scholarly journals Nest Turrets of Acromyrmex Grass-Cutting Ants: Micromorphology Reveals Building Techniques and Construction Dynamics

Insects ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 140 ◽  
Author(s):  
Marcela I. Cosarinsky ◽  
Daniela Römer ◽  
Flavio Roces
Keyword(s):  
Nest Entrance ◽  
Thin Sections ◽  
Age Dependent ◽  
Over Time

Acromyrmex fracticornis grass-cutting ants construct conspicuous chimney-shaped nest turrets made of intermeshed grass fragments. We asked whether turrets are constructed by merely piling up nearby materials around the entrance, or whether ants incorporate different materials as the turret develops. By removing the original nest turrets and following their rebuilding process over three consecutive days, age-dependent changes in wall morphology and inner lining fabrics were characterized. Micromorphological descriptions based on thin sections of turret walls revealed the building behaviors involved. Ants started by collecting nearby twigs and dry grass fragments that are piled up around the nest entrance. Several large fragments held the structure like beams. As a net-like structure grew, soil pellets were placed in between the intermeshed plant fragments from the turret base to the top, reinforcing the structure. Concomitantly, the turret inner wall was lined with soil pellets, starting from the base. Therefore, the consolidation of the turret occurred both over time and from its base upwards. It is argued that nest turrets do not simply arise by the arbitrary deposition of nearby materials, and that workers selectively incorporate large materials at the beginning, and respond to the developing structure by reinforcing the intermeshed plant fragments over time.

CHARACTERISTICS OF AGE-DEPENDENT CHANGES IN THE URINE'S PROTEOM COMPOSITION OF THE HEALTHY PERSONS (EXPERIMENTAL AND THEORETICAL STUDY)

2020 ◽  
pp. 735-740
Author(s):  
Л. Х. Пастушкова ◽  
Д. Н. Каширина ◽  
А. Г. Гончарова ◽  
Н. Б. Захарова ◽  
Е. С. Тийс ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Insulin Signaling ◽  
Defense Mechanisms ◽  
Theoretical Study ◽  
Clinical Manifestations ◽  
Age Dependent ◽  
First Time ◽  
Healthy Persons ◽  
Over Time

Впервые описаны белки, достоверно увеличивающиеся и уменьшающиеся в моче с возрастом в интервале 20-60 лет. Охарактеризованы комбинации белков, связанных с изменением иммунных процессов, нарушением реологии крови, в том числе риском коагулопатии, противоопухолевых защитных механизмов, инсулинового сигнального пути, с изменением характеристик клеточного деления и качества новообразованной ткани. Таким образом, возрастная динамика основных процессов запускает каскад реакций, проявляющихся в замыкании «патологических биохимических кругов», которые формируют предпосылки к развитию заболеваний и, с течением времени, клинические проявления. For the first time proteins are described, reliably increasing and decreasing in urine with age in the range of 20 to 60 years. The combinations of proteins associated with changes in immune processes, violation of blood reology, including the risk of coagulopathy, anticancer defense mechanisms, insulin signaling pathway, changes in cell characteristics are characterized division and quality of the newly formed fabric. Thus, the age dynamics of the main processes triggers a cascade of reactions manifested in the closure of «pathological biochemical circles» that form the prerequisites for the development of diseases and, over time, clinical manifestations.

Trends in the Incidence of Legal Problems and in the Use of Lawyers

1978 ◽  
Vol 3 (2) ◽  
pp. 289-313 ◽  
Author(s):  
Yakov Avichai
Keyword(s):  
Mathematical Model ◽  
Age Groups ◽  
Strong Increase ◽  
Government Regulations ◽  
Legal Problems ◽  
Socioeconomic Changes ◽  
Age Dependent ◽  
Changes Over Time ◽  
Near Future ◽  
Over Time

Changes in the law, government regulations, socioeconomic changes, increased consumerism, the public's level of awareness—all these and other factors influence the population's demand over time for lawyers' services. This article analyzes the changes over time in the two elements that determine the demand for lawyers: the number of legal problems encountered by the population and the rate of use of lawyers in solving these problems. After showing that sequential occurrences of legal problems are not independent of each other and are age dependent, the author develops a mathematical model that explains the variability in the present number of problems encountered by different age groups. The number of problems is found to result from a relatively mild accumulation with age of legal problems, coupled with a strong increase in the number of problems from generation to generation. The analysis of individual legal problems reveals a variety of patterns from problem to problem in both the level of occurrence and the rate of use of lawyers for such problems. The author concludes that the combined effect of occurrence and utilization will operate toward a continuing increase in the demand for lawyers'services at least for the very near future.

scholarly journals Selection and spatial arrangement of building materials during the construction of nest turrets by grass-cutting ants

2020 ◽  
Vol 7 (10) ◽  
pp. 201312
Author(s):  
Daniela Römer ◽  
Marcela I. Cosarinsky ◽  
Flavio Roces
Keyword(s):  
Building Materials ◽  
Material Selection ◽  
Spatial Location ◽  
Spatial Arrangement ◽  
The Self ◽  
Nest Entrance ◽  
Self Organized ◽  
The Impact ◽  
Over Time ◽  
Selection Of

Ants build complex nest structures by reacting to simple, local stimuli. While underground nests result from the space generated by digging, some leaf- and grass-cutting ants also construct conspicuous aboveground turrets around nest openings. We investigated whether the selection of specific building materials occurs during turret construction in Acromyrmex fracticornis grass-cutting ants, and asked whether single building decisions at the beginning can modify the final turret architecture. To quantify workers' material selection, the original nest turret was removed and a choice between two artificial building materials, thin and thick sticks, was offered for rebuilding. Workers preferred thick sticks at the very beginning of turret construction, showed varying preferences thereafter, and changed to prefer thin sticks for the upper, final part of the turret, indicating that they selected different building materials over time to create a stable structure. The impact of a single building choice on turret architecture was evaluated by placing artificial beams that divided a colony's nest entrance at the beginning of turret rebuilding. Splitting the nest entrance led to the self-organized construction of turrets with branched galleries ending in multiple openings, showing that the spatial location of a single building material can strongly influence turret morphology.

scholarly journals DAF-16 and SMK-1 Contribute to Innate Immunity During Adulthood in Caenorhabditis elegans

2020 ◽  
Vol 10 (5) ◽  
pp. 1521-1539 ◽  
Author(s):  
Daniel R. McHugh ◽  
Elena Koumis ◽  
Paul Jacob ◽  
Jennifer Goldfarb ◽  
Michelle Schlaubitz-Garcia ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Immune System ◽  
Caenorhabditis Elegans ◽  
Host Defense ◽  
Insulin Signaling ◽  
Bacterial Pathogens ◽  
C Elegans ◽  
Link Type ◽  
Age Dependent ◽  
Over Time

Aging is accompanied by a progressive decline in immune function termed “immunosenescence”. Deficient surveillance coupled with the impaired function of immune cells compromises host defense in older animals. The dynamic activity of regulatory modules that control immunity appears to underlie age-dependent modifications to the immune system. In the roundworm Caenorhabditis elegans levels of PMK-1 p38 MAP kinase diminish over time, reducing the expression of immune effectors that clear bacterial pathogens. Along with the PMK-1 pathway, innate immunity in C. elegans is regulated by the insulin signaling pathway. Here we asked whether DAF-16, a Forkhead box (FOXO) transcription factor whose activity is inhibited by insulin signaling, plays a role in host defense later in life. While in younger C. elegansDAF-16 is inactive unless stimulated by environmental insults, we found that even in the absence of acute stress the transcriptional activity of DAF-16 increases in an age-dependent manner. Beginning in the reproductive phase of adulthood, DAF-16 upregulates a subset of its transcriptional targets, including genes required to kill ingested microbes. Accordingly, DAF-16 has little to no role in larval immunity, but functions specifically during adulthood to confer resistance to bacterial pathogens. We found that DAF-16-mediated immunity in adults requires SMK-1, a regulatory subunit of the PP4 protein phosphatase complex. Our data suggest that as the function of one branch of the innate immune system of C. elegans (PMK-1) declines over time, DAF-16-mediated immunity ramps up to become the predominant means of protecting adults from infection, thus reconfiguring immunity later in life.

Age-dependent metabolic effects of repeated hypoxemia in piglets

2000 ◽  
Vol 78 (4) ◽  
pp. 321-328 ◽  
Author(s):  
Aurore Côté ◽  
Jill Barter ◽  
Brian Meehan
Keyword(s):  
Lactic Acid ◽  
Body Temperature ◽  
Metabolic Rate ◽  
Cardiovascular Response ◽  
Alveolar Ventilation ◽  
Repeated Exposure ◽  
Metabolic Effects ◽  
Age Dependent ◽  
Lactate Levels ◽  
Over Time

The aim of this study was to determine whether repeated exposure to hypoxemia would modify the response to hypoxemia during maturation. We exposed piglets to three 1-h cycles of hypoxemia (PaO2 = 30 to 35 mmHg; 1 mmHg = 133.3 Pa) at 1 week (n = 9), 2-3 weeks (n = 10), and 4-5 weeks of age (n = 10). O2 consumption (VO2) and CO2 production (VCO2) were measured, and alveolar ventilation (VA) was derived from VCO2 and PaCO2. Levels of lactic acid (lactate) and serum catecholamines were also measured. With hypoxemia, time had a significant effect on VO2 and body temperature in an age-dependent fashion: that is, whereas the 1 week group and the 4-5 week group showed both variables decreasing over time, the 2-3 week group showed no drop in VO2 and a small increase in body temperature over time. Lactate levels increased with hypoxemia in all animals during the first exposure. However, with repeated exposures to hypoxemia, only the 2-3 week group continued to increase its lactate levels. Furthermore, the changes in lactate levels paralleled the changes in epinephrine levels with hypoxemia. We found, too, that although VA increased significantly with hypoxemia in all animals, this change was not modified by age or repeated exposures. No significant effects of age or repeated exposures were found in the cardiovascular response to hypoxemia. We concluded that, from a metabolic viewpoint, after repeated exposures to hypoxemia the 2-3 week animals responded differently.Key words: metabolic rate, lactic acid, maturation, catecholamines.

scholarly journals Predicting plasticity: acute context-dependent changes to vocal performance predict long-term age-dependent changes

2015 ◽  
Vol 114 (4) ◽  
pp. 2328-2339 ◽  
Author(s):  
Logan S. James ◽  
Jon T. Sakata
Keyword(s):  
Repeated Measures ◽  
Temporal Structure ◽  
Vocal Performance ◽  
Branch Points ◽  
Vocal Plasticity ◽  
Repeated Measures Design ◽  
Age Dependent ◽  
Context Dependent ◽  
The Stability ◽  
Over Time

Understanding the factors that predict and guide variation in behavioral change can lend insight into mechanisms of motor plasticity and individual differences in behavior. The performance of adult birdsong changes with age in a manner that is similar to rapid context-dependent changes to song. To reveal mechanisms of vocal plasticity, we analyzed the degree to which variation in the direction and magnitude of age-dependent changes to Bengalese finch song could be predicted by variation in context-dependent changes. Using a repeated-measures design, we found that variation in age-dependent changes to the timing, sequencing, and structure of vocal elements (“syllables”) was significantly predicted by variation in context-dependent changes. In particular, the degree to which the duration of intersyllable gaps, syllable sequencing at branch points, and fundamental frequency of syllables within spontaneous [undirected (UD)] songs changed over time was correlated with the degree to which these features changed from UD song to female-directed (FD) song in young-adult finches (FDyoung). As such, the structure of some temporal features of UD songs converged over time onto the structure of FDyoung songs. This convergence suggested that the FDyoung song could serve as a stable target for vocal motor plasticity. Consequently, we analyzed the stability of FD song and found that the temporal structure of FD song changed significantly over time in a manner similar to UD song. Because FD song is considered a state of heightened performance, these data suggest that age-dependent changes could reflect practice-related improvements in vocal motor performance.

scholarly journals Primary and Secondary Hypogonadism in Male Persons with Diabetes Mellitus

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
João Martin Martins ◽  
Mafalda de Pina Jorge ◽  
Catarina Martins Maia ◽  
João Roque ◽  
Carlos Lemos ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Statistical Analysis ◽  
Usual Care ◽  
Metabolic Control ◽  
Microvascular Disease ◽  
Total Testosterone ◽  
Age Dependent ◽  
Highly Correlated ◽  
Secondary Hypogonadism ◽  
Over Time

Aims. To characterize hypogonadism in male persons with diabetes mellitus. Patients and Methods. 184 consecutive male persons with diabetes were studied. Besides the usual care, total testosterone (TT), estradiol (E2), FSH, and LH were measured in the last appointment and in 40 patients, also in the next two appointments. Statistical analysis compared groups and explored factors for TT and LH levels. Results. TT levels were stable and highly correlated (r > 0.750, p < 0.001 ) over a 6–12-month period. 20% of the patients presented secondary hypogonadism (SH) and 18% presented primary hypogonadism (PH). SH was inversely related to HbA1 (partial r (rp) = 0.229, p < 0.005 ), while PH was directly related to age (r = 0.356, p < 0.001 ). TT levels were reduced independently by metformin (364 ± 160 vs. 431 ± 242 ng/dL, t = 2.241, p < 0.05 ) and statins (359 ± 156 vs. 424 ± 230 ng/dl, t = 2.224, p < 0.05 ). TT levels were inversely related to microvascular disease (rp = −0.169, p < 0.05 ). Discussion. TT levels were stable over time and hypogonadism was common. SH, generally clinically, is related to the diabetic state, while PH, generally subclinically, is an age-dependent process unrelated to diabetes. Low TT levels were related to older age, poor metabolic control, metformin and statins use, and microvascular disease.

Magnetic resonance imaging studies of age-dependent responses to scaled focal brain injury in the piglet

2003 ◽  
Vol 99 (3) ◽  
pp. 542-548 ◽  
Author(s):  
Ann-Christine Duhaime ◽  
Jill V. Hunter ◽  
Loretta L. Grate ◽  
Anje Kim ◽  
Jeffrey Golden ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Mechanical Trauma ◽  
Lesion Volume ◽  
Imaging Studies ◽  
Content Type ◽  
Age Dependent ◽  
The Brain ◽  
Over Time ◽  
Fine Print

Object. Whether the brain differs in its response to traumatic injury as a function of age remains unclear. To further investigate the age-dependent response of the brain to mechanical trauma, a cortical contusion model scaled for brain growth during maturation was used to study the evolution of injury over time as demonstrated on serial magnetic resonance (MR) imaging studies in piglets of different ages.Methods. Sixteen Yorkshire piglets received scaled cortical contusions. Animals were either 5 days (six animals), 1 month (five animals), or 4 months (five animals) of age at injury. These ages correspond developmentally to human infants, toddlers, and early adolescents, respectively. Serial MR imaging examinations, including fluid-attenuated inversion-recovery and T1-, T2-, and diffusion-weighted sequences were performed at 24 hours, 1 week, and 1 month after injury. Lesions were quantified and expressed as a ratio of the lesion volume divided by the volume of the uninjured hemisphere for each animal and each MR sequencing. Differences in relative lesion volume among the varied ages at a single time point and in lesion volume over time at each age were compared. In addition, the relationship between age and evolution of injury were analyzed using a two-compartment mathematical model. Histological features were examined at 1 month postinjury. Despite comparable injury inputs, the youngest animals had lesions whose volumes peaked earlier and resolved more quickly than those in older animals. The intermediate-age piglets (toddler) had the most pronounced swelling of any age group, and the oldest piglets (adolescent) had the latest peak in lesion volume.Conclusions. Scaled cortical contusions in piglets demonstrated age-dependent differences in injury response, both in magnitude and time course. These observations may shed light on development-related trauma response in the gyrencephalic brain.

scholarly journals Age-Dependent Enclosure Use in Juvenile Chinese Crocodile Lizards, Shinisaurus crocodilurus crocodilurus

2021 ◽  
Vol 2 (3) ◽  
pp. 406-415
Author(s):  
Kimberley C. Carter ◽  
James J. Hicks ◽  
Daniel Kane ◽  
Benjamin Tapley ◽  
Christopher J. Michaels
Keyword(s):  
Resource Use ◽  
Environmental Conditions ◽  
Sampling Period ◽  
Time Of Day ◽  
Water Bodies ◽  
Significant Difference ◽  
Age Dependent ◽  
Mixed Age ◽  
Time Resource ◽  
Over Time

This study compared the resource use of juvenile zoo-living Chinese crocodile lizards, Shinisaurus crocodilurus crocodilurus across three observation windows, spanning nine months, accounting for time of day and lizard age, and under consistent environmental conditions. Lizards showed a significant difference in proportionate resource use, quantified using a modified spread of participation indices between the second and final sampling period, such that with increasing age, resources were more equally utilised. The time of day did not have a significant effect on resource use. Lizards in this study significantly increased their use of water bodies and branches outside the bask zone and decreased their use of the land areas within the bask zones over time. Resource use data suggests the importance of providing enclosures which cater to ontogenetic shifts in captive individuals or within mixed age groupings.

Hyperplasia and accelerated hypertrophy of marrow adipocytes with knee immobilization were sustained despite remobilization

2020 ◽  
Vol 129 (4) ◽  
pp. 701-708
Author(s):  
Haodong Zhou ◽  
Guy Trudel ◽  
Konstantin Alexeev ◽  
Justin Thomas ◽  
Odette Laneuville
Keyword(s):  
Bone Marrow ◽  
Animal Model ◽  
Adipose Tissue ◽  
Weight Bearing ◽  
Bone Marrow Adipocytes ◽  
Multimodal Distributions ◽  
Age Dependent ◽  
Changes Over Time ◽  
Over Time ◽  
Rat Animal Model

This longitudinal study elucidates the response of marrow adipose tissue adipocytes in weight-bearing joints to changes in different mechanical environments, and we provide insight on the malleability of the changes over time. In a rat animal model, knee immobilization induced hyperplasia and accelerated the age-dependent hypertrophy of adipocytes. Changes in adipocyte number and size were sustained despite unassisted remobilization. Multimodal distributions of cell size were characteristic of bone marrow adipocytes.

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