Uniform Temporal Distribution Research Articles

Environmental and spatial factors play different roles in phytoplankton community assembly in different hydrological seasons in Lake Wuchang, China

Lake phytoplankton communities are affected by environmental and spatial factors. We studied the relative importance of environmental and spatial factors on the phytoplankton community assembly in Lake Wuchang across three hydrological seasons, which were divided into dry (December to March), normal (April to June, October to November) and wet seasons (July to September) based on the water level and depth. Spatial and temporal patterns of environmental factors and phytoplankton community composition and diversity were studied using Kruskal–Wallis test, Wilcoxon test and NMDS. CCA, Mantel and partial Mantel tests, and PLS-PM were used to investigate the effects of environmental and spatial factors on phytoplankton community characteristics. Results showed that phytoplankton assemblages at the eight study sites were composed of totally 244 species belonging to 9 phyla, which changed from Bacillariophyta and Chlorophyta to Cyanophyta across the whole hydrological period. There was significantly higher abundance and biomass in the normal and wet seasons than that in the dry season. Phytoplankton alpha diversity exhibited uniform temporal distribution patterns with higher values in the dry season than in the normal and wet seasons. The Mantel and partial Mantel tests revealed that environmental (physicochemical conditions of lake water) and spatial factors (geographic distances among sites) jointly affected the phytoplankton community structure and beta diversity across the hydrological seasons, while spatial factors were more important in the wet season. Partial least squares path models showed that spatial factors exhibited a significant positive correlation with the phytoplankton diversity with the path coefficients of 0.53 and 0.71 in the normal and wet seasons, respectively. Phytoplankton composition had significant correlation with on phytoplankton diversity with the path coefficient of −0.75 and 0.61 in the normal and wet seasons, respectively. Our findings revealed that both environmental and spatial factors affected the phytoplankton community assembly in Lake Wuchang. Environmental factors played a more important role in the dry season, while spatial factors were more important in the wet season. With the exception of the abiotic factors (environmental and spatial), the impacts of biotic factors on phytoplankton community cannot be ignored. Therefore, it is also necessary to strengthen further research on the top-down control over phytoplankton communities in Lake Wuchang.

Spatial varying and co-occurring future climate changes over a heterogeneous river basin: a multivariate approach

Abstract This study explored co-occurring climate-scale changes across the physioclimatically heterogeneous Tapi River basin (TRB) for baseline (1991–2020) and future periods (2021–2100). We used a novel multivariate framework comprising multi-model ensembles of bias-corrected rainfall and temperature from five global climate models (CMIP-5), 12 climate indices (six for each variable), and principal component analysis (PCA). The univariate assessment showed statistically significant warming of 1.1–1.8 °C (1.5–4.0 °C) under RCP-4.5 (RCP-8.5) scenarios. The Middle Tapi basin showed a substantial shift towards a wetter climate regime in the future. The multivariate assessment of spatially varying climate indices resulted in four significant principal components (PCs). The relative evaluation of these PCs showed that nearly 41.6% (47.0%) of the TRB is vulnerable to the transition of the current climatic patterns to the dry–warm (wet–warm) regime under RCP-8.5 (RCP-4.5) in the near (distant) future. On the optimistic side, under RCP-4.5 and RCP-8.5, 53.0% and 69.8% of the TRB displayed signs of uniform temporal distribution with wet rainfall regimes and profound warming towards the end of the 21st century, respectively. The study outcomes would help to devise policies for regional sustainability and adopt mitigation measures to enhance resiliency in a changing climate.

Temporal and Microbiological Analysis of Cardiac Implantable Electrical Device Infections - A Retrospective Study.

Background: Although the causative pathogens in cardiac implantable electronic device (CIED) infections are well known, the relationship between time after implantation and infection patterns has not been sufficiently investigated. This study investigated the microbiology and onset of CIED infections according to infection patterns.Methods and Results: This retrospective study included 97 patients who underwent CIED removal due to device-related infections between April 2009 and December 2018. After device implantation, infections peaked in the first year and declined gradually over 10 years. Most infections (>60%) occurred within 5 years. Staphylococcal infections, the predominant form of CIED infections, occurred throughout the study period. CIED infections were categorized as systemic (SI; n=26) or local (LI; n=71) infections according to clinical presentation, and as CIED pocket-related (PR; n=85) and non-pocket-related (non-PR; n=12) infections according to the pathogenic pathway. The main causative pathogen in SI was Staphylococcus aureus, whereas coagulase-negative staphylococci were mainly related to LI. Both SI and LI peaked in the first year after implantation and then decreased gradually. There was no significant microbiological difference between PR and non-PR infections. PR infections showed the same temporal distribution as the overall cohort. However, non-PR infections exhibited a uniform temporal distribution after the first year.Conclusions: The severity of CIED infections depends on the causative pathogen, whereas their temporal distribution is affected by the microbiological intrusion pathway.

Equine Activity Time Budgets: The Effect of Housing and Management Conditions on Geriatric Horses and Horses with Chronic Orthopaedic Disease.

Simple SummaryHousing and management conditions strongly influence the health, welfare and activity behaviour of horses. To improve horses’ living conditions, it is necessary to establish objective and quantifiable measures that allow for a comparison between environmental living conditions and of how horses of different ages and health statuses are influenced by these environmental conditions. Thus, the aim of the present study was to record and compare time budgets (=percentage of time spent on specific activities) of old (≥20 years) horses and of horses suffering from chronic orthopaedic disease that are living in different husbandry conditions with an automated tracking device. These horses were found to spend similar percentages of time feeding, resting and moving compared to healthy controls. Horses living on different farms and with different turn-out conditions differed in their time budgets. Horses living in open-air group housing on a paddock had less pronounced peaks in their feeding and movement activities over time compared to horses living in more restricted husbandry systems. The findings of the study can help to identify potential improvements of husbandry conditions of horses to maximise their health and welfare.Housing and management conditions strongly influence the health, welfare and behaviour of horses. Consequently, objective and quantifiable comparisons between domestic environments and their influence on different equine demographics are needed to establish evidence-based criteria to assess and optimize horse welfare. Therefore, the present study aimed to measure and compare the time budgets (=percentage of time spent on specific activities) of horses with chronic orthopaedic disease and geriatric (≥20 years) horses living in different husbandry systems using an automated tracking device. Horses spent 42% (range 38.3–44.8%) of their day eating, 39% (range 36.87–44.9%) resting, and 19% (range 17–20.4%) in movement, demonstrating that geriatric horses and horses suffering from chronic orthopaedic disease can exhibit behaviour time budgets equivalent to healthy controls. Time budget analysis revealed significant differences between farms, turn-out conditions and time of day, and could identify potential areas for improvement. Horses living in open-air group housing on a paddock had a more uniform temporal distribution of feeding and movement activities with less pronounced peaks compared to horses living in more restricted husbandry systems.

Early Mortality after Radical Radiotherapy in Head and Neck Cancer – A Nationwide Analysis from the Danish Head and Neck Cancer Group (DAHANCA) Database

AimsCurative-intent radiotherapy (RT) or chemoradiation (CRT) of squamous cell carcinoma of the head and neck (HNSCC) produces high survival rates, but is associated with substantial toxicity. However, there are no commonly accepted quality metrics for early mortality in radiation oncology. To assess the applicability of early mortality as a clinical quality indicator, this study investigated the temporal distribution, risk factors and trends of 90- and 180-day overall and non-cancer mortality in a nationwide cohort of HNSCC patients treated with RT/CRT. Materials and methodsInformation on all HNSCC patients treated with curative-intent RT/CRT in Denmark between 2000 and 2017 was obtained from the national Danish Head and Neck Cancer Group clinical database. Deaths in patients with residual or recurrent disease after RT/CRT were classified as cancer-related. Possible risk factors were investigated using logistic regression analysis. ResultsData from 11 419 patients were extracted. In total, 90- and 180-day mortality risks were 3.1% and 7.1%, respectively. There was a uniform temporal distribution of 180-day mortality. In multivariable analysis, increasing age, stage, performance status, earlier treatment year and hypopharyngeal cancer were significantly associated with an increased risk (P < 0.05). Risk factor estimates were comparable for 90- versus 180-day mortality as well as for overall versus non-cancer mortality. Between 2000 and 2017 there was a significant decrease in 180-day mortality, which was driven by a reduction in cancer-related events. ConclusionThe distribution of 180-day overall and non-cancer mortality did not indicate a well-defined early high-risk period. Moreover, risk factor estimates were highly similar across risk periods and groups. Taken together, our findings question the applicability of early mortality as a standard metric for treatment-associated toxicity.

Spatial and temporal variability of daily precipitation concentration in the Sardinia region (Italy)

AbstractRecent studies evidenced that extreme daily rainfall often increases in spite of a decrease of the total rainfall. For this reason, the analysis of daily precipitation concentration is an important issue in climate research and can be useful to evaluate risks linked to extreme rainfall events. In this paper, an analysis of the spatial and temporal variability of the daily precipitation concentration in the Sardinia region, the second largest island in the Mediterranean Sea, has been performed for the period 1922–2011 by applying the Concentration Index. First, the CI has been evaluated at annual and seasonal scale. Then, the coefficient of variation, and the 5th and 95th percentiles of the annual CI values were calculated and mapped as a set of descriptors of variability and extreme characterization of precipitation concentration across the study area. Finally, in order to evaluate the temporal evolution of the CI, a trend analysis has been also performed using the Mann–Kendall test. Results show CI values ranging from a minimum of 0.477 to a maximum of 0.723. Spatially, the region can be divided in two parts with opposite behaviours: the western side characterized by a more uniform temporal distribution of rainfall intensity and the eastern side with the most critical intensity and aggressiveness of rainfall. From a seasonal point of view, this spatial gradient was evidenced in winter, spring and autumn while summer showed a more homogeneous spatial distribution of CI. The spatial distribution of the coefficient of variation did not show any spatial gradient between the two sides of the region, both at annual and seasonal scale. As regards the trend analysis, a marked positive trend of the CI has been detected, thus indicating a tendency towards more intense and aggressive rainfall. Copyright © 2019 John Wiley &amp; Sons, Ltd.

Spatial and temporal distribution of Gymnorhamphichthys rondoni (Gymnotiformes: Rhamphichthyidae) in a long-term study of an Amazonian terra firme stream, Leticia - Colombia

ABSTRACT Weakly electric fishes continually emit electric organ discharges (EOD) as a means of communication and localization of objects in their surroundings. Depending on water conductivity, the amplitude of the electric field generated is known to increase with decreases in electrical conductivity of the water. In Amazonian terra firme streams, water conductivity is extremely low and fluctuates constantly due to local and regional rains. In this context, the space between freely moving weakly electric fishes may be expected to decrease, on average, with an increase in water conductivity. To test this hypothesis, we recorded the positions at rest of the sand-dwelling fish Gymnorhamphichthys rondoni in a terra firme stream for several days in alternating months, over two years. Based on daily nearest neighbor distances among individual fish in a grid, we found a uniform temporal distribution pattern (which was not affected by water conductivity) indicative of site fidelity. Here we highlight the role of other factors that could influence resting site fidelity.

Effects of ultrasound pulse parameters on cavitation properties of flowing microbubbles under physiologically relevant conditions

Acoustic cavitation from ultrasound-driven microbubbles can induce diverse bioeffects that are useful in clinical therapy. However, lack of control over the cavitation activity of flowing microbubbles results in unwanted treatment regions in the targeted tissue, which influences the therapeutic efficacy and bio-safety. The aim of this study is to understand the relationship between the ultrasound pulse parameters and cavitation properties of flowing microbubbles, including the type (and transition between types), threshold, intensity and temporal distribution of cavitation. An in vitro physiological-flow phantom was fabricated, in which the microbubbles had a constant velocity, and were sonicated to a 1-MHz focused transducer at a wide range of peak negative pressures (PNPs) (0.10–1.28 MPa), pulse repetition frequencies (PRFs) (1–200 Hz) and pulse lengths (PLs) (10–400 μs). The signals from the flowing bubbles were passively detected by another 7.5-MHz plane transducer. From detailed time- and frequency-domain analysis, we found 1). The occurrence of stable cavitation (SC) and inertial cavitation (IC) depended on PNP and PL when the PRF was below a critical value (PRF threshold) that related to the fluid velocity and PNP full width at half maximum diameter of the transducer. 2) Below the PRF threshold, the PL had no influence on the temporal distribution of SC intensity; however, above the PRF threshold, the SC properties depended on the PL because of acoustically-driven diffusion. Specifically, at shorter PLs, the SC intensity had a uniform temporal distribution and was independent of the PRF; at longer PLs, the SC intensity correlated negatively with the PRF. 3) Below the PRF threshold, the IC properties were independent of the PRF. Increasing the PRF above the PRF threshold caused the IC intensity to decrease with a non-uniform temporal distribution. These results indicate that the fluid velocity and a pulsed acoustic field influence the number and properties of the replenished bubbles into the targeted region, resulting in the change of cavitation properties. In future therapeutic applications, the physiological fluid conditions must be taken into consideration to design reasonable pulse parameters and achieve desirable cavitation properties.

Características das Frentes Frias Causadoras de Chuvas Intensas no Leste de Santa Catarina

Resumo O presente trabalho analisa as características principais das frentes frias causadoras de chuvas intensas no litoral do Estado de Santa Catarina, com a finalidade de melhorar o conhecimento e a previsão desse tipo de situação. Para isso, foi feita uma climatologia sinótica das frentes frias, utilizando reanálises CFSR do NCEP e dados de precipitação do CPTEC/INPE no período 1998-2010, a partir dos quais foram separados 5% das frentes frias mais chuvosas da série. Os resultados mostram que as frentes frias que provocam chuvas mais volumosas ocorrem ao longo de todo o ano, associadas à penetração de cavados frios, intensos e pouco baroclínicos nos níveis médios e altos da atmosfera. A lenta evolução da situação meteorológica permite a intensificação de um cavado na baixa troposfera, que provoca a gradativa intensificação da instabilidade termodinâmica sobre o leste de Santa Catarina, através da advecção de calor e umidade desde a Amazônia. A frente fria que dispara a precipitação apresenta forte inclinação nos baixos níveis e lento deslocamento. Em geral, a situação meteorológica apresenta poucas variações sazonais e pode ser identificada, em média, com pelo menos 48 h de antecedência.

Beam Dynamics Investigation for the Compact Seeded THz-FEL Amplifier

A compact seeded terahertz (THz) free-electron laser (FEL) amplifier is under development at the Institute of Advanced Energy, Kyoto University. The system consists of a 1.6-cell S-band BNL-type photocathode radio frequency (RF) gun, a focusing solenoid magnet, a magnetic bunch compressor, focusing quadrupoles, a short planar undulator and a THz parametric generator for seeding. The accelerator system will generate a high brightness ultra-short electron bunch injected to the short undulator. Since characteristics of the emitted radiation strongly depend on the electron beam properties, the beam dynamics of the system has been investigated. As the result, the system should be operated at the high accelerating voltage of 80 MV/m to avoid the space-charge effect which causes serious bunch lengthening. The laser with the uniform temporal distribution and the injection phase of 12 degree is suitable for the bunch compression in the chicane. This condition provides the electron beam injected to the undulator with the peak current of more than 300 A and the FWHM bunch length of 0.36 ps at the bunch charge of 200 pC.

S-brane to thermal non-singular string cosmology

We present a new class of non-singular string cosmologies in d spacetime dimensions. At very early times, τ ≪ τc, the Universe is described by a flat σ-model metric, a constant maximal temperature Tc and super-weak string interactions, gstr ≪ 1. During the evolution, the metric remains flat up to τc, while the string coupling grows and reaches a critical value g*str at τc. This phase is characterized by a uniform temporal distribution of spacelike branes. At later times, τ > τc, the Universe enters in a new phase of expansion, with radiation. The string coupling decreases due to the dilaton motion and asymptotes to a constant for τ ≫ τc. Throughout the evolution, the string coupling remains smaller than g*str. In the Einstein frame, the cosmologies describe bouncing Universes, where two distinct phases are connected at τc. In the initial contracting phase, the evolution of the scale factor is identical to that of a negatively curved Universe filled with radiation. At later times, the Universe enters an expanding thermal phase with a running dilaton. Explicit examples are presented in a large class of thermal (4, 0) type II superstring vacua, with non-trivial ‘gravito-magnetic’ fluxes.

Effects of rainwater harvesting on centralized urban water supply systems

The potential effect of widespread rainwater harvesting practices on mains water demand and quality management are investigated for three different types of urban areas characterized by different roof area to water demand ratios. Two rainfall patterns are considered with similar average annual depths but very different temporal distributions. Supply reliability and the extent of reliance on the public distribution system are identified as suitable performance indicators for mains water infrastructure. A uniform temporal distribution of rainfall in an oceanic climate like that of Dinard, Northern France, yielded supply reliabilities close to 100% for reasonable tank sizes (0.065 m3/m2 of roof area in Dinard compared with 0.262 m3/m2 in Nice with a RWSO of 30% for a detached house). However, the collection and use of rainfall results in a permanent decrease in mains water demand leading to an increase in water age in the distribution network. Investigations carried on a real network showed that water age is greatly affected when rainwater supplies more than 30% of the overall water demand. In urban water utilities planning, rainwater supply systems may however be profitable for the community if they enable the deferment of requirements for new mains water infrastructure.

The temporal organisation of the feeding behaviour of four species of wallaby: examining chronobiological and homeostatic influences

We studied the temporal distribution of feeding events of tammar wallabies, parma wallabies, brush-tailed rock-wallabies and swamp wallabies by infrared video-recording of captive animals maintained in a 12 : 12 light : dark cycle with constant temperature, and by radio-microphone surveillance of free-ranging animals on Kawau Island, New Zealand. Analyses of mean time spent feeding per 20-min period for tammar and parma wallabies showed significant circadian variation in both captive and free-ranging animals but not in captive or free-ranging brush-tailed rock wallabies or swamp wallabies. While there was no significant difference in the extent of circadian variation of feeding rate between tammar and parma wallabies there were significant differences according to the type of food being fed. Thus, circadian variation in feeding rate was greater in both species when standing sward was fed. None of the survivorship curves of the interfeed intervals of either captive or free-ranging animals showed a discontinuity suggestive of organisation of feed events into meals. There were bicrepuscular peaks of feed-event density in both captive and free-ranging tammar and parma wallabies. There was a similar bicrepuscular distribution of feed-event density in free-ranging brush-tailed rock-wallabies but a more uniform temporal distribution of this parameter in captive specimens. There was a more uniform circadian distribution of feed-event density in a single captive and a single free-ranging swamp wallaby. Thus the circadian incidence of the feeding events of tammar and parma wallabies were more resistant to changes in the incidence of stochastic environmental variables such as predation whereas those of bush-tailed rock-wallabies and swamp wallabies were more susceptible to changes in these stimuli.

Fire Incident Characteristics Of A Densely Populated Oriental Urban City

Hong Kong is a small but densely populated oriental city with limited natural resources. The fire engineering approach to formulating fire safety strategies for buildings requires information on the number and characteristics of fires that occurred in different types of buildings. In this paper, fire incident statistical data collected by the Hong Kong Fire Services Department for years 1991 to 2001 is analysed. It is found that residential buildings constituted 75% of the total number of building fires, however fire risk appears to be the highest in buildings classified as Places of Public Assembly, using the number of fatalities and injuries per fire as an indicator. The statistical data seems to imply that quality of maintenance of equipment and power supply in privately built shopping arcades, commercial premises and residential buildings is lower than the same buildings owned by the government. Apart from the fire engineering perspective, the fire statistics seems to also reflect to some degree the social make-up and work pattern of the society of Hong Kong, for example, more fires due to carelessness occurred in buildings with lesser educated occupants, and relatively uniform temporal distribution of fires in most parts of the day in private commercial buildings due to significant amount of overtime and overnight work.