in PD. Interestingly, our data suggest FER deficits even in cognitively intact PD patients indicating FER dysfunction prior to the development of overt cognitive dysfunction. Age showed a negative association whereas IQ showed a positive association with FER.
We propose that the collision rates of non-spherical particles settling in a turbulent environment are significantly higher than those of spherical particles of the same mass and volume. The theoretical argument is based on the dependence of the particle drag force on the particle orientation, thus varying gravitational settling velocities, which can remain different until contact due to the particle inertia. Therefore, non-spherical particles can collide with large relative velocities. Direct numerical simulations (DNS) of streamwise decaying isotropic turbulence seeded with small, heavy, rotationally symmetric ellipsoids of five different aspect ratios are performed to confirm these arguments. The motion of 21 million ellipsoids is tracked by a Lagrangian particle solver assuming creeping flow conditions and neglecting the influence of the particles on the flow. We find that ellipsoids collide considerably more often than spherical particles of the same volume and mass due to a drastically increased mean relative velocity at contact.
The Dawn spacecraft orbited Asteroid (4) Vesta for a year, and returned disk-resolved images and spectra covering visible and near-infrared wavelengths at scales as high as 20 m/pix. The visible geometric albedo of Vesta is ~ 0.36. The disk-integrated phase function of Vesta in the visible wavelengths derived from Dawn approach data, previous ground-based observations, and Rosetta OSIRIS observations is consistent with an IAU H-G phase law with H=3.2 mag and G=0.28. Hapke's modeling yields a disk-averaged single-scattering albedo of 0.50, an asymmetry factor of -0.25, and a roughness parameter of ~20 deg at 700 nm wavelength. Vesta's surface displays the largest albedo variations observed so far on asteroids, ranging from ~0.10 to ~0.76 in geometric albedo in the visible wavelengths. The phase function of Vesta displays obvious systematic variations with respect to wavelength, with steeper slopes within the 1- and 2-micron pyroxene bands, consistent with previous ground-based observations and laboratory measurement of HED meteorites showing deeper bands at higher phase angles. The relatively high albedo of Vesta suggests significant contribution of multiple scattering. The non-linear effect of multiple scattering and the possible systematic variations of phase function with albedo across the surface of Vesta may invalidate the traditional algorithm of applying photometric correction on airless planetary surfaces.
Many specialty-specific functional somatic syndrome diagnoses exist to
describe people who are experiencing so-called medically unexplained
symptoms. Although cognitive–behavioural therapy can be effective in the
management of such syndromes, it is rarely available. A
cognitive–behavioural therapy suitable for group treatment of people with
different functional somatic syndromes could address this problem.
To test the efficacy of a cognitive–behavioural therapy (Specialised
Treatment for Severe Bodily Distress Syndromes, STreSS) designed for
patients with a range of severe functional somatic syndromes.
A randomised controlled trial (clinicaltrials.gov, NCT00132197) compared
STreSS (nine 3.5 h sessions over 4 months, n = 54) with
enhanced usual care (management by primary care physician or medical
specialist, n = 66). The primary outcome was improvement
in aggregate score on subscales of the 36-item Short Form Health Survey
(physical functioning, bodily pain and vitality) at 16 months.
Participants receiving STreSS had a greater improvement on the primary
outcome (adjusted mean difference 4.0, 95% CI 1.4–6.6, P
= 0.002) and on most secondary outcomes.
In the management of functional somatic syndromes, a
cognitive–behavioural group treatment was more effective than enhanced
In a previous study published in Astrobiology, we focused on the evolution of habitability of a 10 M⊕ super-Earth planet orbiting a star akin to the Sun. This study was based on a concept of planetary habitability in accordance with the integrated system approach that describes the photosynthetic biomass production taking into account a variety of climatological, biogeochemical and geodynamical processes. In the present study, we pursue a significant augmentation of our previous work by considering stars with zero-age main-sequence masses between 0.5 and 2.0 M⊙ with special emphasis on models of 0.8, 0.9, 1.2 and 1.5 M⊙. Our models of habitability consider geodynamical processes during the main-sequence stage of these stars as well as during their red giant branch evolution. Pertaining to the different types of stars, we identify the so-called photosynthesis-sustaining habitable zone (pHZ) determined by the limits of biological productivity on the planetary surface. We obtain various sets of solutions consistent with the principal possibility of life. Considering that stars of relatively high masses depart from the main-sequence much earlier than low-mass stars, it is found that the biospheric lifespan of super-Earth planets of stars with masses above approximately 1.5 M⊙ is always limited by the increase in stellar luminosity. However, for stars with masses below 0.9 M⊙, the lifespan of super-Earths is solely determined by the geodynamic timescale. For central star masses between 0.9 and 1.5 M⊙, the possibility of life in the framework of our models depends on the relative continental area of the super-Earth planet.
In situ ellipsometry reveals that particle formation influences the growth of glow discharge a-Si:H. This particle formation is observed even under discharge conditions leading to the deposition of device quality Material. It is found that less dense material is deposited during the particle-induced initial transient stage of the discharge which influences the properties of the subsequently growing “bulk” film. The effect of special power gradient ignition procedures is discussed. A significant increase of solar cell efficency is achieved by choosing “soft” start conditions for the i-layer deposition.
The effect of variation of the preparation parameters filament temperature Tfil, gas pressure p and hydrogen dilution (H2/SiH4-flow ratio) on the absorption spectra of microcrystalline silicon deposited by the hot-wire technique (hw-μc-Si:H) has been studied by means of Photothermal Deflection Spectroscopy (PDS). We find an enhanced absorption of the μc-Si:H compared to crystalline silicon in the band gap (defect absorption) as well as in the interband transition region. An increase of absorption has already been reported for μc-Si:H films prepared by different techniques. In the case of hw-pc-Si:H we observe a relation between the absorption enhancement and the crystallite size. Increasing the gas pressure from 35 to 400 mTorr (Tfil=1850°C) or the filament temperature from 1750°C to 1950°C (p=100mTorr) the crystallite sizes, deduced from X-ray diffraction measuements, range from 10 to 60 nm. An alteration of the hydrogen dilution by varying the flow ratio between 2.5 and 25 does not affect the crystallite size and the optical absorption remains constant. In our opinion the enhancement cannot be described by a simple superposition of an amorphous and a crystalline absorption coefficient weighted by the volume fractions of the amorphous and crystalline phase, respectively. The possible reasons for the enhanced absorption will be discussed. The variation of the crystallite size with deposition conditions offers the possibility to control the optical absorption of μc-Si:H which is important for incorporating the material either as window layers or intrinsic layers in solar cells.
Thrombolite and stromatolite reefs occur at several stratigraphic levels within the terminal Proterozoic Nama Group (c. 550–543 Ma) of central and southern Namibia. The reefs form integral parts of several carbonate platforms within the Nama Group, including the Kuibis platform of the northern Nama Basin (Zaris subbasin), and Huns platform (Witputs subbasin) of the southern Nama Basin. The reefs are composed of both thrombolites and stromatolites that form laterally continuous biostromes, isolated patch reefs, and isolated pinnacle reefs ranging in scale from a metre to several kilometres in width. In the majority of cases, the reefs occur stratigraphically as an integral facies within the transgressive systems tracts of sequences making up the Kuibis and Huns platforms. This suggests that a regime of increasing accommodation was required to form well-developed reefs, though reefs also occur sporadically in highstand systems tract settings. Within a given transgressive systems tract, a regime of increasing accommodation through time favours the transition from sheet-like biostromal geometries to more isolated patch and pinnacle biohermal geometries. Similarly, increasing accommodation in space, such as a transect down depositional dip, shows a similar transition from more sheet-like geometries in updip positions to more isolated geometries in downdip positions. Reefal facies consist of thrombolitic domes, columns and mounds with well-developed internal clotted textures, in addition to stromatolitic domes, columns and mounds, with crudely to moderately well-developed internal lamination. Stromatolites are better developed in conditions of relatively low accommodation, and updip locations, under conditions of higher current velocities and greater sediment influx. Thrombolites are better developed in conditions of relatively high accommodation and low sediment influx. Both types of microbialites are intimately associated with the first calcifying metazoan organisms, which may have attached themselves to the sediment surface or otherwise lived within sheltered depressions within the rough topography created by ecologically complex mats. The appearance of thrombolitic textures during terminal Proterozoic time is consistent with colonization of cyanobacterial mats by higher algae and metazoans, which would have been an important process in generating clotted textures. Fabrics in the Nama thrombolites are well preserved and show evidence of thrombolitic mesoclots being overgrown by fibrous marine carbonate, interpreted as former aragonite. This was followed by emplacement of geopetal micrite fills, and precipitation of dolomite as an isopachous rim cement, followed by occlusion of remaining porosity by blocky calcite spar.
In the German state of Rhineland-Palatinate, herds were identified that were likely to have a Neospora caninum sero-prevalence [ges ]10% by using a bulk milk ELISA. Individual herd data were obtained by a questionnaire. Univariate logistic regression showed that bulk milk positive farms had a significantly higher chance to report an increased abortion rate than negative farms (PWald<0·1). The chance to have a bulk milk positive herd increased with the minimum number of years a farm had reported an increased abortion rate (PWald<0·1). Questionnaire data, population and dog density as well as climatic data specific for the farm localization were used to identify potential risk factors for a herd to have acquired N. caninum infections. Within an optimized multiple logistic regression model ‘Number of farm dogs’, ‘Herd size’, and factors related to the municipality the farm was localized, i.e. ‘Mean temperature in July’, and ‘Dog density’ were significant risk factors (PWald<0·1). The present study underlines the role farm dogs have in the epidemiology of neosporosis. In addition, it suggests that the risk a herd has to acquire N. caninum infections is also associated with factors related to the farm location, i.e. factors that are largely out of the control of farmers.
A total of ten Heptranchias perlo, eight Deania histricosa, two D. calcea, and two D. profundorum from the Great Meteor Bank, central East Atlantic, were studied for cestodes. The elasmobranchs were caught using bottom trawl or long-lines during September 1998 in 298–1075 m water depth. Seven different cestode species were found: Tentacularia coryphaenae, Deanicola minor, D. protentus, Grillotia meteori sp. nov., Grillotia cf. microthrix (Trypanorhyncha), Crossobothrium dohrnii, and Crossobothrium sp. (Tetraphyllidea). T. coryphaenae occurred encapsulated in the stomach wall and all other species were found within the host intestine. G. meteori sp. nov. and G. cf. microthrix additionally infested the musculature as well as the stomach and intestinal wall. D. profundorum harboured five different cestode species and D. histricosa, H. perlo, and D. calcea were infested with four, three and two species, respectively. With 332 and 181 specimens, D. minor and G. cf. microthrix were the most abundant cestodes. Grillotia meteori sp. nov., Crossobothrium sp., and C. dohrnii were host specific for Deania profundorum, D. histricosa and H. perlo, respectively. The other species were found in more than one elasmobranch, with Deanicola minor and D. protentus restricted to Deania sp. Most parasites are recorded for the first time from the central East Atlantic around the Great Meteor Bank.
A model of functional elements critical for replication
and infectivity of the potato spindle tuber viroid (PSTVd)
was proposed earlier: a thermodynamically metastable structure
containing a specific hairpin (HP II) in the (−)-strand
replication intermediate is essential for template activity
during (+)-strand synthesis. We present here a detailed
kinetic analysis on how PSTVd (−)-strands fold during
synthesis by sequential folding into a variety of metastable
structures that rearrange only slowly into the structure
distribution of the thermodynamic equilibrium. Synthesis
of PSTVd (−)-strands was performed by T7-RNA-polymerase;
the rate of synthesis was varied by altering the concentration
of nucleoside triphosphates to mimic the in vivo synthesis
rate of DNA-dependent RNA polymerase II. With dependence
on rate and duration of the synthesis, the structure distributions
were analyzed by temperature-gradient gel electrophoresis
(TGGE). Metastable structures are generated preferentially
at low transcription rates—similar to in vivo rates—or
at short transcription times at higher rates. Higher transcription
rates or longer transcription times lead to metastable
structures in low or undetectable amounts. Instead different
structures do gradually appear having a more rod-like shape
and higher thermodynamic stability, and the thermodynamically
optimal rod-like structure dominates finally. It is concluded
that viroids are able to use metastable as well as stable
structures for their biological functions.
Due to the lack of effective gettering, gate oxide on thin-film-silicon-on-insulator (TFSOI) substrates is much more sensitive than its bulk Si counterpart to process damage during device fabrication, especially prior to gate oxide growth. Presented in this paper as a typical example is the severe oxide degradation caused by PMOS threshold-voltage implant. Several approaches to circumvent this problem are explored, such as Vt implant without sacrificial oxide (sacox), low temperature anneal before sacox removal, or implementation of lateral gettering. As a result of these efforts, a significant improvement in gate oxide integrity is achieved with increased oxide breakdown voltages and charge-to-breakdowns, as well as a reduction in oxide charge trapping. This work also demonstrates the feasibility of achieving bulk-comparable gate oxide on TFSOI substrates.