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At least 19 recordsLinked to original sources
PubMed1978

Seasonal variation in admissions of psychiatric patients and its relation to seasonal variation in their births.

Inpatient admissions to all psychiatric hospital beds in England and Wales in 1970-73 were studied by month of admission for eight diagnostic groups. The admission rates for schizophrenia showed a pronounced seasonal variation, with a maximum in summer. The seasonal pattern for schizophrenia was very similar to the one shown for mania, although somewhat less marked. The admission rates for neurosis and for the large group of 'all other non-psychotic mental illness' showed little evidence of seasonal variation as there was could largely be explained by social factors. In schizophrenic and manic patients, the pattern of seasonal admissions (peak months July and August) is similar to the pattern reported for their births (peak months February and March). This is consistent with the hypothesis of an abnormal seasonal pattern of parental conception as the cause of the abnormal birth pattern.

Bipolar Disorder↗
PubMed1979

Seasonal migration and seasonal variation in fecundability: effects on birth rates and birth intervals.

Seasonal patterns in conception rates have been documented in several recent studies. In this paper, a mathematical model of the reproductive process is developed through which the impact of such variation in conception rates is assessed. It is found that the effect on fertility can be quite substantial, but that the birth rate when seasonal variation is occurring is approximated well by the birth rate calculated when conception rates are constant at their mean. These results indicate that further documentation of seasonality in conception rates and exploration of the causes of these patterns and their change is an important area for demographic research.

Birth Rate↗
PubMed2026

Rumen DNA virome plasticity and viral metabolic potential are associated with seasonal adaptation in grazing yak and cattle on the Qinghai-Tibet Plateau.

BACKGROUND: As a diverse and abundant component of the rumen ecosystem, viruses interact with other microorganisms and are thought to influence microbial metabolism and host productivity. However, how the rumen virome responds to seasonal fluctuations in extreme environments remains poorly understood. Here, metagenomic analyses were used to investigate temporal dynamics of viral diversity, functional potential, and virus-host associations in the rumen virome of yak and cattle on the Qinghai-Tibet Plateau across warm and cold seasons. RESULTS: Rumen viral communities exhibited pronounced seasonal variation in both yaks and cattle, with higher alpha diversity observed during the cold season than in the warm season. Across seasons, the yak rumen virome showed greater alpha diversity and community stability than that of cattle. In total, 27,353 temperate and 31,976 virulent viral operational taxonomic units (vOTUs) were identified, predominantly belonging to the class Caudoviricetes. These viruses were linked to microbial hosts spanning 24 bacterial and 8 archaeal phyla, with Bacteroidota and Bacillota representing the dominant lineages. Virus-host associations were more numerous in the cold season and showed distinct host-specific patterns between yaks and cattle. Cold-season virome exhibited reduced diversity of anti-defense genes and enrichment of auxiliary metabolic genes (AMGs) associated with fatty acid metabolism and hemicellulose degradation. Notably, greater divergence between yaks and cattle was observed during the cold season: the yak rumen virome was enriched in pathways related to amino acid, lipid, and energy metabolism, as well as cellulose-degrading CAZyme families, whereas the cattle rumen virome showed enrichment in general carbohydrate metabolism and replication and repair processes. CONCLUSION: Seasonal plasticity of rumen DNA virome and pronounced interspecific divergence between yaks and cattle provide insight into their distinct microbial processes in the harsh environment of the Qinghai-Tibet Plateau. These findings suggest that the rumen DNA virome exhibits complex ecological and functional responses to seasonal variation and may be associated with host-microbiome interactions and nutrient utilization under environmental stress. This study highlights the ecological relevance of rumen viral genomes in understanding virus-microbiome interactions, microbial adaptation, and nutrient utilization in high-altitude ruminants.

Auxiliary metabolic genes↗
PubMed1977

Behavioural and hormonal responses of male rhesus monkeys introduced to females in the breeding and non-breeding seasons.

Six adult male rhesus monkeys were introduced individually to an all-female group for 10 days during the mating season. The initial aggressive responses of the females were rapidly replaced by positive social behaviour, and each male achieved alpha status and had access to social and sexual partners. A repetition of this paradigm in the non-breeding season produced significantly more female aggression, and no male attained high rank or engaged in sexual or other social behaviour. Male testosterone levels rose following introduction to the females in both seasons, but were significantly higher during the breeding season. Hormonal levels following removal from the females suggest a complex interplay between social, sexual and seasonal variables and recent social experiences. The differences in female social behaviour with newly introduced males, as a function of season, suggest an explanation for the seasonal limitation of male troop transfers.

Aggression↗
PubMed1975

Histochemical studies on the mucosubstances in the ovotestis of a hermaphrodite land pulmonate Semperula maculata in seasonal breeding-aestivation cycle.

With a view to augment the cytochemical localization characterization and, probable functional significance of mucosubstances in the ovotestis in the reproductive physiology of land pulmonates, the mucosubstances were investigated in the ovotestis of a land snail, Semperula maculata (Stylommatophora) in the seasonal breeding-aestivation cycle. Widely accepted, recent and well-established histochemical techniques were emoloyed. The results showed that the cells in the germinal epithelium of the follicular wall, were endowed with a capacity of synthesis of neutral muco-substances. They also contained glycogen. The nurse cells contained neutral mucosubstances and glycogen in them, while maturing ovum contained hyaluronic acid and protein. Among all the male germ cell stages, only matured sperms showed sialoglycoprotein in their heads and glycogen in the tails. The seasonal variations in the mucosubstances showed that the synthesis of the mucosubstances in the male germ cells of the ovotestis was initiated at the end of the breeding season and attained a maximum in the post-breeding season. Most strikingly the presence of the sperm in the follicular cavity was a permanent feature throughout the seasonal breeding-aestivation cycle of the snails. The synthesis of the mucosubstances in the ovum and the nurse cells was initiated somewhat earlier in the post-breeding season and attained a peak prior to the active breeding season. The importance of the mucosubstances synthesised by the different cells of the ovotestis, is discussed with reference to the reproductive physiology of the snails.

Animals↗
PubMed2026

Multi-omics unveils seasonal remodeling and metabolic crosstalk between testis and abdominal fat body in a non-amplexus stream frog Nanorana taihangnica (Anura: Dicroglossidae).

BACKGROUND: Energy allocation between reproduction and survival represents a fundamental life-history challenge for animals in seasonal environments. Using integrated transcriptomics and metabolomics, we investigated Nanorana taihangnica (Anura: Dicroglossidae), a non-amplexus stream frog endemic to China, to elucidate the seasonal morphological and molecular coordination between the testis and abdominal fat body. RESULTS: Morphological analysis showed that fat body adipocyte cross-sectional area minimized at the end of the breeding season but rapidly recovered thereafter, while testicular volume continued declining post-breeding and only recovered during the non-breeding period. During breeding season, multi-omics analyses revealed that the fat body enhanced fatty acid oxidation, upregulated histidine-carnosine metabolism, activated NAD+ metabolism and FOXO3-mediated antioxidative responses to mitigate metabolic stress, and regulated adipocyte survival and apoptosis via sphingolipid signaling. Seasonal testicular development was centrally regulated by the mTOR signaling pathway, whose activity integrated autophagy levels, NAD+ availability, and aspartate metabolism to coordinate spermatogonial proliferation and spermatogenesis. CONCLUSIONS: This study demonstrates that N. taihangnica optimizes seasonal energy storage, allocation, and reproductive investment through molecular and metabolic crosstalk between the fat body and testis, providing empirical insights into the physiological integration of life-history strategies in animals inhabiting fluctuating environments.

Animals↗
PubMed1979

Seasonality in biochemical determinations: a source of variance and a clue to the temporal incidence of affective illness.

Systematic investigation of seasonal variations revealed unimodal annual rhythms in platelet serotonin uptake and DBH activity, bimodal seasonal rhythms in free and total tryptophan, melatonin, and platelet serotonin, and significant fluctuations of higher frequency in platelet MAO activity and protein. The methodological importance of seasonality is emphasized by the fact that the seasonal changes noted were often greater than differences previously found in the same parameters between depressive patients and controls. Since seasonal rhythms are circadian in origin, impairment of a central 24-hour biological clock could provide a common basis for circadian rhythm disturbances and seasonality in affective disorders.

Adult↗
PubMed1975

Studies on the mucosubstances elaborated by female duct of a land pulmonate Semperula maculata in seasonal breeding-aestivation cycle.

With a view to augmenting the understanding of the mucosubstances elaborated by the epithelial gland cells in the female duct of stylommatophoran pulmonate snail in general and finding out the seasonal variations in them during the breeding seasonal cycle of the snails in particular, the female duct mucosubstances were investigated in detail employing recent well-established histochemical techniques. The results showed that the gland cells in the female duct elaborated mucosubstances consisting of neutral mucins, glycogen, weakly sulfated sulfomucins, strongly sulfated sulfomucins and sialomucins. The study of cellular sites of mucosubstance elaboration showed that there are five different types of cells, the first type elaborated neutral mucins, the second weakly sulfated sulfomucins, the third strongly sulfated sulfomucins, the fourth sialomucins and the fifth glycogen. The seasonal variations in the mucosubstances showed that the acidic mucosubstance elaboration begins just before the post-breeding period and reaches a maximum in the pre-breeding season. Cyclic variations not only in the amount of the different mucosubstances but also in the number of cells elaborating them were witnessed in seasonal breeding-aestivation cycle. Since the results appear to indicate that the stages in the maturation of female sex cells in the ovotestis and uterus are closely related to the secretory process of the glandular cells in the female duct in the seasonal reproductive cycle of these snails, the importance of the mucosubstances secreted by the gland cells in the female duct is discussed with reference to the reproductive physiology of the snails.

Animals↗
PubMed1979

Fitness assessment of English league soccer players through the competitive season.

A battery of 26 tests was administered to professional soccer players (n = 31) at 3 points during the competitive season. Significant changes from start to mid-season were limited to improved muscular power, increased resting heart rate (fH), decreased force expiratory flow (FEF) and ankle mobility. No further changes with the duration of the competitive season were observed. Differences between squads were predominantly cardiac function measures at mid-season, and strength, muscular power and limb girths at the end of the season. The First Team squad had consistently less fat and poorer ankle mobility. It seems that mean fitness levels remain relatively stable during the playing season, though the measures significantly discriminating between the top and reserve squads fluctuate.

Adolescent↗
PubMed2024

Seasonal hydrological dynamics affected the diversity and assembly process of the antibiotic resistome in a canal network.

The significant threat of antibiotic resistance genes (ARGs) to aquatic environments health has been widely acknowledged. To date, several studies have focused on the distribution and diversity of ARGs in a single river while their profiles in complex river networks are largely known. Here, the spatiotemporal dynamics of ARG profiles in a canal network were examined using high-throughput quantitative PCR, and the underlying assembly processes and its main environmental influencing factors were elucidated using multiple statistical analyses. The results demonstrated significant seasonal dynamics with greater richness and relative abundance of ARGs observed during the dry season compared to the wet season. ARG profiles exhibited a pronounced distance-decay pattern in the dry season, whereas no such pattern was evident in the wet season. Null model analysis indicated that deterministic processes, in contrast to stochastic processes, had a significant impact on shaping the ARG profiles. Furthermore, it was found that Firmicutes and pH emerged as the foremost factors influencing these profiles. This study enhanced our comprehension of the variations in ARG profiles within canal networks, which may contribute to the design of efficient management approaches aimed at restraining the propagation of ARGs.

Seasons↗
PubMed2025

Tracking microplastic contamination across seasons in a freshwater reservoir: Evidence from surface water, sediments, and fishes.

Microplastics (MPs) are prevalent contaminants in aquatic environments, posing substantial ecological and health risks. These particles migrate within the different layers of aquatic bodies with time and affect the respective biota. Thus, to get an in-depth understanding of the particles, this current study investigated the seasonal distribution, morphological and chemical characteristics, along with potential ecological and human health impacts in the samples including surface water, sediment, and fish from a drinking water supplying reservoir in eastern India. Across three different seasons, pre-monsoon, monsoon, and post-monsoon samples were collected using optimized methods. Results revealed distinct seasonal trends: MP abundance in surface water peaked during the monsoon (mean: 1.15 MPs/L), while sediment showed the highest concentrations in the pre-monsoon (mean: 596 MPs/kg), indicating temporal accumulation dynamics influenced by runoff, hydrodynamics, and sedimentation. Fish gut analysis confirmed ingestion of MPs across five species, with concentrations ranging from 26 to 100 MPs/kg, depending on feeding habits. The most dominant MP type were fragments, followed by fibers, films, and beads. Polymer analysis via µFTIR identified polyethylene, polypropylene, and polyvinyl chloride as prevalent, with hazard assessments (i.e., Polymer Hazard Index (PHI)) indicating medium to very high ecological risks. Heavy metal association was more dominant in the MPs isolated from sediments than the waterborne MPs. Pollution Load Index (PLI) values were > 1 in most seasons, confirming contamination. Health risk analysis suggested potential exposure through both drinking water and fish consumption. This study emphasizes the need for seasonal monitoring, improved waste management, and mitigation strategies to address MP pollution in freshwater ecosystems.

Microplastics↗
PubMed2026

Seasonal variation in the office and ambulatory blood pressure control in patients treated with two dual antihypertensive therapies.

We investigated seasonal variation in the office and ambulatory blood pressure control in hypertensive patients treated with two single-pill dual-combination antihypertensive therapies. The study participants (n&#x2009;=&#x2009;560) were hypertensive patients enrolled in a 24-week therapeutic study. Antihypertensive treatment was initiated with amlodipine/benazepril 5/10&#x2009;mg/day or benazepril/hydrochlorothiazide 10/12.5&#x2009;mg/day, with the possible up-titration to 10/20&#x2009;mg/day or 20/25&#x2009;mg/day during follow-up, respectively. Office blood pressure was measured at each clinic visit, and ambulatory blood pressure monitoring was performed at baseline and 24-week follow-up. At 24 weeks of follow-up, in patients who continued antihypertensive treatment (n&#x2009;=&#x2009;511), the proportion of up-titration to higher dosages was significantly different across seasons of treatment commencement in the benazepril/hydrochlorothiazide group (P&#x2009;=&#x2009;0.002), but not in the amlodipine/benazepril group (P&#x2009;=&#x2009;0.84). The between-group difference was significantly different in 134 patients who commenced treatment in winter (18.9% vs. 5.0%, P&#x2009;=&#x2009;0.02), but not in 377 patients who commenced treatment in the other seasons (P&#x2009;&#x2265;&#x2009;0.33). The control rate of office blood pressure (<140/90&#x2009;mmHg) was significantly different across seasons of treatment commencement in the amlodipine/benazepril group (P&#x2009;=&#x2009;0.01), but not in the benazepril/hydrochlorothiazide group (P&#x2009;=&#x2009;0.16). The mean changes from baseline to 24-week follow-up tended to be smaller in the benazepril/hydrochlorothiazide than amlodipine/benazepril group in 24-h (mean between-group difference, -2.8&#x2009;mmHg) and daytime diastolic blood pressure (mean between-group difference, -3.2&#x2009;mmHg) in patients who commenced treatment in winter, though statistical significance was not achieved (P&#x2009;&#x2265;&#x2009;0.07). In conclusion, there was seasonality in the clinic and ambulatory blood pressure-lowering effect of antihypertensive drug combinations, with a marginally significant difference in treatment intensity and blood pressure control between treatment with amlodipine or hydrochlorothiazide in combination with benazepril.

Ambulatory blood pressure↗
PubMed1975

Seasonal variations in the composition of urine in relation to calcium stone-formation.

1. A retrospective cross-sectional study was carried out on data derived from single 24 h urine collections from 246 male idiopathic calcium stone-formers. 2. The daily urine volume and pH and the exretions of calcium, oxalate, phosphate, creatinine and magnesium were related to the time of year when the urine was collected, and the saturation of urine with calcium oxalate and octocalcium phosphate calculated for each month. 3. There were significant seasonal variations in the urinary excretion of calcium and oxalate, each showing a maximum during the summer months and a minimum in the winter. There was no significant seasonal variation in urinary pH, volume, creatinine, phosphate or magnesium. 4. There was a significant increase in the saturation of urine with calcium oxalate and a trend towards higher saturation levels of octo-calcium phosphate in the summer. These changes were dependent only on the seasonal variation in urinary calcium and oxalate and not on urine volume. 5. A retrospective study of the seasonal incidence of stone episodes among these 246 stone-formers showed that the rate of stone passage per month was 50% higher in the summer than in the winter. There was no significant seasonal variation in the incidence of stones removed surgically.

Calcium↗
PubMed1977

Seasonal changes of plasma estradiol and progesterone in the Japanese monkey (Macaca fuscata fuscata).

The plasma levels of estradiol and progesterone in 5 mature female Japanese monkeys (Macaca fuscata fuscata) throughout a breeding and nonbreeding season were measured by radioimmunoassay. As the breeding season approached, plasma estradiol levels started to increase and a few elevations were detected. However, neither a plasma progesterone rise nor menstrual bleeding was seen. Menstrual bleeding began in December and recurred regularly 4 or 5 times at 4 week intervals until April. During this period, cyclic estradiol elevations (150-250 pg/ml) and luteal progesterone rises (2.0-5.3 ng/ml) were observed. After the last menstruation in March or April, two animals showed an estradiol elevation, but progesterone levels remained in the basal range and amenorrhea persisted. These data indicated that female Japanese monkeys ovulate 4 or 5 times a year, i.e., their breeding season is definitely defined. The changes of both steroids in transitional periods between nonbreeding and breeding, and breeding and nonbreeding seasons, suggested that some follicle development occurred in these periods. The elucidation of the mechanisms involved in the seasonal variation of reproductive functions in the Japanese monkey may provide useful information concerning some aspects of amenorrhea in human females.

Animals↗
PubMed1978

Seasonal change of membrane potential across the proximal tubular epithelium in bullfrog kidneys.

In order to examine the seasonal changes in the relationship between the membrane potential and potassium activity of proximal tubular epithelium, a micropuncture study was performed with potassium selective microelectrodes on the kidney of the bullfrog (Rana catesbeiana) in two different seasons: winter (7 degrees C) and summer (20 degrees C). The potasssium activity in winter animals (7 degrees C) was 2.92 +/- 0.33 (mean +/- S.D., n = 20), 63.2 +/- 12.7 (n = 26), and 2.68 +/- 0.19 (n = 26) mM for the tubular fluid, cell, and plasma, whereas that in summer animals (20 degrees C) was 2.84 +/- 0.05 (n = 22), 61.8 +/- 11.2 (n = 24), 2.63 +/- 0.24 (n = 24) mM, respectively, indicating no seasonal difference. On the other hand, the mean values of the membrane PD in winter animals were 59.4 +/- 1.8 (n = 26) and 71.7 "/- 7.2 (n = 26) mV for the luminal and peritubular borders, whereas those in summer animals were 55.1 +/- 1.7 (n = 24) and 63.9 +/- 6.9 (n = 24) mV, respectivley, indicating that there was a significant seasonal difference (p less than 0.05 and p less than 0.001). Hence, compared to winter animals, the changes in the electrochemical profile for potassium in summer animals were: 1) the peritubular membrane PD is lower and 2) the transtubular electrochemical gradient is less steep. The sodium permeability calculated as the best fitting for a modified Goldman equation was 0.01 and 0.03 for winter and summer animals, respectively. In view of the fact the potassium in the cell and luminal fluid of the proximal tubule is kept at similar levels, potassium homeostasis is maintained in both groups of animals. The seasonal changes in electrical potentials are probably be due to an increase of cellular membrane permeability to ions other than potassium and to increased paracellular shunt conductance through the epithelium.

Animals↗
PubMed1979

Seasonal changes in malnutrition and diarrheal disease among preschool children in El Salvador.

The nutritional status of preschool children in a rural El Salvadoran population was assessed quarterly for 1 year using height, weight and arm circumference measurements in order to define seasonal changes in malnutrition. Seasonal patterns in the incidence of reported malnutrition and diarrheal disease from the local clinic serving the study population and on the national level for EL Salvador were also assessed and were compared with field measurements. Results indicated a similar seasonal increase in both measured malnutrition and in the reported incidence of malnutrition and diarrheal disease occurring at the onset of the rainy season. The results confirm the existence and indicate the magnitude of seasonal changes in malnutrition and diarrheal disease in a preschool population.

Body Height↗