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Consistent equations for turbulent open-channel flows on a smooth bottom are derived using a turbulence model of mixing length and an asymptotic expansion in two layers. A shallow-water scaling is used in an upper – or external – layer and a viscous scaling is used in a thin viscous – or internal – layer close to the bottom wall. A matching procedure is used to connect both expansions in an overlap domain. Depth-averaged equations are then obtained in the approximation of weakly sheared flows which is rigorously justified. We show that the Saint-Venant equations with a negligible deviation from a flat velocity profile and with a friction law are a consistent set of equations at a certain level of approximation. The obtained friction law is of the Kármán–Prandtl type and successfully compared to relevant experiments of the literature. At a higher precision level, a consistent three-equation model is obtained with the mathematical structure of the Euler equations of compressible fluids with relaxation source terms. This new set of equations includes shearing effects and adds corrective terms to the Saint-Venant model. At this level of approximation, energy and momentum resistances are clearly distinguished. Several applications of this new model that pertains to the hydraulics of open-channel flows are presented including the computation of backwater curves and the numerical resolution of the growing and breaking of roll waves.
The improvement in porcine embryo preservation and non-surgical embryo transfer (ET) procedures achieved in recent years represents essential progress for the practical use of ET in the pig industry. This study aimed to evaluate the effects of parity, weaning-to-estrus interval (WEI) and season on reproductive and embryonic parameters at day 6 after insemination of donor sows superovulated after weaning. The selection of donor sows was based on their reproductive history, body condition and parity. The effects of parity at weaning (2 to 3, 4 to 5 or 6 to 7 litters), season (fall, winter and spring), and WEI (estrus within 3 to 4 days), and their interactions on the number of corpus luteum, cysts in sows with cysts, number and quality of viable and transferable embryos, embryo developmental stage and recovery and fertilization rates were evaluated using linear mixed effects models. The analyses showed a lack of significant effects of parity, season, WEI or their interactions on any of the reproductive and embryonic parameters examined. In conclusion, these results demonstrate that fertilization rates and numbers of viable and transferable embryos collected at day 6 of the cycle from superovulated donor sows are not affected by their parity, regardless of the time of the year (from fall to spring) and WEI (3 or 4 days).
The Total Solar Irradiance (TSI), which is the total radiation arriving at Earth's atmosphere from the Sun, is one of the most important forcing of the Earths climate. Measurements of the TSI have been made employing instruments on board several space-based platforms during the last four solar cycles. However, combining these measurements is still challenging due to the degradation of the sensor elements and the long-term stability of the electronics. Here we describe the preliminary efforts to design an absolute radiometer based on the principle of electrical substitution that is under development at Brazilian's National Institute for Space Research (INPE).
We derive a new model for thin viscous liquid films down an inclined plane. With an asymptotic expansion in the long-wave limit, the Navier–Stokes equations and the work–energy theorem are averaged over the fluid depth. This gives three equations for the mass, momentum and energy balance which have the mathematical structure of the Euler equations of compressible fluids with relaxation source terms, diffusive and capillary terms. The three variables of the model are the fluid depth, the average velocity and a third variable called enstrophy, related to the variance of the velocity. The equations are numerically solved by classical schemes which are known to be reliable and robust. The model gives satisfactory results both for the neutral stability curves and for the depth profiles of wavy films produced by a periodical forcing or by a random noise perturbation. The numerical calculations agree fairly well with experimental measurements of Liu & Gollub (Phys. Fluids, vol. 6, 1994, pp. 1702–1712). The calculation of the wall shear stress below the waves indicates a flow reversal at the first depth minimum downstream of the main hump, in agreement with experiments of Tihon et al. (Exp. Fluids, vol. 41, 2006, pp. 79–89).
Information relating the severity of cognitive decline to the fall risk in institutionalized older adults is still scarce. This study aims to identify potential fall risk factors (medications, behavior, motor function, and neuropsychological disturbances) depending on the severity of cognitive impairment in nursing home residents.
A total of 1,167 nursing home residents (mean age 81.44 ± 8.26 years; 66.4% women) participated in the study. According to the MEC, (the Spanish version of the Mini-Mental State Examination) three levels of cognitive impairment were established: mild (20–24) “MCI”, moderate (14–19) “MOCI”, and severe (≤14) “SCI”. Scores above 24 points indicated the absence cognitive impairment (NCI). Information regarding fall history and fall risk during the previous year was collected using standardized questionnaires and tests.
Sixty falls (34%) were registered among NCI participants and 417 (43%) among people with cognitive impairment (MCI: 35%; MOCI: 40%; SCI: 50%). A different fall risk model was observed for MCI, MOCI, SCI, and NCI patients. The results imply that the higher the level of cognitive impairment, the greater the number of falls (F1,481 = 113.852; Sig = 0.015), although the level of significance was not maintained when MOCI and SCI participants were compared. Depression, neuropsychiatric disturbances, autonomy constraints in daily life activity performance, and low functional mobility were factors closely associated with fall risk.
This study provides evidence indicating that fall risk factors do not hold a direct correlation with the level of cognitive impairment among elderly nursing home care residents.
High resolution, high S:N spectra are used to determine the abundances of Fe, Ni, Ca, Al and Si in 25 field dwarfs with −1.2<[Fe/H]< +0.3. We find overabundances for Al, Ca and Si in stars with −1.2<[Fe/H]< −0.5 and solar [Ni/Fe] over the whole studied range.
The last decade has brought about a completely different picture of elliptical galaxies. The once considered completely inert systems have revealed the presence of fair amount of dust, cool and cold gas, and undergoing star formation. The current statistics is that 80% of elliptical galaxies have detectable cool gas components, and as many as 60% have ionized gas (Knapp et al. 1989, Goudfrooij et al. 1994). Several single-dish CO surveys have been reported in the literature, allowing the deduction of several general properties of the molecular gas in early-type galaxies (Sage & Wrobel 1989, Lees et al. 1991, Wiklind et al. 1995).
Ammonia was searched in the direction of 46 sources placed in the southern hemisphere where H2CO or H2O was detected previously. Observations were carried out at Itapetinga Radio Observatory, Atibaia, Brazil using a 13.7 m paraboloid. The receiver used for these observations had a K-band ruby travelling wave maser as a preamplifier and the system temperature ranged from 250 to 300K. All sources were observed at least twice, each observation lasting for 30 minutes. The filter bank used consisted of 47 contiguous channels with 100 kHz bandwidth. Results are presented on Table 1 — Positive results and Table 2 — Negative results.
We calculated water vapor conductance (a product of eggshell porosity) from the first definitively identified sauropod egg (Megaloolithus patagonicus) from the Auca Mahuevo locality in Argentina. We then compared the results with those from M. siruguei (an egg type long associated with sauropod dinosaurs) from the Pinyes locality in Spain. The 14-cm Auca Mahuevo egg has a thinner eggshell and 47 times fewer pores than the 22-cm M. siruguei specimen. The resulting water vapor conductance (GH2O) of the titanosaur and M. siruguei eggs is 341 and 3979 mg H2O day−1 Torr−1, respectively; these values are two and ten times greater than in avian eggs of comparable size, but lower than in eggs of most modern reptiles. Clutches from Auca Mahuevo typically contain 20–40 eggs; in contrast, M. siruguei clutches from the Pinyes site average nine eggs. The GH2O of M. siruguei exceeds that of the Argentine egg by an order of magnitude, supporting previous inferences of egg burial. The GH2O of the Argentine titanosaur egg closely approximates that of Troodon and some oviraptorid eggs, previously calculated as equal to or two times greater than, respectively, the GH2O of avian eggs of similar size. Higher embryonic growth rates (relative to modern reptiles), especially in some dinosaurs with large clutch mass, may have required incubation in a more open environment, where water conservation represented a more critical factor than in a buried clutch. The lower GH2O calculated for the two megaloolithid eggs is consistent with previous interpretations of nesting mode that are based on site taphonomy and nesting traces. This study indicates that at least some dinosaurs did not fully bury their eggs.
I deficiency is still a worldwide public health problem, with children being especially vulnerable. No nationwide study had been conducted to assess the I status of Spanish children, and thus an observational, multicentre and cross-sectional study was conducted in Spain to assess the I status and thyroid function in schoolchildren aged 6–7 years. The median urinary I (UI) and thyroid-stimulating hormone (TSH) levels in whole blood were used to assess the I status and thyroid function, respectively. A FFQ was used to determine the consumption of I-rich foods. A total of 1981 schoolchildren (52 % male) were included. The median UI was 173 μg/l, and 17·9 % of children showed UI<100 μg/l. The median UI was higher in males (180·8 v. 153·6 μg/l; P<0·001). Iodised salt (IS) intake at home was 69·8 %. IS consumption and intakes of ≥2 glasses of milk or 1 cup of yogurt/d were associated with significantly higher median UI. Median TSH was 0·90 mU/l and was higher in females (0·98 v. 0·83; P<0·001). In total, 0·5 % of children had known hypothyroidism (derived from the questionnaire) and 7·6 % had TSH levels above reference values. Median TSH was higher in schoolchildren with family history of hypothyroidism. I intake was adequate in Spanish schoolchildren. However, no correlation was found between TSH and median UI in any geographical area. The prevalence of TSH above reference values was high and its association with thyroid autoimmunity should be determined. Further assessment of thyroid autoimmunity in Spanish schoolchildren is desirable.
Depression is one of the most prevalent mental illnesses worldwide and a leading cause of disability, especially in the setting of treatment resistance. In recent years, repetitive transcranial magnetic stimulation (rTMS) has emerged as a promising alternative strategy for treatment-resistant depression and its clinical efficacy has been investigated intensively across the world. However, the underlying neurobiological mechanisms of the antidepressant effect of rTMS are still not fully understood. This review aims to systematically synthesize the literature on the neurobiological mechanisms of treatment response to rTMS in patients with depression. Medline (1996–2014), Embase (1980–2014) and PsycINFO (1806–2014) were searched under set terms. Three authors reviewed each article and came to consensus on the inclusion and exclusion criteria. All eligible studies were reviewed, duplicates were removed, and data were extracted individually. Of 1647 articles identified, 66 studies met both inclusion and exclusion criteria. rTMS affects various biological factors that can be measured by current biological techniques. Although a number of studies have explored the neurobiological mechanisms of rTMS, a large variety of rTMS protocols and parameters limits the ability to synthesize these findings into a coherent understanding. However, a convergence of findings suggest that rTMS exerts its therapeutic effects by altering levels of various neurochemicals, electrophysiology as well as blood flow and activity in the brain in a frequency-dependent manner. More research is needed to delineate the neurobiological mechanisms of the antidepressant effect of rTMS. The incorporation of biological assessments into future rTMS clinical trials will help in this regard.
From September 2000 to September 2001 the concentration of chlorophyll a, and the abundance and composition of the phytoplanktonic community was studied in a neritic station of the Mallorca Channel (Western Mediterranean). Sampling was performed approximately every 12 days. Chlorophyll a concentration and phytoplankton abundance reached maxima of 1.79 μg L−l and 352 cells mL−1, respectively. It was a relatively productive period, as a result of the high convective mixing in winter and the prevalence of northern waters during most of the cycle. Phytoplankton proliferations (chlorophyll a concentration >1 mg L−1) were detected in January, February, March and June. Those blooms mainly happened under the influence of northern waters, with the exception of the February proliferation, when mixing conditions were found. During bloom conditions it highlights the presence of coccolithophores as proliferation precursors. During no-bloom situations the phytoplankton community was mainly constituted by nanoplanktonic flagellated forms. The Winter Mixing period was dominated by different groups of nanoflagellates, including coccolithophores, undetermined flagellates and dinoflagellates. However, in the most oligotrophic conditions (from April until November) dinoflagellates were clearly dominant, except in the DCM in summer where diatoms prevailed.
We introduce the main characteristics of the chemistry system in the ABL. As with the dynamics, we explain the equations that govern the evolution of chemical species, emphasizing in particular their physical and chemical contributions to the diurnal variability of the reactive species, and providing a framework to understand and quantify how dynamic processes interact with the atmospheric reactivity.
Several hundreds of species and reactions characterize the chemistry of the atmospheric boundary layer. As a buffer layer between the surface and the free troposphere, the ABL integrates the emission of chemically active species driven by soil processes or vegetation dynamics as well as their removal by dry and wet deposition processes. Within the dynamically evolving ABL upper region, air entrainment introduces air masses that may either enrich or dilute the chemically reactive species. The presence of ultraviolet radiation and turbulent mixing produces the right conditions for chemical transformations, turning the ABL into a dynamic reaction chamber in which secondary compounds are produced.
A useful method to classify the reactants is to relate them to the dynamic processes by defining the characteristic time-scales of reactions. Figure 3.1 shows some of the most relevant atmospheric components that are active in the lower troposphere. The diagram classifies them as a function of their characteristic reaction speeds and their horizontal spatial variability. This enables us to identify very rapid reactive species (radicals) whose time-scales are similar to those of the fast turbulent motions (<100 s). Particular attention should be paid to the hydroxyl radical (OH) because of its prominent role in oxidizing important hydrocarbon compounds such as methane (CH4), carbon monoxide (CO), and isoprene (C5H8). OH is therefore called the ‘atmospheric cleansing’ agent.
Important species such as O3 and isoprene react on a chemistry time-scale that is similar to the turbulent mixing under diurnal conditions (τ ≈ 15–30 minutes).
Buffering the free atmospheric conditions from the soil-vegetation properties, the atmospheric boundary layer (ABL) is the region in which the wind, temperature, moisture, and atmospheric constituents change from the large atmospheric scales to the biosphere conditions. Over land, the ABL is characterized by a strong diurnal variability (daylight hours) that presents a challenge to modelling studies and observational interpretation. The first purpose of this book is to introduce the reader systematically to the most important biogeochemical and physical processes that take place in the ABL. A flexible user-friendly model of these processes called Chemistry Land-surface Atmosphere Soil Slab (CLASS) was developed to enable the reader interactively and independently to investigate the behaviour of the diurnal ABL over land. Our second aim is to enable the reader to discover freely the interactions and couplings that occur between the atmosphere and land, and to determine their impact on cloud formation, changes in greenhouse gas concentrations, and atmospheric chemistry. To this end, we decided to represent the main fundamental processes in the atmosphere-biosphere system, while retaining the essential components of the physical and biogeochemical processes involved. We have therefore attempted to move beyond individual disciplines to investigate their mutual interrelationships and feedback, laying special emphasis on the conceptualization of the problem. Finally, the interactivity and modular character of the book will make it very useful as a means of interpreting measurements made during experimental campaigns and deepening our understanding of more complex large-scale biogeochemical atmospheric models.