scholarly journals Estimation of atmospheric particle formation rates through an analytical formula: Validation and application in Hyytiälä and Puijo, Finland

2017 ◽  
Author(s):  
Elham Baranizadeh ◽  
Tuomo Nieminen ◽  
Taina Yli-Juuti ◽  
Markku Kulmala ◽  
Tuukka Petäjä ◽  
...  
Keyword(s):  
Time Lag ◽  
Analytical Formula ◽  
Particle Formation ◽  
Coagulation Rate ◽  
Atmospheric Particle ◽  
Size Dependent ◽  
The Mean ◽  
Condensational Growth ◽  
Measured Size Distribution ◽  
Daily Time

Abstract. The formation rates of 3-nm particles were estimated at SMEAR IV, Puijo (Finland) where the continuous measurements extend only down to 7 nm in diameter. We extrapolated the formation rates at 7 nm (J7) down to 3 nm (J3) based on an approximate solution to the aerosol general dynamic equation, assuming a constant condensational growth rate, a power-law size dependent scavenging rate and negligible self-coagulation rate for the nucleation mode particles. To evaluate our method, we first applied it to new-particle formation (NPF) events in Hyytiälä (Finland), which extend down to 3 nm, and, therefore, J3 and J7 can be determined directly from the measured size distribution evolution. The Hyytiälä results show that the estimated daily mean J3 slightly overestimate the observed mean J3, but a promising 84 % of the estimated J3 are within a factor of 2 from the measured ones. However, when considering detailed daily time evolution, the agreement is typically poor presumably due to uncertainties in estimated growth rates which are required in order to calculate the time-lag between formation of 3-nm and 7-nm particles. At Puijo, the mean and median J7 for clear NPF days during April 2007–December 2015 were 0.23 and 0.07 cm−3 s−1, respectively, while the extrapolated mean and median J3 were 0.47 and 0.13 cm−3 s−1, respectively.

scholarly journals Estimation of atmospheric particle formation rates through an analytical formula: validation and application in Hyytiälä and Puijo, Finland

2017 ◽  
Vol 17 (21) ◽  
pp. 13361-13371
Author(s):  
Elham Baranizadeh ◽  
Tuomo Nieminen ◽  
Taina Yli-Juuti ◽  
Markku Kulmala ◽  
Tuukka Petäjä ◽  
...  
Keyword(s):  
Time Lag ◽  
Analytical Formula ◽  
Particle Formation ◽  
Coagulation Rate ◽  
Atmospheric Particle ◽  
Size Dependent ◽  
The Mean ◽  
Condensational Growth ◽  
Measured Size Distribution ◽  
Daily Time

Abstract. The formation rates of 3 nm particles were estimated at SMEAR IV, Puijo (Finland), where the continuous measurements extend only down to 7 nm in diameter. We extrapolated the formation rates at 7 nm (J7) down to 3 nm (J3) based on an approximate solution to the aerosol general dynamic equation, assuming a constant condensational growth rate, a power-law size-dependent scavenging rate, and negligible self-coagulation rate for the nucleation mode particles. To evaluate our method, we first applied it to new particle formation (NPF) events in Hyytiälä (Finland), which extend down to 3 nm, and, therefore, J3 and J7 can be determined directly from the measured size distribution evolution. The Hyytiälä results show that the estimated daily mean J3 values slightly overestimate the observed mean J3, but a promising 91 % of the estimated J3 values are within a factor of 2 from the measured ones. However, when considering detailed daily time evolution, the agreement is not as good due to fluctuations in data as well as uncertainties in estimated growth rates, which are required in order to calculate the time lag between formation of 3 and 7 nm particles. At Puijo, the mean J7 for clear NPF days during April 2007–December 2015 was 0.44 cm−3 s−1, while the extrapolated mean J3 was 0.61 cm−3 s−1.

scholarly journals Observation of aerosol size distribution and new particle formation at a mountain site in subtropical Hong Kong

2012 ◽  
Vol 12 (5) ◽  
pp. 12119-12162 ◽  
Author(s):  
H. Guo ◽  
D. W. Wang ◽  
Z. H. Ling ◽  
C. K. Chan ◽  
X. H. Yao
Keyword(s):  
Hong Kong ◽  
Formation Rate ◽  
Particle Formation ◽  
Aerosol Size Distribution ◽  
New Particle Formation ◽  
Average Growth ◽  
Nucleation Mode ◽  
Atmospheric Particle ◽  
The Mean ◽  
Linear Correlations

Abstract. In order to investigate the atmospheric particle formation and growth processes, and to quantify the particle number (PN) concentration and size distributions in Hong Kong, a three-month intensive field measurement was conducted from September to November in 2010 near the mountain summit of Tai Mo Shan, a suburban site approximately the geographical centre of the New Territories in Hong Kong. The mean total number concentration in the size range of 5.5–350 nm was 7.86 ± 0.66 × 103 cm−3 (mean ± 95% confidence interval), with a maximum value in November. New particle formation (NPF) events were observed on 12 out of 35 days in October/November 2010 with the formation rate from 0.29 to 4.53 cm−3 s−1, and the average growth rates from 1.53 to 9.44 nm h−1. The events usually began at 10:00 ~ 11:00 local time characterized by the occurrence of a nucleation mode with a peak diameter of 6 ~ 10 nm. The observed linear or non-linear correlations between nucleation mode PN concentration (5.5–10 nm) and ozone, volatile organic compounds (VOCs) and/or (UV × SO2) suggested critical roles of sulfuric acid and biogenic VOCs (e.g. isoprene, α-pinene and β-pinene) in the NPF events.

scholarly journals Daily Time Use by Activity of Community-Dwelling Older Koreans: Focus on Health Management

2021 ◽  
Vol 18 (4) ◽  
pp. 1688
Author(s):  
Hana Ko
Keyword(s):  
Older Adults ◽  
Time Use ◽  
Health Management ◽  
Subjective Evaluation ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Community Dwelling ◽  
Senior Center ◽  
The Mean ◽  
Daily Time

This study aimed to examine the daily time use by activity and identified factors related to health management time (HMT) use among 195 older adults (mean age = 77.5, SD = 6.28 years; 70.8% women) attending a Korean senior center. Descriptive statistics were analyzed and gamma regression analyses were performed. Participants used the most time on rest, followed by leisure, health management, daily living activities, and work. The mean duration of HMT was 205.38 min/day. The mean score for the subjective evaluation of health management (SEHM) was 13.62 and the importance score for SEHM was 4.72. Factors influencing HMT included exercise, number of chronic conditions, fasting blood sugar level, low density lipoprotein level, and cognitive function. HMT and frailty significantly predicted SEHM. HMT interventions focus on promoting exercise and acquiring health information to improve health outcomes among older adults in senior centers.

scholarly journals Assessing Early Heterogeneity in Doubling Times of the COVID-19 Epidemic across Prefectures in Mainland China, January–February, 2020

Epidemiologia ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 95-113 ◽  
Author(s):  
Isaac Chun-Hai Fung ◽  
Xiaolu Zhou ◽  
Chi-Ngai Cheung ◽  
Sylvia K. Ofori ◽  
Kamalich Muniz-Rodriguez ◽  
...  
Keyword(s):  
Regression Models ◽  
Doubling Time ◽  
Metropolitan Areas ◽  
Mainland China ◽  
Linear Regression Models ◽  
Case Count ◽  
Daily Time Series ◽  
The Mean ◽  
Doubling Times ◽  
Daily Time

To describe the geographical heterogeneity of COVID-19 across prefectures in mainland China, we estimated doubling times from daily time series of the cumulative case count between 24 January and 24 February 2020. We analyzed the prefecture-level COVID-19 case burden using linear regression models and used the local Moran’s I to test for spatial autocorrelation and clustering. Four hundred prefectures (~98% population) had at least one COVID-19 case and 39 prefectures had zero cases by 24 February 2020. Excluding Wuhan and those prefectures where there was only one case or none, 76 (17.3% of 439) prefectures had an arithmetic mean of the epidemic doubling time <2 d. Low-population prefectures had a higher per capita cumulative incidence than high-population prefectures during the study period. An increase in population size was associated with a very small reduction in the mean doubling time (−0.012, 95% CI, −0.017, −0.006) where the cumulative case count doubled ≥3 times. Spatial analysis revealed high case count clusters in Hubei and Heilongjiang and fast epidemic growth in several metropolitan areas by mid-February 2020. Prefectures in Hubei and neighboring provinces and several metropolitan areas in coastal and northeastern China experienced rapid growth with cumulative case count doubling multiple times with a small mean doubling time.

Spontaneous Blinks as a Criterion of Visual Fatigue during Prolonged Work on Visual Display Terminals

2001 ◽  
Vol 92 (1) ◽  
pp. 234-250 ◽  
Author(s):  
Kenichi Kaneko ◽  
Kazuyoshi Sakamoto
Keyword(s):  
Time Lag ◽  
Vertical Direction ◽  
Visual Display ◽  
Hard Copy ◽  
Subjective Feeling ◽  
Visual Fatigue ◽  
Work Time ◽  
Mean Values ◽  
Significant Difference ◽  
The Mean

Visual fatigue caused by prolonged work viewing a Visual Display Terminals (VDT) and of work reading a hard-copy were assessed by electromyogram (EMG) waveform and electrooculogram (EOG) waveform in spontaneous blinks as objective criteria, and by questionnaire of subjective feeling, and by task performance. The duration and the amplitude of the EMG of the orbicularis ocular muscle on the right side and the EOG of the vertical direction to the eyelid were measured for 10 subjects who participated in a figure task consisting of the addition of single-digit numbers on a VDT work or a work with a hard-copy. The mean values of the duration and the amplitude of the EMG and the EOG were evaluated by the averaging of 10 waveforms of the spontaneous blinks for all subjects. The time lag from the EMG to the EOG in the process of the generation of spontaneous blinks was also analyzed. These five parameters were evaluated during the work time. The mean values for the duration of the EMG increased gradually during the work time, but the amplitude did not show significant difference between the prework and a work time. There was no significant change of the duration of the EOG, but the mean amplitude of the EOG decreased as the work time progressed, and the time lag significantly extended. The blinks frequency increased relatively when using a VDT. The rate of fluctuation for these parameters was higher during use of a VDT than use of a hard-copy. The time lag at five hours of VDT work was extended by 90% based on the value at the prework. The symptoms of general fatigue and fatigue of the eyes increased linearly during the VDT work for six hours. The results indicated a significant correlation between the objective parameters for the activity of the spontaneous blinks, i.e., duration and amplitude of EMG and EOG, and the time lag between EMG and EOG, and the subjective feeling was recognized in the time course of the task. These experimental results suggested that the parameters regarding the EMG and the EOG for the spontaneous blinks were effective indices for assessing visual fatigue during prolonged VDT work.

Size-Dependent Variation in the Evasive Behaviour of the Bivalve Mollusc Spisula Solidissima

1979 ◽  
Vol 78 (1) ◽  
pp. 59-75
Author(s):  
DAVID J. PRIOR ◽  
ANNE M. SCHNEIDERMAN ◽  
SHARON I. GREENE
Keyword(s):  
Receptive Fields ◽  
Bivalve Mollusc ◽  
Spisula Solidissima ◽  
Visceral Ganglion ◽  
Size Dependent ◽  
Boston University ◽  
Asterias Forbesi ◽  
The Mean ◽  
The Individual ◽  
Tube Feet

1. The evasive jump response of Spisula can be elicited by contact of the siphons with the tube feet of a starfish (Asterias forbesi). 2. The level of responsiveness varies with the size of the individual clam; small clams (2.0-5.0 cm) being very responsive, large clams (12.0-18.0 cm) being totally unresponsive. 3. The cell bodies of touch-sensitive neurones subserving the siphons are located in the visceral ganglion. The mean area of the receptive fields of these neurones in small clams is 33.8 mm2 and in large clams is 9.7 mm2. 4. In small clams the large proportion of the total siphon surface innervated by single touch-sensitive neurones results in considerable overlap of receptive fields. As a result of this overlap, numerous touch-sensitive neurones are activated by a point stimulus. 5. The variation in jump responsiveness of large and small clams is correlated with the size of the receptive fields of touch-sensitive neurones. Note: Present address: Department of Zoology, University of California, Berkeley, CA 04720. Present address: Boston University Marine Program, Woods Hole, MA 02543.

scholarly journals Usage Count: A New Indicator to Detect Research Fronts

2017 ◽  
Vol 2 (1) ◽  
pp. 89-104 ◽  
Author(s):  
Guoqiang Liang ◽  
Haiyan Hou ◽  
Zhigang Hu ◽  
Fu Huang ◽  
Yajie Wang ◽  
...  
Keyword(s):  
Regenerative Medicine ◽  
Citation Count ◽  
Time Lag ◽  
Research Front ◽  
Research Fronts ◽  
The Mean ◽  
New Perspective ◽  
Practical Implications ◽  
Traditional Indicator ◽  
Highly Cited

Abstract Purpose Research fronts build on recent work, but using times cited as a traditional indicator to detect research fronts will inevitably result in a certain time lag. This study attempts to explore the effects of usage count as a new indicator to detect research fronts in shortening the time lag of classic indicators in research fronts detection. Design/methodology/approach An exploratory study was conducted where the new indicator “usage count” was compared to the traditional citation count, “times cited,” in detecting research fronts of the regenerative medicine domain. An initial topic search of the term “regenerative medicine” returned 10,553 records published between 2000 and 2015 in the Web of Science (WoS). We first ranked these records with usage count and times cited, respectively, and selected the top 2,000 records for each. We then performed a co-citation analysis in order to obtain the citing papers of the co-citation clusters as the research fronts. Finally, we compared the average publication year of the citing papers as well as the mean cited year of the co-citation clusters. Findings The citing articles detected by usage count tend to be published more recently compared with times cited within the same research front. Moreover, research fronts detected by usage count tend to be within the last two years, which presents a higher immediacy and real-time feature compared to times cited. There is approximately a three-year time span among the mean cited years (known as “intellectual base”) of all clusters generated by usage count and this figure is about four years in the network of times cited. In comparison to times cited, usage count is a dynamic and instant indicator. Research limitations We are trying to find the cutting-edge research fronts, but those generated based on co-citations may refer to the hot research fronts. The usage count of older highly cited papers was not taken into consideration, because the usage count indicator released by WoS only reflects usage logs after February 2013. Practical implications The article provides a new perspective on using usage count as a new indicator to detect research fronts. Originality/value Usage count can greatly shorten the time lag in research fronts detection, which would be a promising complementary indicator in detection of the latest research fronts.

scholarly journals A model for particle formation and growth in the atmosphere with molecular resolution in size

2002 ◽  
Vol 2 (5) ◽  
pp. 1791-1807 ◽  
Author(s):  
K. E. J. Lehtinen ◽  
M. Kulmala
Keyword(s):  
Growth Rate ◽  
Atmospheric Aerosol ◽  
Aerosol Particles ◽  
Slight Modification ◽  
Particle Formation ◽  
Simulation Methods ◽  
Discrete Method ◽  
Condensational Growth ◽  
Particle Formation And Growth ◽  
Diffusion Problems

Abstract. The formation and growth of atmospheric aerosol particles is considered using an exact discrete method with molecular resolution in size space. The method is immune to numerical diffusion problems that are a nuisance for typical simulation methods using a sectional representation for the particle size distribution. For condensational growth, a slight modification is proposed for the Fuchs-Sutugin expression, which improves the prediction of the growth rate of nano-sized particles by as much as a factor of two. The presented method is applied to particle formation in a Finnish Boreal forest and is shown to capture the essential features of the dynamics quite nicely. Furthermore, it is shown that the growth of the particles is roughly linear, which means that the amount of condensable vapour is constant (of the order 1013 1/m3).

Effets du statut socioéconomique sur l'activité physique d'enfants prépubères

2003 ◽  
Vol 28 (2) ◽  
pp. 190-203 ◽  
Author(s):  
Alexandre Melin ◽  
Philippe Obert ◽  
Pierre Bonnet ◽  
Daniel Courteix
Keyword(s):  
Physical Activity ◽  
Heart Rate ◽  
Socioeconomic Status ◽  
Normal Subjects ◽  
Habitual Physical Activity ◽  
Heart Rate Reserve ◽  
Statut Socioéconomique ◽  
The Mean ◽  
And Gender ◽  
Daily Time

In order to assess possible influences of socioeconomic status and gender on habitual physical activity (HPA) of prepubertal French children, daily heart rate was 24-hr-monitored in 65 normal subjects for 2 days in the same school week. HPA was evaluated as the mean daily time spent at heart rates greater than 140 bpm (tFC > 140), 160 bpm (tFC > 160), 50% (tFC > 50%), and 70% (tFC > 70%) of the heart rate reserve. An effect of socioeconomic status (determined by questionnaire) was found in boys, with HPA being greater in the underprivileged ones (tFC > 140: 51.8 ± 30.1 vs 33.0 ± 14.1 min, p < .05; tFC > 160: 22.7 ± 16.6 vs 11.1 ± 7.4 min, p < .05; tFC > 50%: 61.4 ± 33.5 vs 46.5 ± 17.1 min, p < .06; tFC > 70%: 20.1 ± 15.2 vs 10.6 ± 7.1, p < .05). Boys were more active than girls, but only in the underprivileged group (tFC > 140: 51.8 ± 30.1 vs 32.8 ± 26.0 min, tFC > 160: 22.7 ± 16.6 vs 9.9 ± 8.2 min, p < .05; tFC > 50%: 61.4 ± 33.5 vs 37.4 ± 23.8 min, p < .05; tFC > 70%: 20.1 ± 15.2 vs 8.1 ± 6.3, p < .05). Cultural factors could be involved in these results. Key words: habitual physical activity, heart rate, heart rate meter, gender, energy expenditure

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