Abstract P164: Seasonal patterns of mortality from cardiovascular diseases in Panama.

Circulation ◽  
2012 ◽  
Vol 125 (suppl_10) ◽  
Author(s):  
Jorge A Motta ◽  
Carlos Gordon ◽  
Beatriz Gomez ◽  
Eva Castillo ◽  
Hugo Herrera-Ballesteros

Seasonal patterns of cardiovascular (CV) mortality have been reported in many regions of the world, but mostly in temperate zones. These cycles and seasonal patterns of mortality have been identified by looking at mortality rate series over extended periods of time and by filtering its stochastic components. The reasons for these variations have been attributed to multiple causes. Empirical observations by health care worker have suggested that in Panama there are seasonal changes of CV disease mortality but this phenomenon had not been studied. The speculation is that this may be related to variation in the incidence of respiratory diseases, weather changes or to population activity patterns associated with holidays. Our hypothesis for this study is that in Panama mortality related to CV disease has a seasonal pattern. We compiled from the National Registry of Mortality all deaths that occurred in the country from cardiovascular diseases (n=36,145) and diabetes (n=7,076) for the years 2001–2009. A monthly time series of mortality was calculated and its components were decomposed utilizing moving averages. Elements, like cycle, seasonal occurrence and stochastic components, were separated. We also developed a seasonal index of mortality for these diseases. For the same years, we performed a similar analysis for all deaths attributed to cancer and external causes. Analysis of these mortality series revealed seasonal cycles for total cardiovascular mortality and diabetes mortality. Death from cancer and external causes also showed seasonal cycles. CV mortality and diabetes mortality peaked at the beginning of the third trimester of the year and were lowest during the first trimester. For the month of July, the CV mortality seasonal index showed a score of 108, and an average number of CV deaths of 364. The lowest seasonal index score for CV mortality was 87 in February, with an average number of CV deaths of 296. The cycles observed for cancer and deaths from external causes did not match the cycles observed for CV diseases and diabetes. We conclude that there is a seasonal pattern of CV mortality in Panama. The drivers of these cyclical changes of CV mortality have not yet been identified, but we are evaluating the relationship of acute respiratory illnesses, population activity patterns and weather changes to these seasonal mortality variations.

Crisis ◽  
2014 ◽  
Vol 35 (1) ◽  
pp. 5-9 ◽  
Author(s):  
Daniel Hideki Bando ◽  
Fernando Madalena Volpe

Background: In light of the few reports from intertropical latitudes and their conflicting results, we aimed to replicate and update the investigation of seasonal patterns of suicide occurrences in the city of São Paulo, Brazil. Methods: Data relating to male and female suicides were extracted from the Mortality Information Enhancement Program (PRO-AIM), the official health statistics of the municipality of São Paulo. Seasonality was assessed by studying distribution of suicides over time using cosinor analyses. Results: There were 6,916 registered suicides (76.7% men), with an average of 39.0 ± 7.0 observed suicides per month. For the total sample and for both sexes, cosinor analysis estimated a significant seasonal pattern. For the total sample and for males suicide peaked in November (late spring) with a trough in May–June (late autumn). For females, the estimated peak occurred in January, and the trough in June–July. Conclusions: A seasonal pattern of suicides was found for both males and females, peaking in spring/summer and dipping in fall/winter. The scarcity of reports from intertropical latitudes warrants promoting more studies in this area.


2013 ◽  
Vol 141 (11) ◽  
pp. 2403-2409 ◽  
Author(s):  
Y. H. LU ◽  
H. Z. QIAN ◽  
A. Q. HU ◽  
X. QIN ◽  
Q. W. JIANG ◽  
...  

SUMMARYWe studied seasonal patterns of swine hepatitis E virus (HEV) infection in China. From 2008 to 2011, 4200 swine bile specimens were collected for the detection of HEV RNA. A total of 92/2400 (3·83%) specimens in eastern China and 47/1800 (2·61%) specimens in southwestern China were positive for HEV. Seasonal patterns differing by geographical area were suggested. In eastern China, the major peak of HEV RNA prevalence was during March–April, with a minor peak during September–October, and a dip during July–August. In southwestern China, the peak was during September–October and the dip during March–April. The majority of subtype 4a cases (63/82, 76·83%) were detected in the first half of the year, while the majority of subtype 4b cases (26/29, 89·66%) were concentrated in the second half of the year, suggesting that different subtypes contribute to different peaks. Our results indicate that the distribution of HEV subtypes is associated with seasonal patterns.


1972 ◽  
Vol 4 (1) ◽  
pp. 107-116 ◽  
Author(s):  
John Stoeckel ◽  
A. K. M. Alauddin Choudhury

SummaryAn analysis of the monthly distribution of births in two areas of Matlab Thana, East Pakistan, indicates that there is a seasonal variation in births different from what would be expected by chance. The highest proportion of births occur in the last three months of a year and the lowest proportion between May and July. Investigation into some of the environmental and social factors which might contribute to the seasonal pattern revealed the following: mean minimum monthly temperature 9 months before birth was inversely related to the number of births; all occupations had seasonal patterns different from what would be expected by chance and the business and mill-and-office occupations had distributions significantly different from each other; the distribution of births for all pregnancy orders was different from chance and the distribution for first order pregnancies was significantly different from those for third and fourth or higher orders.


Author(s):  
Daniel Deitch ◽  
Alon Rubin ◽  
Yaniv Ziv

AbstractNeuronal representations in the hippocampus and related structures gradually change over time despite no changes in the environment or behavior. The extent to which such ‘representational drift’ occurs in sensory cortical areas and whether the hierarchy of information flow across areas affects neural-code stability have remained elusive. Here, we address these questions by analyzing large-scale optical and electrophysiological recordings from six visual cortical areas in behaving mice that were repeatedly presented with the same natural movies. We found representational drift over timescales spanning minutes to days across multiple visual areas. The drift was driven mostly by changes in individual cells’ activity rates, while their tuning changed to a lesser extent. Despite these changes, the structure of relationships between the population activity patterns remained stable and stereotypic, allowing robust maintenance of information over time. Such population-level organization may underlie stable visual perception in the face of continuous changes in neuronal responses.


1982 ◽  
Vol 2 (1-2) ◽  
pp. 197-212 ◽  
Author(s):  
Michael D. Koontz ◽  
John P. Robinson

Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 522 ◽  
Author(s):  
Qiang Liu ◽  
Fengri Li

Understanding the spatial and seasonal variations in leaf physiology is critical for accurately modeling the carbon uptake, physiological processes and growth of entire canopies and stands. For a 17-year-old Larix olgensis Henry plantation, vertical whorl-by-whorl sampling and analyses of seasonally repeated measurements of major photosynthetic parameters were conducted, and the correlations between photosynthetic parameters and environmental conditions, leaf morphological traits and spatial position within the crown were analyzed. According to the correlations, the photosynthetic parameters were standardized based on the environmental conditions to avoid the influence of the changing environment on the patterns of spatial and seasonal variations of photosynthetic parameters. The results showed that the standardized light-saturated net photosynthetic rate (SPmax), standardized dark respiration (SRd) and standardized stomatal conductance under saturated light (Sgs-sat) were all negatively related to the relative depth into the crown (RDINC) throughout the growing season. However, their vertical patterns were different during the development of the phenological phase. In addition, different gradients of environmental conditions also influenced the values and the range of the vertical variation in photosynthesis. High temperature and low humidity usually resulted in smaller values and weaker vertical variations of SPmax and Sgs-sat, but larger values and more obvious vertical variations in SRd. SPmax and Sgs-sat usually exhibited a parabolic seasonal pattern in different vertical positions within the crown; however, SRd generally followed a concave pattern. These seasonal patterns were all weaker with increasing RDINC. Different environments also exhibited a significant influence on the seasonal patterns of photosynthesis. We suggested that standardization is necessary before analyzing spatial and seasonal variations. A single environmental condition could not represent the spatial and seasonal patterns under all gradients of the environment. Spatial and seasonal variations should be simultaneously analyzed because they are related to each other.


2007 ◽  
Vol 67 (2) ◽  
pp. 197-202 ◽  
Author(s):  
C. Passadore ◽  
L. Giménez ◽  
A. Acuña

We studied the temporal patterns of macroinfaunal distribution in the estuarine portion of Pando Stream, Uruguay. We found a very low number of species and a high dominance of the polychaete Heteromastus similis. There were clear seasonal patterns in abundance with almost all species peaking in autumn, coinciding with the periods of higher salinity. Minimal values were found in winter and spring when salinity was at a minimum. We suggest that the seasonal pattern is a consequence of the combined effects of recruitment, and of high osmotic stress and disturbance during the periods of freshwater discharge that are common in winter and spring.


2007 ◽  
Vol 97 (6) ◽  
pp. 3859-3867 ◽  
Author(s):  
Hiroshi Okamoto ◽  
Yoshikazu Isomura ◽  
Masahiko Takada ◽  
Tomoki Fukai

Temporal integration of externally or internally driven information is required for a variety of cognitive processes. This computation is generally linked with graded rate changes in cortical neurons, which typically appear during a delay period of cognitive task in the prefrontal and other cortical areas. Here, we present a neural network model to produce graded (climbing or descending) neuronal activity. Model neurons are interconnected randomly by AMPA-receptor–mediated fast excitatory synapses and are subject to noisy background excitatory and inhibitory synaptic inputs. In each neuron, a prolonged afterdepolarizing potential follows every spike generation. Then, driven by an external input, the individual neurons display bimodal rate changes between a baseline state and an elevated firing state, with the latter being sustained by regenerated afterdepolarizing potentials. When the variance of background input and the uniform weight of recurrent synapses are adequately tuned, we show that stochastic noise and reverberating synaptic input organize these bimodal changes into a sequence that exhibits graded population activity with a nearly constant slope. To test the validity of the proposed mechanism, we analyzed the graded activity of anterior cingulate cortex neurons in monkeys performing delayed conditional Go/No-go discrimination tasks. The delay-period activities of cingulate neurons exhibited bimodal activity patterns and trial-to-trial variability that are similar to those predicted by the proposed model.


The Auk ◽  
2004 ◽  
Vol 121 (1) ◽  
pp. 110-117 ◽  
Author(s):  
Valentin Amrhein ◽  
Hansjoerg P. Kunc ◽  
Marc Naguib

Abstract Seasonal patterns of singing activity of male birds have been thoroughly studied, but little is known about how those patterns vary with time of day. Here, we censused mated and unmated male Nightingales (Luscinia megarhynchos) at four different hours of the day throughout the breeding cycle. In unmated males, singing activity increased until the young hatched in their neighborhood, and the seasonal variation was similar at each of the four hours of the day. In mated males, however, the seasonal patterns of singing activity differed between hours of the day. In morning (about the hour of egg-laying) and during the dusk chorus, the singing activity of mated males was strongly influenced by the females' reproductive state: singing activity was low before egg-laying and during incubation, but high during the egg-laying period. In the dawn chorus, however, singing activity showed a similar seasonal pattern in mated and unmated males and was high until late stages of the breeding cycle. Our results suggest that the social context influences singing behavior to a varying degree across the season, and that this variation also depends on time of day. The hour of data collection thus is an important but often neglected factor when seasonal changes of singing activity are studied.


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