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Sample records for age structure changing

  1. Changing family structure and aging issues.

    Science.gov (United States)

    Bae, H

    1987-12-01

    Rapid industrialization, adaptation of modern values, and rural-urban migration in Korea have led to the replacement of the extended family with the nuclear of conjugal family. In 1980, 13% of Korean households were 1-generational, 70% were 2-generational, 17% were 3-generational and less than 1% were 4-generational. This trend has had serious implications for the aged, who have become increasingly isolated from Korean society. Hindering the adaptation of the aged to modern society are their low educational level, rural concentration, low income, and high rate of female members. Adult children who are well educated and prosperous economically are most likely to refuse to take responsibility for aged parents. Since some 23% of the aged currently live alone, Korean society must assume some of the responsibility that has traditionally been accepted by family members. There is a need for systematic programming that takes into account the current sociodemographic circumstances of Korea's aged population. Incentives such as tax exemptions and aged care allowances should be considered to encourage children to take responsibility for their aged parents. To meet the needs of the growing number of aged who are disabled and without family support, the number of geriatric hospitals and institutions must be expanded. Also important are supplementary programs such as housekeeping services, meals on wheels, and day care. Although the expansion of social welfare programs and institutions for the aged is essential, they can not in themselves meet the emotional needs of the aged that have traditionally been served by family connectedness. PMID:12315151

  2. Age-related changes in brain structural covariance networks

    Directory of Open Access Journals (Sweden)

    Xinwei eLi

    2013-03-01

    Full Text Available Previous neuroimaging studies have suggested that cerebral changes over normal aging are not simply characterized by regional alterations, but rather by the reorganization of cortical connectivity patterns. The investigation of structural covariance networks (SCNs using voxel-based morphometry is an advanced approach to examining the pattern of covariance in gray matter volumes among different regions of the human cortex. To date, how the organization of critical SCNs change during normal aging remains largely unknown. In this study, we used an SCN mapping approach to investigate eight large-scale networks in 240 healthy participants aged 18–89 years. These participants were subdivided into young (18–23 years, middle aged (30–58 years, and older (61–89 years subjects. Eight seed regions were chosen from widely reported functional intrinsic connectivity networks. The voxels showing significant positive associations with these seed regions were used to describe the topological organization of an SCN. All of these networks exhibited non-linear patterns in their spatial extent that were associated with normal aging. These networks, except the primary motor network, had a distributed topology in young participants, a sharply localized topology in middle aged participants, and were relatively stable in older participants. The structural covariance derived using the primary motor cortex was limited to the ipsilateral motor regions in the young and older participants, but included contralateral homologous regions in the middle aged participants. In addition, there were significant between-group differences in the structural networks associated with language-related speech and semantics processing, executive control, and the default-mode network. Taken together, the results of this study demonstrate age-related changes in the topological organization of SCNs, and provide insights into normal aging of the human brain.

  3. Structural and Functional Changes With the Aging Kidney.

    Science.gov (United States)

    Denic, Aleksandar; Glassock, Richard J; Rule, Andrew D

    2016-01-01

    Senescence or normal physiologic aging portrays the expected age-related changes in the kidney as compared to a disease that occurs in some but not all individuals. The microanatomical structural changes of the kidney with older age include a decreased number of functional glomeruli from an increased prevalence of nephrosclerosis (arteriosclerosis, glomerulosclerosis, and tubular atrophy with interstitial fibrosis), and to some extent, compensatory hypertrophy of remaining nephrons. Among the macroanatomical structural changes, older age associates with smaller cortical volume, larger medullary volume until middle age, and larger and more numerous kidney cysts. Among carefully screened healthy kidney donors, glomerular filtration rate (GFR) declines at a rate of 6.3 mL/min/1.73 m(2) per decade. There is reason to be concerned that the elderly are being misdiagnosed with CKD. Besides this expected kidney function decline, the lowest risk of mortality is at a GFR of ≥75 mL/min/1.73 m(2) for age kidney functional reserve when they do actually develop CKD, and they are at higher risk for acute kidney injury.

  4. [Age changes of the connective tissue structures of human penis].

    Science.gov (United States)

    Klimachev, V V; Neĭmark, A I; Gerval'd, V Ia; Bobrov, I P; Avdalian, A M; Muzalevskaia, N I; Gerval'd, I V; Aliev, R T; Cherdantseva, T M

    2011-01-01

    This investigation was aimed at the study of age changes of penis connective tissue structures. Tissue fragments of penis were obtained from 20 cadavers of men at the age of 20-38 years in group I, and from 20 cadavers of men at the age of 41-59 years in group II. The criteria for the exclusion of material from the research were arterial hypertension, diabetes mellitus, atherosclerosis of internal iliac arteries, Peyronie's disease, and anomalies of genital organ development. It was shown that in the cavernous body of penis, aging was associated with the increased amount and thickening of collagen and argyrophilic fibers, decreased content and thinning of elastic fibers, and the reduced amount of smooth muscle cells (SMC). The average area of fibroblast and SMC nucleolus was not different in both groups studied. The average area of endotheliocyte nucleolus was equal to 1.9+/-0.9 microm2 in group II, being lower than that one in group I, in which this index was equal to 2.1+/-0.9 microm2. No differences in the content of type III and IV collagen were found between the study groups. Age-associated decrease in the average area of endothelial cell nucleolus in the cavernous bodies may reflect the reduction of the activity of these cells and may indicate the development of endothelial dysfunction, which is one of the most important steps in the morphogenesis of age-related male erectile dysfunction.

  5. Age-related changes of normal adult brain structure: analysed with diffusion tensor imaging

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yun-ting; ZHANG Chun-yan; ZHANG Jing; LI Wei

    2005-01-01

    Background It is known that the brain structure changes with normal aging. The objective of this study was to quantify the anisotropy and average diffusion coefficient (DCavg) of the brain in normal adults to demonstrate the microstructure changes of brain with aging.Methods One hundred and six normal adults were examined with diffusion tensor imaging (DTI). The fractional anisotropy (FA), 1-volume ratio (1-VR), relative anisotropy (RA) and average diffusion coefficient (DCavg) of different anatomic sites of brain were measured, correlated with age and compared among three broad age groups.Results Except in lentiform nucleus, the anisotropy increased and DCavg decreased with aging. Both anisotropy and DCavg of lentiform nucleus increased with aging. The normal reference values of DTI parameters of normal Chinese adult in major anatomic sites were acquired. Conclusions DTI data obtained noninvasively can reflect the microstructural changes with aging. The normal reference values acquired can serve as reference standards in differentiation of brain white matter diseases.

  6. A longitudinal study of structural brain network changes with normal aging

    Directory of Open Access Journals (Sweden)

    Kai eWu

    2013-04-01

    Full Text Available The aim of this study was to investigate age-related changes in the topological organization of structural brain networks by applying a longitudinal design over 6 years. Structural brain networks were derived from measurements of regional gray matter volume and were constructed in age-specific groups from baseline and follow-up scans. The structural brain networks showed economical small-world properties, providing high global and local efficiency for parallel information processing at low connection costs. In the analysis of the global network properties, the local and global efficiency of the baseline scan were significantly lower compared to the follow-up scan. Moreover, the annual rate of changes in local and global efficiency showed a positive and negative quadratic correlation with the baseline age, respectively; both curvilinear correlations peaked at approximately the age of 50. In the analysis of the regional nodal properties, significant negative correlations between the annual rate of changes in nodal strength and the baseline age were found in the brain regions primarily involved in the visual and motor/ control systems, whereas significant positive quadratic correlations were found in the brain regions predominately associated with the default-mode, attention, and memory systems. The results of the longitudinal study are consistent with the findings of our previous cross-sectional study: the structural brain networks develop into a fast distribution from young to middle age (approximately 50 years old and eventually became a fast localization in the old age. Our findings elucidate the network topology of structural brain networks and its longitudinal changes, thus enhancing the understanding of the underlying physiology of normal aging in the human brain.

  7. Changes of population by age and gender structure of Regions in the Republic of Macedonia

    Directory of Open Access Journals (Sweden)

    Resul Hamiti

    2015-07-01

    Full Text Available This paper analyzes the changes of population by age and the gender structure in the regions of the Republic of Macedonia. Age and gender is very important not only for the development of demographic process but also for the development of regions. They play an important role in planning the health care needs and other services with the socio-economic and cultural character. In this sense they affect the performance of demographic processes (births, deaths, marriages, etc. and are a result of bilateral relations fertility, mortality, migration movements and other social processes. The main objective of this paper is to identify the aging phenomenon of population in state level and regions. This paper also dedicates special importance to the changes of age and sex structure, during the period between1981-2014 in the regions of the republic of Macedonia.

  8. Structural, biochemical, cellular, and functional changes in skeletal muscle extracellular matrix with aging

    DEFF Research Database (Denmark)

    Kragstrup, Tue Wenzel; Kjaer, M; Mackey, A L

    2011-01-01

    The extracellular matrix (ECM) of skeletal muscle is critical for force transmission and for the passive elastic response of skeletal muscle. Structural, biochemical, cellular, and functional changes in skeletal muscle ECM contribute to the deterioration in muscle mechanical properties with aging...... in skeletal muscle ECM contribute to the increased stiffness and impairment in force generated by the contracting muscle fibers seen with aging. The cellular interactions provide and potentially coordinate an adaptation to mechanical loading and ensure successful regeneration after muscle injury. Some...

  9. Structural and functional changes of face and neck skin in women of different age groups

    OpenAIRE

    Makarchuk O.I.

    2008-01-01

    To define structural and functional changes of skin in women of different age groups and their relationships in this work intraoperational biopsy material of skin of 100 women at the age from 19 to 73 years, that was taken during standard surgery instrumentations for different defects of face and neck skin correction, was investigated. Skin material of cheek face region, temple region of head and anterior neck region was morphologically processed. To define parameters of microvessels and derm...

  10. Structural and functional changes of face and neck skin in women of different age groups

    Directory of Open Access Journals (Sweden)

    Makarchuk O.I.

    2008-01-01

    Full Text Available To define structural and functional changes of skin in women of different age groups and their relationships in this work intraoperational biopsy material of skin of 100 women at the age from 19 to 73 years, that was taken during standard surgery instrumentations for different defects of face and neck skin correction, was investigated. Skin material of cheek face region, temple region of head and anterior neck region was morphologically processed. To define parameters of microvessels and dermal fibroblasts, thickness of epidermis, serial sections was investigated with the help of morphometry. The range of skin hydratation was investigated with the help of Doppler and ultrasound techniques. It was determined, that involution dynamic of microvessel condition in papillary layer of derma coincides with grade reduction of relative volume of microvesseles bed, that was observed in greatest part in cheek region of face. There is growth of relative microvesseles volume in reticular layer of derma in women of older age groups. Microcirculation age changes include structural disorders of intrapapillary capillary loops, disorganization of arterioles in papillary and reticular layers of derma, disorders of venules because of the changes in microenvironmental fibrillar network. Essential structural and functional changes observed in skin of cheek region in women of 33-40 years and in temple region of head and anterior neck region in women of 41-50 years. It accompanied with thinning of epidermis and emergence of keratinocytes with defective tinctorial properties and also grade reduction in quantitative density of fibroblasts and limitation of their functional activity. There is essential correlation between quantitative parameters of microcirculation and marks of age dynamic of epidermis condition and range of skin hydratation.

  11. Aging population in change – a crucial challenge for structurally weak rural areas in Austria

    Directory of Open Access Journals (Sweden)

    Fischer Tatjana

    2014-03-01

    Full Text Available Besides population decline, structurally weak rural areas in Austria face a new challenge related to demographic change: the increasing heterogeneity of their aging population. From the example of the so-called ‘best agers’ - comprising people aged 55 to 65 years - this contribution makes visible patterns and consequences of growing individualized spatial behaviour and spatial perception. Furthermore, contradictions between claims, wishes and expectations and actual engagement and commitment to their residential rural municipalities are being pointed out. These empirically-based facts are rounded off by considerations on the best agers’ future migration-behaviour and the challenges for spatial planning at the municipal level.

  12. Ageing changes in the eye

    OpenAIRE

    Salvi, S M; Akhtar, S; Currie, Z

    2006-01-01

    Ageing changes occur in all the structures of the eye causing varied effects. This article attempts to review the parameters of what is considered within the “normal limits” of ageing so as to be able to distinguish those conditions from true disease processes. Improving understanding of the ageing changes will help understand some of the problems that the ageing population faces.

  13. Age-related changes of structures in cerebellar cortex of cat

    Indian Academy of Sciences (India)

    Changzheng Zhang; Tianmiao Hua; Zaiman Zhu; Xun Luo

    2006-03-01

    We studied the structures of the cerebellar cortex of young adult and old cats for age-related changes, which were statistically analysed. Nissl staining was used to visualize the cortical neurons. The immunohistochemical method was used to display glial fibrillary acidic protein (GFAP)-immunoreactive (IR) astrocytes and neurofilament-immunoreactive (NF-IR) neurons. Under the microscope, the thickness of the cerebellar cortex was measured; and the density of neurons in all the layers as well as that of GFAP-IR cells in the granular layer was analysed. Compared with young adult cats, the thickness of the molecular layer and total cerebellar cortex was significantly decreased in old cats, and that of the granular layer increased. The density of neurons in each layer was significantly lower in old cats than in young adult ones. Astrocytes in old cats were significantly denser than in young adult ones, and accompanied by evident hypertrophy of the cell bodies and enhanced immunoreaction of GFAP substance. Purkinje cells (PCs) in old cats showed much fewer NF-IR dendrites than those in young adults. The above findings indicate a loss of neurons and decrease in the number of dendrites of the PCs in the aged cerebellar cortex, which might underlie the functional decline of afferent efficacy and information integration in the senescent cerebellum. An age-dependent enhancement of activity of the astrocytes may exert a protective effect on neurons in the aged cerebellum.

  14. Changing Age and Household Patterns

    DEFF Research Database (Denmark)

    Højbjerg Jacobsen, Rasmus; Hougaard Jensen, Svend E.

    2014-01-01

    finances by almost 1% of GDP on the yearly budget. While the net fiscal effect of changing household structures is minor, the gross effects are substantial. In a future characterized by population ageing, public finances may be adversely affected by changes in both age and household structures, thus...

  15. Age-related structural and functional changes of low back muscles.

    Science.gov (United States)

    Hiepe, Patrick; Gussew, Alexander; Rzanny, Reinhard; Kurz, Eduard; Anders, Christoph; Walther, Mario; Scholle, Hans-Christoph; Reichenbach, Jürgen R

    2015-05-01

    During aging declining maximum force capacity with more or less unchanged fatigability is observed with the underlying mechanisms still not fully understood. Therefore, we compared morphology and function of skeletal muscles between different age groups. Changes in high-energy phosphate turnover (PCr, Pi and pH) and muscle functional MRI (mfMRI) parameters, including proton transverse relaxation time (T2), diffusion (D) and vascular volume fraction (f), were investigated in moderately exercised low back muscles of young and late-middle-aged healthy subjects with (31)P-MR spectroscopy, T2- and diffusion-weighted MRI at 3T. In addition, T1-weighted MRI data were acquired to determine muscle cross-sectional areas (CSA) and to assess fat infiltration into muscle tissue. Except for pH, both age groups showed similar load-induced MR changes and rates of perceived exertion (RPE), which indicates comparable behavior of muscle activation at moderate loads. Changes of mfMRI parameters were significantly associated with RPE in both cohorts. Age-related differences were observed, with lower pH and higher Pi/ATP ratios as well as lower D and f values in the late-middle-aged subjects. These findings are ascribed to age-related changes of fiber type composition, fiber size and vascularity. Interestingly, post exercise f was negatively associated with fat infiltration with the latter being significantly higher in late-middle-aged subjects. CSA of low back muscles remained unchanged, while CSA of inner back muscle as well as mean T2 at rest were associated with maximum force capacity. Overall, applying the proposed MR approach provides evidence of age-related changes in several muscle tissue characteristics and gives new insights into the physiological processes that take place during aging.

  16. Age-related structural and functional changes in the cochlear nucleus.

    Science.gov (United States)

    Frisina, Robert D; Walton, Joseph P

    2006-01-01

    Presbycusis - age-related hearing loss - is a key communication disorder and chronic medical condition of our aged population. The cochlear nucleus is the major site of projections from the auditory portion of the inner ear. Relative to other levels of the peripheral and central auditory systems, relatively few studies have been conducted examining age-related changes in the cochlear nucleus. The neurophysiological investigations suggest declines in glycine-mediated inhibition, reflected in increased firing rates in cochlear nucleus neurons from old animals relative to young adults. Biochemical investigations of glycine inhibition in the cochlear nucleus are consistent with the functional aging declines of this inhibitory neurotransmitter system that affect complex sound processing. Anatomical reductions in neurons of the cochlear nucleus and their output pathways can occur due to aging changes in the brain, as well as due to age-dependent plasticity of the cochlear nucleus in response to the age-related loss of inputs from the cochlea, particularly from the basal, high-frequency regions. Novel preventative and curative biomedical interventions in the future aimed at alleviating the hearing loss that comes with age, will likely emanate from increasing our knowledge and understanding of its neural and molecular bases. To the extent that this sensory deficit resides in the central auditory system, including the cochlear nucleus, future neural therapies will be able to improve hearing in the elderly.

  17. Age-related changes in the function and structure of the peripheral sensory pathway in mice.

    Science.gov (United States)

    Canta, Annalisa; Chiorazzi, Alessia; Carozzi, Valentina Alda; Meregalli, Cristina; Oggioni, Norberto; Bossi, Mario; Rodriguez-Menendez, Virginia; Avezza, Federica; Crippa, Luca; Lombardi, Raffaella; de Vito, Giuseppe; Piazza, Vincenzo; Cavaletti, Guido; Marmiroli, Paola

    2016-09-01

    This study is aimed at describing the changes occurring in the entire peripheral nervous system sensory pathway along a 2-year observation period in a cohort of C57BL/6 mice. The neurophysiological studies evidenced significant differences in the selected time points corresponding to childhood, young adulthood, adulthood, and aging (i.e., 1, 7, 15, and 25 months of age), with a parabolic course as function of time. The pathological assessment allowed to demonstrate signs of age-related changes since the age of 7 months, with a remarkable increase in both peripheral nerves and dorsal root ganglia at the subsequent time points. These changes were mainly in the myelin sheaths, as also confirmed by the Rotating-Polarization Coherent-Anti-stokes-Raman-scattering microscopy analysis. Evident changes were also present at the morphometric analysis performed on the peripheral nerves, dorsal root ganglia neurons, and skin biopsies. This extensive, multimodal characterization of the peripheral nervous system changes in aging provides the background for future mechanistic studies allowing the selection of the most appropriate time points and readouts according to the investigation aims. PMID:27459934

  18. Structural, biochemical, cellular, and functional changes in skeletal muscle extracellular matrix with aging

    DEFF Research Database (Denmark)

    Kragstrup, T W; Kjaer, M; Mackey, A L

    2011-01-01

    . Structural changes include an increase in the collagen concentration, a change in the elastic fiber system, and an increase in fat infiltration of skeletal muscle. Biochemical changes include a decreased turnover of collagen with potential accumulation of enzymatically mediated collagen cross...

  19. Quantification of age-related changes in the structure model type and trabecular thickness of human tibial cancellous

    DEFF Research Database (Denmark)

    Ding, Ming; Hvid, I

    2000-01-01

    traditionally been measured using model-based histomorphometric methods on two-dimensional (2-D) sections. However, no quantitative study has been published based on three-dimensional (3-D) methods on the age-related changes in structure model type and trabecular thickness for human peripheral (tibial......Structure model type and trabecular thickness are important characteristics in describing cancellous bone architecture. It has been qualitatively observed that a radical change of trabeculae from plate-like to rod-like occurs in aging, bone remodeling, and osteoporosis. Thickness of trabeculae has......, structure model type and trabecular thickness were quantified by means of novel 3-D methods. Structure model type was assessed by calculating the structure model index (SMI). The SMI was quantified based on a differential analysis of the triangulated bone surface of a structure. This technique allows...

  20. Changes in microRNAs expression are involved in age-related atrial structural remodeling and atrial fibrillation

    Institute of Scientific and Technical Information of China (English)

    XU Guo-jun; GAN Tian-yi; TANG Bao-peng; CHEN Zu-heng; Mahemuti Ailiman; ZHOU Xian-hui; JIANG Tao

    2013-01-01

    Background Small noncoding microRNAs regulate gene expression in cardiac development and disease and have been implicated in the aging process and in the regulation of extracellular matrix proteins.However,their role in age-related cardiac remodeling and atrial fibrillation (AF) was not well understood.The present study was designed to decipher molecular mechanisms underlying age-related atrial structural remodeling and AF.Methods Three groups of dogs were studied:adult and aged dogs in sinus rhythm and with persistent AF induced by rapid atrial pacing.The expressions of microRNAs were measured by quantitative real-time polymerase chain reaction.Pathohistological and ultrastructural changes were tested by light and electron microscopy.Apoptosis index of myocytes was detected by TUNEL.Results Samples of atrial tissue showed the abnormal pathohistological and ultrastructural changes,the accelerated fibrosis,and apoptosis with aging and/or in AF dogs.Compared to the adult group,the expressions of microRNAs-21 and -29 were significantly increased,whereas the expressions of microRNAs-1 and-133 showed obvious downregulation tendency in the aged group.Compared to the aged group,the expressions of microRNAs-1,-21,and-29 was significantly increased in the old group in AF; contrastingly,the expressions of microRNA-133 showed obvious downregulation tendency.Conclusion These multiple aberrantly expressed microRNAs may be responsible for modulating the transition from adaptation to pathological atrial remodeling with aging and/or in AF.

  1. Aging changes in the face

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/004004.htm Aging changes in the face To use the sharing ... Changes in face with age References Brodie SE. Aging and disorders of the eye. In: Fillit HM, ...

  2. Changes in ground beetle diversity and community composition in age structured forests (Coleoptera, Carabidae

    Directory of Open Access Journals (Sweden)

    Kathryn Riley

    2011-11-01

    Full Text Available We examined diversity, community composition, and wing-state of Carabidae as a function of forest age in Piedmont North Carolina. Carabidae were collected monthly from 396 pitfall traps (12×33 sites from March 2009 through February 2010, representing 5 forest age classes approximately 0, 10, 50, 85, and 150 years old. A total of 2,568 individuals, representing 30 genera and 63 species, were collected. Carabid species diversity, as estimated by six diversity indices, was significantly different between the oldest and youngest forest age classes for four of the six indices. Most carabid species were habitat generalists, occurring in all or most of the forest age classes. Carabid species composition varied across forest age classes. Seventeen carabid species were identified as potential candidates for ecological indicators of forest age. Non-metric multidimensional scaling (NMDS showed separation among forest age classes in terms of carabid beetle community composition. The proportion of individuals capable of flight decreased significantly with forest age.

  3. Seasonal and age related changes in size of reproductive structures of red deer hinds (Cervus elaphus

    Directory of Open Access Journals (Sweden)

    Rolf Langvatn

    1992-10-01

    Full Text Available Morphometric studies of uteri, ovary weights, and follicle diameters were carried out to investigate possible methodological applications. Size and anatomical appearance of the uterus varied with age and phase in the estrous cycle, both in parous and nulliparous females. The uterus thus may provide valuable information on reproductive status for known-aged animals. Weight of ovaries increased in young, but declined in old females, showing significant covariance with body weight in young and prime ages. Ovary weights increased from low levels shortly after parturition to a maximum towards the end of the gestation period. Ovaries containing a corpus luteum were heavier than those without. Compared to ovary weights, mean diameter of largest ovarian follicle varied in an opposite pattern during the yearly cycle. Maximum follicle diameter was largest in non-ovulated females. Weight of ovaries and follicle size appear to be of limited value as criteria in analysis of reproductive status and performance.

  4. Age-related changes in vascular structure and function Determinants and cardiovascular risk

    NARCIS (Netherlands)

    F.U.S. Mattace Raso (Francesco)

    2005-01-01

    textabstractArterial stiffness is one of the characteristics of vascular aging. Increases in pulse pressure, which re.ects an increase in the stiffness of the large arteries, are associated with elevated C-reactive protein levels. This may suggest a role of in.ammation in the development of arterial

  5. Age-related skin changes

    Directory of Open Access Journals (Sweden)

    Božanić Snežana

    2012-01-01

    Full Text Available Age-related skin changes can be induced by chronological ageing, manifested in subcutaneous fat reduction, and photo-ageing eliciting increased elastotic substance in the upper dermis, destruction of its fibrilar structure, augmented intercellular substance and moderate inflammatory infiltrate. Forty-five biopsy skin samples of the sun-exposed and sun-protected skin were analyzed. The patients were both males and females, aged from 17 to 81 years. The thickness of the epidermal layers and the number of cellular living layers is greater in younger skin. The amount of keratohyaline granules is enlarged in older skin. Dermoepidermal junction is flattened and the presence of elastotic material in the dermis is pronounced with age. The amount of inflammatory infiltrate is increased, the fibrous trabeculae are thickened in older skin and the atrophy of the hypodermis is observed. Chronological ageing alters the fibroblasts metabolism by reducing their life span, capacity to divide and produce collagen. During ageing, the enlargement of collagen fibrils diminishes the skin elasticity.

  6. Aging changes in the lungs

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/004011.htm Aging changes in the lungs To use the sharing ... out (exhaled). Watch this video about: Gas exchange AGING CHANGES IN YOUR BODY AND THEIR AFFECTS ON ...

  7. Aging changes in body shape

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003998.htm Aging changes in body shape To use the sharing ... and both sexes. Height loss is related to aging changes in the bones, muscles, and joints. People ...

  8. Aging changes in the kidneys

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/004010.htm Aging changes in the kidneys and bladder To use ... in the reproductive system can affect bladder control. Aging Changes and Their Effects on the Kidneys and ...

  9. Aging changes in hormone production

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/004000.htm Aging changes in hormone production To use the sharing ... that produce hormones are controlled by other hormones. Aging also changes this process. For example, an endocrine ...

  10. Age-related oral changes.

    LENUS (Irish Health Repository)

    Mckenna, Gerald

    2010-10-01

    Age-related oral changes are seen in the oral hard and soft tissues as well as in bone, the temporomandibular joints and the oral mucosa. As older patients retain their natural teeth for longer, the clinical picture consists of normal physiological age changes in combination with pathological and iatrogenic effects. Clinical Relevance: With an ageing population retaining more of its natural teeth for longer, dental professionals should expect to observe oral age changes more frequently.

  11. Stuies on histological changing rice during aging

    Institute of Scientific and Technical Information of China (English)

    Qian haifeng; Houyiming; Yao huiyuan

    2001-01-01

    The changing of rice endosperm cell during aging was inspected and analyzed by tissue section method in this paper, which was considered as the main causation of the descending of the eating quality of aged rice. A new effective method of improving the eating quality of aged rice was also carried out through enzymatic treatment which was based on the changing of histological structure of aged rice.

  12. Aging changes in skin

    Science.gov (United States)

    ... areas. Changes in the connective tissue reduce the skin's strength and elasticity. This is known as elastosis. It is more ... chemicals Indoor heating Sunlight can cause: Loss of elasticity ... growths (keratoacanthomas) Pigment changes such as liver spots ...

  13. Aging changes in the breast

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003999.htm Aging changes in the breast To use the sharing ... chap 18. Minaker KL. Common clinical sequelae of aging. In: Goldman L, Schafer AI, eds. Goldman's Cecil ...

  14. Aging changes in the senses

    Science.gov (United States)

    ... ency/article/004013.htm Aging changes in the senses To use the sharing features on this page, ... enable JavaScript. As you age, the way your senses (hearing, vision, taste, smell, touch) give you information ...

  15. Future Changes in Age and Household Patterns

    DEFF Research Database (Denmark)

    Højbjerg Jacobsen, Rasmus; Hougaard Jensen, Svend E.

    2014-01-01

    status, we show that, based on a point forecast, the fiscal impact of changes in household structures amounts to an annual negative effect of 0.5% of GDP, and the effect of changes in age structures is forecast to worsen the public budget by 3.7% of GDP per year. While being subject to a considerable...

  16. Consumption-Driven Environmental Impact and Age Structure Change in OECD Countries: A Cointegration-STIRPAT Analysis

    Directory of Open Access Journals (Sweden)

    Brantley Liddle

    2011-05-01

    Full Text Available This paper examines two environmental impacts for which population has a substantial demonstrated influence: transport carbon emissions and residential electricity consumption. It takes as its starting point the STIRPAT framework and disaggregates population into four key age groups: 20-34, 35-49, 50-69, and 70 and older. Population age structure's influence was significant and varied across cohorts, and its profile was different for two dependent variables. For transport, young adults (20-34 were intensive, whereas the other cohorts had negative coefficients. For residential electricity consumption, age structure had a U-shaped impact: the youngest and oldest had positive coefficients, while the middle cohorts had negative coefficients.

  17. Scoping the Impact of Changes in Population Age-Structure on the Future Burden of Foodborne Disease in The Netherlands, 2020–2060

    Directory of Open Access Journals (Sweden)

    Arie H. Havelaar

    2013-07-01

    Full Text Available A demographic shift towards a larger proportion of elderly in the Dutch population in the coming decades might change foodborne disease incidence and mortality. In the current study we focused on the age-specific changes in the occurrence of foodborne pathogens by combining age-specific demographic forecasts for 10-year periods between 2020 and 2060 with current age-specific infection probabilities for Campylobacter spp., non-typhoidal Salmonella, hepatitis A virus, acquired Toxoplasma gondii and Listeria monocytogenes. Disease incidence rates for the former three pathogens were estimated to change marginally, because increases and decreases in specific age groups cancelled out over all ages. Estimated incidence of reported cases per 100,000 for 2060 mounted to 12 (Salmonella, 51 (Campylobacter, 1.1 (hepatitis A virus and 2.1 (Toxoplasma. For L. monocytogenes, incidence increased by 45% from 0.41 per 100,000 in 2011 to 0.60 per 100,000. Estimated mortality rates increased two-fold for Salmonella and Campylobacter to 0.5 and 0.7 per 100,000, and increased by 25% for Listeria from 0.06 to 0.08. This straightforward scoping effort does not suggest major changes in incidence and mortality for these food borne pathogens based on changes in de population age-structure as independent factor. Other factors, such as changes in health care systems, social clustering and food processing and preparation, could not be included in the estimates.

  18. Age-related structural changes in the myenteric nervous plexus ganglion along the anterior wall of the proximal human duodenum: A morphometric analysis

    Directory of Open Access Journals (Sweden)

    Mandić Predrag

    2013-01-01

    Full Text Available Background/Aim. Aging is one of the most complex biological processes which probably affect structure and function of the enteric nerve system. However, there is not much available information on this topic, particularly in humans. The aim of this study was to investigate the influence of aging on the structure of the myenteric ganglia in the anterior wall of the human proximal duodenum. Methods. We examined the myenteric ganglia in the proximal duodenal anterior wall specimens obtained from 30 cadaver persons aged from 20 to 84 years. Tissue samples were classified into three age groups: 20-44, 45-64 and 65-84 years. After standard histological preparation, specimens were stained with HE, Cresyl Violet and AgNO3. Morphometric analysis of all the specimens, using a multipurpose test system M42, was performed. The data were subjected to the ttest. Results. The myenteric ganglia of very old humans contains an empty space, i.e. the respective parts of ganglia show a decreased number of neuron as compared to younger population. The average number of neuron per cm2 of the duodenum in the youngest people (20-44 years was 69,370 ± 1,750.00, in the people aged 45-64 years 69,211 ± 1,573.33, and in the oldest persons (65-84 years 57,951 ± 1,291.52. The loss of neurons in the oldest persons was 16.46%. The applied statistic test demonstrated a significant difference between the observed groups (p < 0.0001. Conclusion. Aging does not induce changes in size and surface of neurons in the ganglia, but it decreases the number of neurons. The nerve structures in the elderly are partly emptied of bodies of nerve cells (“empty ganglions”, which indicates the existence of changed myenteric ganglia in the duodenum. These changes could be related to the duodenum motility disorder associated with aging.

  19. Age changes in human bone: an overview

    Energy Technology Data Exchange (ETDEWEB)

    Sharpe, W.D.

    1977-12-03

    The human skeleton steadily changes structure and mass during life because of a variety of internal and external factors. Extracellular substance and bone cells get old, characteristic structural remodeling occurs with age and these age-related changes are important in the discrimination between pathological and physiological changes. Perhaps 20 percent of the bone mass is lost between the fourth and the ninth decades, osteoblasts function less efficiently and gradual loss of bone substance is enhanced by delayed mineralization of an increased surface area of thin and relatively less active osteoid seams. After the fifth decade, osteoclasia and the number of Howship's lacunae increase, and with age, the number of large osteolytic osteocytes increases as the number of small osteocytes declines and empty osteocyte lacunae become more common. The result is greater liability to fracture and diminished healing or replacement of injured bone.

  20. Aging changes in organs - tissue - cells

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/004012.htm Aging changes in organs - tissue - cells To use the ... lose some function as you age during adulthood. Aging changes occur in all of the body's cells, ...

  1. Specific renal parenchymal-derived urinary extracellular vesicles identify age-associated structural changes in living donor kidneys

    OpenAIRE

    Anne E. Turco; Lam, Wing; Rule, Andrew D.; Denic, Aleksandar; Lieske, John C.; Miller, Virginia M.; Larson, Joseph J.; Kremers, Walter K.; Jayachandran, Muthuvel

    2016-01-01

    Non-invasive tests to identify age and early disease-associated pathology within the kidney are needed. Specific populations of urinary extracellular vesicles (EVs) could potentially be used for such a diagnostic test. Random urine samples were obtained from age- and sex-stratified living kidney donors before kidney donation. A biopsy of the donor kidney was obtained at the time of transplantation to identify nephron hypertrophy (larger glomerular volume, cortex per glomerulus and mean profil...

  2. Structural aging program status report

    Energy Technology Data Exchange (ETDEWEB)

    Naus, D.J.; Oland, C.B. [Oak Ridge National Lab., TN (United States); Ellingwood, B. [Johns Hopkins Univ., Baltimore, MD (United States)] [and others

    1995-04-01

    Research is being conducted at the Oak Ridge National Laboratory (ORNL) under U.S. Nuclear Regulatory Commission (USNRC) sponsorship to address aging management of safety-related concrete structures. Documentation is being prepared to provide the USNRC with potential structural safety issues and acceptance criteria for use in continued service evaluations of nuclear power plants. Program accomplishments have included development of the Structural Materials Information Center containing data and information of the time variation of 144 material properties under the influence of pertinent environmental stressors of aging factors, performance assessments of reinforced concrete structures in several United Kingdom nuclear power facilities, evaluation of European and North American repair practices for concrete, an evaluation of factors affecting the corrosion of metals embedded in concrete, and application of the time-dependent reliability methodology to reinforced concrete flexure and shear structural elements to investigate the role of in-service inspection and repair on their probability of failure.

  3. Structural aging program status report

    International Nuclear Information System (INIS)

    Research is being conducted at the Oak Ridge National Laboratory under Nuclear Regulatory Commission (USNRC) sponsorship to address aging management of safety-related concrete structures. Documentation is being prepared to provide the USNRC with potential structural safety issues and acceptance criteria for use in continued service evaluations of nuclear power plants. Program accomplishments have included development of the Structural Materials Information Center containing data and information on the time variation of 144 material properties under the influence of pertinent environmental stressors or aging factors, performance assessments of reinforced concrete structures in several United Kingdom nuclear power facilities, evaluation of European and North American repair practices for concrete, an evaluation of factors affecting the corrosion of metals embedded in concrete, and application of the time-dependent reliability methodology to reinforced concrete flexure and shear structural elements to investigate the role of in-service inspection and repair on their probability of failure

  4. Aging changes in the male reproductive system

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/004017.htm Aging changes in the male reproductive system To use ... sharing features on this page, please enable JavaScript. Aging changes in the male reproductive system may include ...

  5. Organisational Structure & Change

    Science.gov (United States)

    National Centre for Vocational Education Research (NCVER), 2006

    2006-01-01

    Structural change is seen as a way to meet the challenges of the future that face many organisations. While some writers agree that broad-ranging structural change may not always transform an organisation or enhance its performance, others claim that innovation will be a major source of competitive advantage to organisations, particularly when…

  6. Bottom up modeling of the connectome: Linking structure and function in the resting brain and their changes in aging.

    OpenAIRE

    Nakagawa, Tristan T.; Jirsa, Viktor K.; Spiegler, Andreas; McIntosh, Anthony R.; Deco, Gustavo

    2013-01-01

    With the increasing availability of advanced imaging technologies, we are entering a new era of neuroscience. Detailed descriptions of the complex brain network enable us to map out a structural connectome, characterize it with graph theoretical methods, and compare it to the functional networks with increasing detail. To link these two aspects and understand how dynamics and structure interact to form functional brain networks in task and in the resting state, we use theore...

  7. Variation in mechanical properties of 4340 steel owing to thermal aging and study of corresponding change in structure sensitive magnetic permeability

    International Nuclear Information System (INIS)

    The eddy current testing has been utilized to study the structure sensitive magnetic properties and electrical conductivity of tempered and roll-aged samples of steel as well as non-ferrous alloys such as aluminum. The major objective is to detect the aging and auto-tempering conditions in the steels and non-ferrous alloys nondestructively via eddy current inspection. Phasec 3D was used for eddy current inspection of the samples of steel and aluminum which had been quenched, normalized, annealed, aged and tempered in a Muffle furnace. The optical microscope was used to study the microstructures with computer software 'Microstructure Characterizer' for the multiphase analysis. The settings of Phasec 3D were optimized to get the maximum signal resolution maintaining readable display. Frequency, gain, phase angle are among the major parameters of Phasec 3D which were used to study the heat treatment conditions which were applied to steel and aluminum samples. The non-ferrous alloys such as aluminum were studied on the basis of their conductivity but all other ferrous alloys were studied for their change in magnetic permeability. It is clear from the results that eddy current testing can not only be used for microstructure characterization of low carbon steels and detection of heat treatment conditions but also for an important phenomena 'auto-tempering' of quench-hardened steels and for the detection of aging of rolled and cold worked steels. (author)

  8. Structural Neuroimaging in Aging and Alzheimer's Disease

    NARCIS (Netherlands)

    Vernooij, Meike W.; Smits, Marion

    2012-01-01

    The role of structural neuroimaging in the diagnosis of Alzheimer's disease (AD) is becoming increasingly important. As a consequence, a basic understanding of what are normal brain changes in aging is key to be able to recognize what is abnormal. The first part of this article discusses normal vers

  9. 养老模式转型与老年群体的应对策略%Countermeasure for the Aged Group in the Changing Period of Aged Support Structure

    Institute of Scientific and Technical Information of China (English)

    王光荣

    2012-01-01

    我国已进入老龄化社会,传统的家庭养老模式不堪重负,由机构养老、社区养老和居家养老组成的社会养老体系正在探索中。在这养老模式变化和调整时期,老年群体应树立积极养老的观念,提早备老,提高自助养老、互助养老和受助养老等素质,从而增进养老的质量,促进社会化养老体系建设。%China has entered the aging society, so the traditional tamily care mode become unable. Social support system based on pension institutions, community and home is in developing period. In this aged support structure changing and adjusting period, the aged groups should foster a positive nursing concept, make advance preparation for aging and improve pension notions such as self-help, mutual support and recipients of pension in order to enhance the care quality and promote the social aged support system.

  10. Change in Business Structure

    Data.gov (United States)

    Department of Veterans Affairs — Provides information on whether a company’s change in business structure affects its Data Universal Numbering System (DUNS) Number and its Vendor Information Pages...

  11. Changing how we view aging.

    Science.gov (United States)

    Holland, Jimmie; Greenstein, Mindy

    2015-05-01

    It is time for medicine, particularly geriatric medicine, to incorporate an understanding of how the psychological aspects of aging interact with cancer. The impact has both negative elements--for example, the added stresses of other losses or comorbid ailments that come with age--and positive elements, particularly a lifetime of honing character strengths on which to draw during a challenging time. PMID:25944028

  12. Aging changes in vital signs

    Science.gov (United States)

    ... to wear layers of clothing to feel warm. Aging decreases your ability to sweat. You may have difficulty telling when you are becoming overheated. This puts you at high risk of overheating ( heat stroke ). You can also be at risk for dangerous ...

  13. Aging changes in the bones - muscles - joints

    Science.gov (United States)

    ... muscles and tendons, rather than changes in the nerves. Decreased knee jerk or ankle jerk can occur. Some changes, such as a positive Babinski's reflex , are not a normal part of aging. Involuntary ...

  14. Normal and aging hair biology and structure 'aging and hair'.

    Science.gov (United States)

    Goodier, Molly; Hordinsky, Maria

    2015-01-01

    Much like an individual's hairstyle, hair fibers along the scalp see a number of changes over the course of one's lifetime. As the decades pass, the shine and volume synonymous with youthful hair may give way to thin, dull, and brittle hair commonly associated with aging. These changes are a result of a compilation of genetic and environmental elements influencing the cells of the hair follicle, specifically the hair follicle stem cells and melanocytes. Telomere shortening, decrease in cell numbers, and particular transcription factors have all been implicated in this process. In turn, these molecular alterations lead to structural modifications of the hair fiber, decrease in melanin production, and lengthening of the telogen phase of the hair cycle. Despite this inevitable progression with aging, there exists an array of treatments such as light therapy, minoxidil, and finasteride which have been designed to mitigate the effects of aging, particularly balding and thinning hair. Although each works through a different mechanism, all aim to maintain or potentially restore the youthful quality of hair. PMID:26370639

  15. Ageing management for systems, structures and components

    International Nuclear Information System (INIS)

    During operation, ageing will influence the quality of systems, structures and components (SSC). Experts make a distinction between the phenomena of conceptional ageing, technological ageing and physical ageing. The quality of SSC may be influenced by conceptional ageing, quality, technological or physical ageing. The contribution outlines the preconditions for a comprehensive, standardized ageing management of nuclear power stations in the Federal Republic of Germany. (orig.)

  16. An age structured demographic model of technology

    CERN Document Server

    Mercure, J -F

    2013-01-01

    At the heart of technology transitions lie complex processes of technology choices. Understanding and planning sustainability transitions requires modelling work, which necessitates a theory of technology substitution. A theoretical model of technological change and turnover is presented, intended as a methodological paradigm shift from widely used conventional modelling approaches such as cost optimisation. It follows the tradition of evolutionary economics and evolutionary game theory, using ecological population growth dynamics to represent the evolution of technology populations in the marketplace, with substitutions taking place at the level of the decision-maker. Extended to use principles of human demography or the age structured evolution of species in interacting ecosystems, this theory is built from first principles, and through an appropriate approximation, reduces to a form identical to empirical models of technology diffusion common in the technology transitions literature. Using an age structure...

  17. AGE WISE HISTOMORPHOLOGICAL CHANGES IN HUMAN LIVER

    Directory of Open Access Journals (Sweden)

    Tribeni

    2015-11-01

    Full Text Available CONTEXT: Hepato cellular carcinoma (HCC results in between 2.5 lakhs to 1million deaths globally per annum. Liver transplantation nowadays is a well accepted treatment option for end-stage liver disease and acute liver failure. AIMS: Keeping this concept in view, a study was conducted in the Guwahati Zone of Northeast India, to compare the histomorphological features of the human liver in different age groups. SETTING AND DESIGN: Apparently healthy livers were obtained from 21 subjects on whom medicolegal post-mortems had been performed. Their ages varied from newborn to 90 years. Subjects were divided into 3 groups. 7 specimens were taken from each group. (1 Pediatric (2 Adult (3 Old age. METHODS AND MATERIALS: In all the above age groups, immediately after removal of the livers, they were washed in normal saline, dried with blotting paper and weighed in an electronic weighing machine. Sections of liver were fixed, processed, cut and stained with Harris Haematoxylin and Eosin stain. RESULTS: The liver loses weight from 50 years onwards. There appears to be racial and environmental differences in the change in liver weight in old age. Autopsy studies show a diminution of nearly 46% in liver weight between the 3rd and 10th decades of life. The liver decreases in size with age. The hepatocytes are radially disposed in the liver lobule. They are piled up, forming a layer one cell thick (except in young children in a fashion similar to the bricks of a wall. These plates are directed from the periphery of the lobule to its centre and anastomose freely forming a complex labyrinthine and sponge-like structure. CONCLUSIONS: From the findings in the present study it can be concluded that: 1. Nowadays, the measurement of liver volume has gained practical use in relation to liver transplantation. 2. We have compared the histomorphology of adult liver with a child. The findings in both the groups are very similar. This feature is important, since in

  18. Aging changes in hair and nails

    Science.gov (United States)

    ... Hair color is due to a pigment called melanin , which hair follicles produce. Follicles are structures in the skin that make and grow hair. With aging, the follicles make less melanin, and this causes gray hair. Graying often begins ...

  19. Aging changes in the nervous system

    Science.gov (United States)

    ... article/004023.htm Aging changes in the nervous system To use the sharing features on this page, please enable JavaScript. The brain and nervous system are your body's central control center. They control ...

  20. [Age-related changes of sensory system].

    Science.gov (United States)

    Iwamoto, Toshihiko; Hanyu, Haruo; Umahara, Takahiko

    2013-10-01

    Pathological processes usually superimpose on physiological aging even in the sensory system including visual, hearing, olfactory, taste and somatosensory functions. Representative changes of age-related changes are presbyopia, cataracts, and presbyacusis. Reduced sense of smell is seen in normal aging, but the prominent reduction detected by the odor stick identification test is noticed especially in early stage of Alzheimer or Parkinson disease. Reduced sense of taste is well-known especially in salty sense, while the changes of sweet, bitter, and sour tastes are different among individuals. Finally, deep sensation of vibration and proprioception is decreased with age as well as superficial sensation (touch, temperature, pain). As a result, impaired sensory system could induce deterioration of the activities of daily living and quality of life in the elderly. PMID:24261198

  1. Changing Retirement Age: Ups and Downs.

    Science.gov (United States)

    Wiatrowski, William J.

    2001-01-01

    In recent years, legislative changes, new types of retirement plans, and increases in life expectancy have led to differences in retirement ages. More older adults continue to work. The traditional model of social security, savings, and employer retirement benefits is changing. (Contains 31 notes and references.) (SK)

  2. IIASA's Population Project: Aging and Changing Lifestyles

    OpenAIRE

    Rogers, A

    1982-01-01

    Low fertility levels in IIASA countries are creating aging populations whose demands for health care and income maintenance (social security) will increase to unprecedented levels, thereby calling forth policies that will seek to promote increased family care and worklife flexibility. The Population Project will examine current patterns of population aging and changing lifestyles in IIASA countries, project the needs for health and income support that such patterns are likely to generate duri...

  3. Sex- and age-related differences in femoral neck cross-sectional structural changes in mainland Chinese men and women measured using dual-energy X-ray absorptiometry.

    Science.gov (United States)

    Gong, Jian; Tang, Min; Guo, Bin; Shang, JingJie; Tang, Yongjin; Xu, Hao

    2016-02-01

    We investigated age-related changes in estimated bone strength and cross-sectional structure of the femoral neck (FN) in mainland Chinese men and women (according to age and sex) using dual-energy X-ray absorptiometry (DXA). A total of 3855 healthy adults (2713 women, 1142 men; ages 25-91years) were analyzed by FN bone mineral density (BMD) assessment and hip structural/strength analysis (HSA), including cross-sectional moment of inertia (CSMI), cross-sectional area (CSA), section modulus (Z), periosteal diameter (PD), endocortical diameter (ED), and cortical thickness (CT) using DXA. HSA differences between age and sex groups were adjusted for body weight, height and FN BMD. Trends according to age were estimated by linear regression analysis. There was no inverse correlation between HSA parameters and age in young adults. Some HSA parameters (CSMI, CSA, Z, CT) decreased significantly with age, whereas PD and ED increased significantly. Older adults had less estimated bone strength and CT and higher PD and ED (pyoung adults. Men had greater increases in PD and ED than women across all ages. FN strength decreases with age in both sexes, caused by FN cross-sectional structural deterioration. Indirect comparison of our data with those from other populations showed less age-related FN periosteal apposition in Chinese than Caucasian men, but similar amounts in women. This may partly explain different male/female hip fracture rates among ethnic groups. Chinese men have more structural disadvantages regarding FN geometry during aging than Caucasian men, possibly conferring added susceptibility to hip fracture.

  4. Age-Related White Matter Changes

    Directory of Open Access Journals (Sweden)

    Yun Yun Xiong

    2011-01-01

    Full Text Available Age-related white matter changes (WMC are considered manifestation of arteriolosclerotic small vessel disease and are related to age and vascular risk factors. Most recent studies have shown that WMC are associated with a host of poor outcomes, including cognitive impairment, dementia, urinary incontinence, gait disturbances, depression, and increased risk of stroke and death. Although the clinical relevance of WMC has been extensively studied, to date, only very few clinical trials have evaluated potential symptomatic or preventive treatments for WMC. In this paper, we reviewed the current understanding in the pathophysiology, epidemiology, clinical importance, chemical biomarkers, and treatments of age-related WMC.

  5. Change and aging senescence as an adaptation.

    Directory of Open Access Journals (Sweden)

    André C R Martins

    Full Text Available Understanding why we age is a long-lived open problem in evolutionary biology. Aging is prejudicial to the individual, and evolutionary forces should prevent it, but many species show signs of senescence as individuals age. Here, I will propose a model for aging based on assumptions that are compatible with evolutionary theory: i competition is between individuals; ii there is some degree of locality, so quite often competition will be between parents and their progeny; iii optimal conditions are not stationary, and mutation helps each species to keep competitive. When conditions change, a senescent species can drive immortal competitors to extinction. This counter-intuitive result arises from the pruning caused by the death of elder individuals. When there is change and mutation, each generation is slightly better adapted to the new conditions, but some older individuals survive by chance. Senescence can eliminate those from the genetic pool. Even though individual selection forces can sometimes win over group selection ones, it is not exactly the individual that is selected but its lineage. While senescence damages the individuals and has an evolutionary cost, it has a benefit of its own. It allows each lineage to adapt faster to changing conditions. We age because the world changes.

  6. Preventing adverse changes of work with age.

    Science.gov (United States)

    Welford, A T

    1988-01-01

    Many people who change their jobs in middle age have been found to move to less skilled and lower paid work. Two methods of preventing this are discussed. First, training by methods designed to take account of learning difficulties in those past normal apprenticeship age has, when sensitively applied, been successful in equipping people with new skills. Second, applying principles of ergonomics--"fitting the job to the worker"--could often remove key difficulties for older workers and thus prevent the need for moves resulting from failing capacity. This could also open up a wider range of potential jobs for those who have to move by reason of redundancy or technological change. It is emphasized that both the training and ergonomic approaches need to be based on, and can contribute significantly to, fundamental research on performance in relation to age.

  7. Age structure of population; 1 : 750 000

    International Nuclear Information System (INIS)

    The main aim is to present the population structure by gender and age in the districts and regions of Slovakia. The index of femininity expresses the number of women per 1,000 men. There are only two districts with prevalence of men in Slovakia (969 women in Namestovo and 999 women in Sabinov). On the other side, the distinct prevalence of women is in the districts of the Capital Bratislava, in especial the district I (1,190) as the consequence of higher representation of old age categories (the share of women increases with age). The age structure as such is expressed by the age pyramid, which characterises the representation of the single age categories or types of population reproduction. Three types of age structures and reproduction were recognised: amplified reproduction - the progressive type (for instance, Namestovo, Kezmarok), simple reproduction - the stationary type (for instance, Vranov nad Toplou), and insufficient reproduction - the regressive type (for instance, Medzilaborce and Bratislava I). (authors)

  8. Age-related changes in the structure and function of prefrontal cortex-amygdala circuitry in children and adolescents: a multi-modal imaging approach.

    Science.gov (United States)

    Swartz, Johnna R; Carrasco, Melisa; Wiggins, Jillian Lee; Thomason, Moriah E; Monk, Christopher S

    2014-02-01

    The uncinate fasciculus is a major white matter tract that provides a crucial link between areas of the human brain that underlie emotion processing and regulation. Specifically, the uncinate fasciculus is the major direct fiber tract that connects the prefrontal cortex and the amygdala. The aim of the present study was to use a multi-modal imaging approach in order to simultaneously examine the relation between structural connectivity of the uncinate fasciculus and functional activation of the amygdala in a youth sample (children and adolescents). Participants were 9 to 19years old and underwent diffusion tensor imaging (DTI) and functional magnetic resonance imaging (fMRI). Results indicate that greater structural connectivity of the uncinate fasciculus predicts reduced amygdala activation to sad and happy faces. This effect is moderated by age, with younger participants exhibiting a stronger relation. Further, decreased amygdala activation to sad faces predicts lower internalizing symptoms. These results provide important insights into brain structure-function relationships during adolescence, and suggest that greater structural connectivity of the uncinate fasciculus may facilitate regulation of the amygdala, particularly during early adolescence. These findings also have implications for understanding the relation between brain structure, function, and the development of emotion regulation difficulties, such as internalizing symptoms. PMID:23959199

  9. Changes in infestation rate and age structure of Dermanyssus hirundinis and Ornithonyssus sylviarum (Acarina) during nidification and breeding period of penduline tit.

    Science.gov (United States)

    Masán, P

    1997-11-01

    Populations of 2 parasitic mites, Dermanyssus hirundinis (Hermann) (63,169 collected individuals) and Ornithonyssus sylviarum (Canestrini et Fanzago) (3,425 collected individuals), in 305 penduline tit, Remiz pendulinus L., nests were studied in 1993 and 1994. The nests were divided into 4 groups: nests without eggs, nests with eggs, nests with nestlings, and nests just after fledging. The average percentage of infested nests increased from the nests without eggs to the nests after fledging (at 20% in both years of investigation), and the increase of mite abundance was exponential. Presence of nestlings in the nests stimulated intensive reproduction of parasitic mites. An increasing infestation intensity in nests was observed during the host breeding period. The 2 mite species exhibited similar age structure patterns in the nests of all the groups and during the entire penduline tit breeding period as well. A decrease in the proportion of adult mites (mainly females) and an increase of nymphs (above all of protonymphs) occurred at the time of fledging and at the end of host breeding period. The percentage of the ovigerous females increased in the individual nests, but decreased during the breeding period of penduline tit. The quantitative parameters of D. hirundinis populations in the highly infested nests depended on the individual nidification and nidobiology of the host, whereas the qualitative parameters (age structure) of these populations depended more on abiotic factors and life strategy of the ectoparasite. PMID:9439114

  10. Age-related changes in task related functional network connectivity.

    Directory of Open Access Journals (Sweden)

    Jason Steffener

    Full Text Available Aging has a multi-faceted impact on brain structure, brain function and cognitive task performance, but the interaction of these different age-related changes is largely unexplored. We hypothesize that age-related structural changes alter the functional connectivity within the brain, resulting in altered task performance during cognitive challenges. In this neuroimaging study, we used independent components analysis to identify spatial patterns of coordinated functional activity involved in the performance of a verbal delayed item recognition task from 75 healthy young and 37 healthy old adults. Strength of functional connectivity between spatial components was assessed for age group differences and related to speeded task performance. We then assessed whether age-related differences in global brain volume were associated with age-related differences in functional network connectivity. Both age groups used a series of spatial components during the verbal working memory task and the strength and distribution of functional network connectivity between these components differed across the age groups. Poorer task performance, i.e. slower speed with increasing memory load, in the old adults was associated with decreases in functional network connectivity between components comprised of the supplementary motor area and the middle cingulate and between the precuneus and the middle/superior frontal cortex. Advancing age also led to decreased brain volume; however, there was no evidence to support the hypothesis that age-related alterations in functional network connectivity were the result of global brain volume changes. These results suggest that age-related differences in the coordination of neural activity between brain regions partially underlie differences in cognitive performance.

  11. White matter changes and word finding failures with increasing age.

    Directory of Open Access Journals (Sweden)

    Emmanuel A Stamatakis

    Full Text Available BACKGROUND: Increasing life expectancy necessitates the better understanding of the neurophysiological underpinnings of age-related cognitive changes. The majority of research examining structural-cognitive relationships in aging focuses on the role of age-related changes to grey matter integrity. In the current study, we examined the relationship between age-related changes in white matter and language production. More specifically, we concentrated on word-finding failures, which increase with age. METHODOLOGY/PRINCIPAL FINDINGS: We used Diffusion tensor MRI (a technique used to image, in vivo, the diffusion of water molecules in brain tissue to relate white matter integrity to measures of successful and unsuccessful picture naming. Diffusion tensor images were used to calculate Fractional Anisotropy (FA images. FA is considered to be a measure of white matter organization/integrity. FA images were related to measures of successful picture naming and to word finding failures using voxel-based linear regression analyses. Successful naming rates correlated positively with white matter integrity across a broad range of regions implicated in language production. However, word finding failure rates correlated negatively with a more restricted region in the posterior aspect of superior longitudinal fasciculus. CONCLUSIONS/SIGNIFICANCE: The use of DTI-MRI provides evidence for the relationship between age-related white matter changes in specific language regions and word finding failures in old age.

  12. AGE CHANGES IN HUMAN SKIN FROM 3 YEARS TO 75 YEARS OF AGE

    Directory of Open Access Journals (Sweden)

    Samiappan Manimegalai

    2015-12-01

    Full Text Available Background: Natural aging process is reflected by gradual changes in the structure of the skin. These changes become very marked in old age. The changes in the epidermis and dermis as age advances is reflected externally as wrinkling, dryness, loss of elasticity , thinning and tendency towards purpurae on minor injury. So the aim of this study is to measure the thickness of the epidermis. Materials and Methods: The study was done in skin specimens by grouping the individuals in 4 age groups namely Group A (3-20yrs, Group B (21-50yrs, Group C (51-65yrs and Group D (>65yrs.The specimens were stained with Haematoxylin and Eosin stain and the changes in the thickness of the epidermis was observed. Results: The epidermis was found to be thin in children from 3years of age. The thickness of the epidermis starts increasing in young individuals and is thick till 50 years of age. Then the thickness of the epidermis starts reducing and becomes very thin in older persons. Conclusion: As the average life expectancy is increasing, the aging of skin presents a growing problem for the dermatologists. The computer system for image processing and analysis has made possible, measuring the thickness of the epidermis. Human aging is characterized by a number of disorders like epidermolysis bullosa and phemphigus vulgaris affecting the structure of the skin. So it is necessary to study the normal changes that occur in the skin as age advances which predisposes to various disorders. The study is done among Indian population.

  13. Age Related Change in Thyroid Function

    Directory of Open Access Journals (Sweden)

    Shakila Rahman, Nasim Jahan, Nayma Sultana

    2012-12-01

    Full Text Available AbstractBackground: Thyroid hormones play a vital role in metabolism, sensitivity of tissues to other hormones and also in oxygen consumption of almost all cells of the body. However, mild to moderate decrease in function of thyroid gland may occur with advancing age even in apparently healthy elderly subjects.Objectives: To observe age related change in thyroid function status in apparently healthy elderly subjects in Bangladesh.Methods: This cross sectional study was carried out in the Department of Physiology, Sir Salimullah Medical College, Dhaka between 1st January 2011 and 31st December 2011. Sixty apparently healthy elderly subjects of both sexes aged 50 to 75 years were taken as study group. They were collected from Probin Nibash Hitoishi Shangha, Agargaon, Dhaka. In addition, 30 apparently healthy young adult subjects aged 20-40 years were included as control. For assessment of thyroid function, serum free thyroxine (FT4, free triiodothyronine (FT3 and thyroid stimulating hormone (TSH levels were estimated by ELISA method. Statistical analysis was done by one way ANOVA, Bonferroni test and Pearson’s Correlation Coefficient test as applicable.Results: In this study, mean serum free thyroxine (FT4 and free triiodothyronine (FT3 levels were significantly (p<0.001 lower and serum thyroid stimulating hormone (TSH level was significantly (p<0.001 higher in apparently healthy elderly subjects in comparison to those of the healthy young subjects. Again, serum FT4 and FT3 levels were negatively correlated whereas serum TSH level was positively correlated with age of the subjects.Conclusion: The present study revealed a progressive decrease in thyroid function with advancement of age.

  14. Age-Related Neurochemical Changes in the Vestibular Nuclei.

    Science.gov (United States)

    Smith, Paul F

    2016-01-01

    There is evidence that the normal aging process is associated with impaired vestibulo-ocular reflexes (VOR) and vestibulo-spinal reflexes, causing reduced visual acuity and postural instability. Nonetheless, the available evidence is not entirely consistent, especially with respect to the VOR. Some recent studies have reported that VOR gain can be intact even above 80 years of age. Similarly, although there is evidence for age-related hair cell loss and neuronal loss in Scarpa's ganglion and the vestibular nucleus complex (VNC), it is not entirely consistent. Whatever structural and functional changes occur in the VNC as a result of aging, either to cause vestibular impairment or to compensate for it, neurochemical changes must underlie them. However, the neurochemical changes that occur in the VNC with aging are poorly understood because the available literature is very limited. This review summarizes and critically evaluates the available evidence relating to the noradrenaline, serotonin, dopamine, glutamate, GABA, glycine, and nitric oxide neurotransmitter systems in the aging VNC. It is concluded that, at present, it is difficult, if not impossible, to relate the neurochemical changes observed to the function of specific VNC neurons and whether the observed changes are the cause of a functional deficit in the VNC or an effect of it. A better understanding of the neurochemical changes that occur during aging may be important for the development of potential drug treatments for age-related vestibular disorders. However, this will require the use of more sophisticated methodology such as in vivo microdialysis with single neuron recording and perhaps new technologies such as optogenetics. PMID:26973593

  15. Age-Related Neurochemical Changes in the Vestibular Nuclei

    Directory of Open Access Journals (Sweden)

    Paul eSmith

    2016-03-01

    Full Text Available There is evidence that the normal aging process is associated with impaired vestibulo-ocular (VOR and vestibulo-spinal reflexes, causing reduced visual acuity and postural instability. Nonetheless, the available evidence is not entirely consistent, especially with respect to the VOR. Some recent studies have reported that VOR gain can be intact even above 80 years of age. Similarly, although there is evidence for age-related hair cell loss and neuronal loss in Scarpa’s ganglion and the vestibular nucleus complex (VNC, it is not entirely consistent. Whatever structural and functional changes occur in the VNC as a result of aging, either to cause vestibular impairment or to compensate for it, neurochemical changes must underlie them. However, the neurochemical changes that occur in the VNC with aging are poorly understood because the available literature is very limited. This review summarises and critically evaluates the available evidence relating to the noradrenaline, serotonin, dopamine, glutamate, GABA, glycine, and nitric oxide neurotransmitter systems in the aging VNC. It is concluded that, at present, it is difficult, if not impossible, to relate the neurochemical changes observed to the function of specific VNC neurons and whether the observed changes are the cause of a functional deficit in the VNC or an effect of it. A better understanding of the neurochemical changes that occur during aging may be important for the development of potential drug treatments for age-related vestibular disorders. However, this will require the use of more sophisticated methodology such as in vivo microdialysis with single neuron recording and perhaps new technologies such as optogenetics.

  16. In vivo observation of age-related structural changes of dermal collagen in human facial skin using collagen-sensitive second harmonic generation microscope equipped with 1250-nm mode-locked Cr:Forsterite laser

    Science.gov (United States)

    Yasui, Takeshi; Yonetsu, Makoto; Tanaka, Ryosuke; Tanaka, Yuji; Fukushima, Shu-ichiro; Yamashita, Toyonobu; Ogura, Yuki; Hirao, Tetsuji; Murota, Hiroyuki; Araki, Tsutomu

    2013-03-01

    In vivo visualization of human skin aging is demonstrated using a Cr:Forsterite (Cr:F) laser-based, collagen-sensitive second harmonic generation (SHG) microscope. The deep penetration into human skin, as well as the specific sensitivity to collagen molecules, achieved by this microscope enables us to clearly visualize age-related structural changes of collagen fiber in the reticular dermis. Here we investigated intrinsic aging and/or photoaging in the male facial skin. Young subjects show dense distributions of thin collagen fibers, whereas elderly subjects show coarse distributions of thick collagen fibers. Furthermore, a comparison of SHG images between young and elderly subjects with and without a recent life history of excessive sun exposure show that a combination of photoaging with intrinsic aging significantly accelerates skin aging. We also perform image analysis based on two-dimensional Fourier transformation of the SHG images and extracted an aging parameter for human skin. The in vivo collagen-sensitive SHG microscope will be a powerful tool in fields such as cosmeceutical sciences and anti-aging dermatology.

  17. 中国人口年龄结构变动对出生率的影响研究%Study the Effect of Population Age Structure Changes on the Crude Birth Rate in China

    Institute of Scientific and Technical Information of China (English)

    袁小平; 梁海艳

    2014-01-01

    本文利用相关年份的《中国统计年鉴》和人口普查数据,根据粗出生率与总和生育率的关系与特征,构建了人口年龄结构系数及其对粗出生率变动影响的贡献率指标,分析了建国以来人口年龄结构变动对出生率的影响。研究发现:1949—1979年,人口年龄结构变动对出生率的影响很小;1980—1993年,人口年龄结构变动对出生率的影响迅速上升,年龄结构的贡献率增大;1994—2008年,人口年龄结构变动对出生率的影响趋于下降,人口惯性势能在减弱;2009—2011年,受80—90年代出生高峰的影响,人口年龄结构变动对出生率的影响再次凸显,年龄结构的贡献率迅速增大。从年龄别生育率逐年下降的特点,也可以证明近年推动我国人口增长的力量主要是由于年龄结构带来的惯性增长。%s:This paper take uses of China Statistical Yearbook and census data. According to the relationships and characteris-tics of the crude birth rate and total fertility rate ,put up with the indicator of population age structure coefficient and its con-tribution share to the influence on the crude birth rate changes. And then analysis the impact of changes population age struc-ture on the birth rate since the founding of new China. Research found:1949-1979,population age structure changes impact to the birth rate was slightly;1980-1993,population age structure changes impact to the birth rate quickly rose ,contribution share increased much;1994-2008,population age structure changes impact to the crude birth rate tends to declined , popula-tion inertia potential energy in weakened;2009-2011,for the 80-90 birth cohort peak, population age structure changes im-pact to the crude birth rate again highlights. The population age structure ’s contribution share increases quickly. From the characteristics of the age-specific fertility rate has been declining , also could prove that in recent

  18. An update on the Structural Aging Program

    International Nuclear Information System (INIS)

    The Structural Aging (SAG) Program is being conducted at the Oak Ridge National Laboratory (ORNL) for the Nuclear Regulatory Commission (NRC). The SAG Program is addressing the aging management of safety-related concrete structures in nuclear power plants for the purpose of providing improved technical bases for their continued service. The program is organized into four tasks: Program Management, Materials Property Data Base, Structural Component Assessment/Repair Technologies, and Quantitative Methodology for Continued Service Determinations. Objectives and a summary of accomplishments under each of these tasks are presented

  19. Smoking and cognitive change from age 11 to age 80

    OpenAIRE

    Deary, Ian J; Pattie, Alison; M. D. Taylor; Whiteman, Martha C; Starr, John M; Lawrence J Whalley

    2003-01-01

    Age related cognitive decline affects people’s quality of life and their ability to live independently. A recent review stated, "[we] are aware of no studies on the relationship between smoking and cognitive decline associated with normal aging or studies of the effect of smoking on cognition in normally aging individuals." Some previous studies examined smoking in relation to pathological cognitive aging, but lacked cognitive data before the initiation of smoking, and used crude clinical cog...

  20. Changing Attitudes towards Ageing and the Aged amongst Psychology Students

    Science.gov (United States)

    Fonseca, Antonio; Goncalves, Daniela; Martin, Ignacio

    2009-01-01

    Society is ageing. In Europe, the ageing of the population is a recurrent and discussed theme. The impact of the ageing of the population is varied and transversal in different fields. The increase in the number of elderly people implies an increase in the levels of dependence and, consequently, more sanitary, physical, and human resources. Also,…

  1. Changing Market Relationships in the Internet Age

    OpenAIRE

    Lambin, Jean-Jacques

    2013-01-01

    This volume, which takes the form of an essay, attempts to structure a forward- looking approach to the evolving role of marketing in today’s economy. Many organisations today recognize the need to become more market responsive in view of the growing complexity of the global and interconnected market in which they operate. Internet technology is resulting in an increasingly globalised market, with easier access to information, new market players and new forms of partnerships. It is also chang...

  2. Aging and Cancer Mortality: Dynamics of Change and Sex Differences

    OpenAIRE

    Yang, Yang; Li, Ting; Nielsen, Matthew E.

    2012-01-01

    Age-related changes in cancer mortality risk are important for understanding the processes of disease and aging interaction. The extent to which these age changes differ by sex further contributes to this understanding but has not been well studied to date. We conducted a systematic examination of dynamics and heterogeneity of age changes in cancer mortality rates for the top 14 cancer sites using vital statistics from the NCHS and SEER between 1969 and 2007. We assessed patterns of age chang...

  3. [Changes of marriage age in ancient China].

    Science.gov (United States)

    Zhang, D

    1991-04-01

    The changes in age of marriage in ancient China can be classified into 3 periods. Around 680 B.C., the government set the age of marriage at 20 for men and at 15 for women. Even though it was written in the works of the Confucian school that men should marry at 30 and women at 20, it was never really followed. The Wei and Jin dynasties provided the longest periods of war and social instability. Large numbers of population died because of war or famine. Because heavy taxes were collected on each member of family, many families did not report marriage or childbirth. In order to encourage childbirth, the government reduced the age of marriage to 15 for men and 13 for women. Administrative and legislative regulation were introduced to force people to marry early, especially women. Incentives were given to families with more women. These policies was enforced due to the imbalance of the sex ratio and reduction of population size. As female infanticides were prevalent because of differential values placed on male and female children, it was difficult for men to find partners to marry. Shortage of women was also the result of the polygamy of the rich and the aristocracy. The imbalance of the sex ratio forced women to marry early. Nevertheless, women getting married too early were not fertile. Infant or child mortality was high among children of young mothers. From the Song to the Ching dynasties, the age of marriage was set at 16 for men and 14 for women. In the ancient times, the population of China was around 60-70 million before the Ching dynasty. Generally speaking, the population size was small. Early marriage was necessary and feasible. Even though fertility in ancient times was high, mortality has high also. Life expectancy ranged form 22 to 35. People needed to marry early and have children early to replace themselves. On the other hand, large land areas and inefficient production tools required a larger labor force. Large population size also represented

  4. The changing understanding of ageing. Part 3: Diseases of ageing

    Directory of Open Access Journals (Sweden)

    Dennis F. Lawler

    2011-09-01

    Full Text Available This third and final paper in this series considers ageing mechanisms across species, with emphasis on conserved metabolic pathways that relate to disease. The growth hormone (GH-insulin-like growth factor (IGF-1-insulin axis continues as an example of how critical pathways might relate to longevity and senescence. Aligning theory, research outcomes and clinical investigations at the levels of the cell, organism and population, is suggested as a means by which to consider the many complexities of the ageing process in an orderly fashion. A contentious debate revolves around whether ageing is purely a combined effect of stochastic events on residual programming relating to reproductive robustness, or whether ageing itself is programmed by natural selection. Emerging data indicate that the influence of genetic programming on specific late-life diseases, and even individual tissue pathologies, will probably need to be reconsidered in the light of newer theoretical possibilities. In particular, the evidence that late life and its diseases are objects of considerable investment of energy challenges theory that couples longevity with reproduction. Furthermore, the author suggests that ageing may have evolved at least partly as a means of niche preservation for contemporaries and for progeny.

  5. Age structure of the workforce and firm performance

    DEFF Research Database (Denmark)

    Westergård-Nielsen, Niels Chr.; Grund, Christian

    2008-01-01

    Purpose - Given the ongoing demographic change in European countries, this paper aims to exploreempirically the link between age structures of employees in firms and firm performance. Design/methodology/approach - Based on theoretical considerations, the paper examines the linkbetween both...... structures and firm performance for a whole country. The paper gives insights for both academic scholars and practitioners, who may take the results into account in formulating an efficient personnel policy....

  6. Age changes of the knee menisci

    International Nuclear Information System (INIS)

    This paper reports on MR signal changes in the menisci due to degenerative disease that can be confused with those of a tear. The value of MR imaging in analysis of degenerated menisci was studied. MR imaging followed by careful specimen preparation allowed correlation of gross pathologic findings in 308 3-mm-thick sections in 20 cadaveric knees with T1-weighted, proton density, T2-weighted, and gradient-echo images (multiplanar gradient recalled [MPGR]). The age range of cadavers was 56-88 years (mean, 73.8). A subset of 179 images was read blindly and compared with the corresponding anatomic sections and histologic slides. The accuracy of the combined spin-echo images in the analysis of meniscal degeneration was 80.4%, the sensitivity was 81.4%, and the specificity was 80.1%. The corresponding results for the MPGR images were 68.7%, 87.8%, and 63.0%, respectively. Mucoid degeneration generated signal behavior similar to that described for tears. The more circumscribed nature of the signal and the persistence of the increased signal on T2-weighted images in tears were helpful for differentiation

  7. Progress in research on aging of structures

    International Nuclear Information System (INIS)

    The Structural Aging (SAG) Program is conducted for the Nuclear Regulatory Commission. The program has the overall objective of preparing an expandable handbook or report which will provide the NRC with potential structural safety issues and acceptance criteria for use in nuclear power plant evaluations for continued service. Initial focus of the program is on concrete and concrete-related materials which comprise the safety-related (Category I) structures in light-water reactor facilities. The program consists of a management task and three technical tasks: materials property data base, structural component assessment/repair technology, and quantitative methodology for continued service determinations. Objectives, background information, and accomplishments under each of these tasks are presented

  8. Analysis on age structure of Zoysia japonica(Poaceae) population

    Institute of Scientific and Technical Information of China (English)

    WANGYan; DAIBao-qing; LIANGYong-jun; MALian-ju

    2003-01-01

    The age-structure of natural population of Zoysia japonica in Xiuyan County of Liaoning Province was studied by generational method.The results showed that the highest tiller age class was three,but 1st age class tillers held dominant position with proportions over 95% in each month during the growing seasons.The 2nd age class and 2rd age class tillers were minority in the population.So Z.japonica population was an expanding population.The zero age class buds on the rhizomes were dominantin buds age structures.The proportion of buds to tillers on quantity in each month was about 30% to 40% and reached the highest at the end of September.The increasing of buds proportion before dormancy guaranteed the quantity of tillers in the next spring.The biomass of 1st age class tillers changed with time.The biomass kept increasing from April to July and reached the highest at the end of July and then decreased.

  9. Age-Related Changes in the Misinformation Effect.

    Science.gov (United States)

    Sutherland, Rachel; Hayne, Harlene

    2001-01-01

    Two experiments examined relation between age-related changes in retention and age-related changes in the misinformation effect. Found large age-related retention differences when participants were interviewed immediately and after 1 day, but after 6 weeks, differences were minimal. Exposure to misleading information increased commission errors.…

  10. 8 Areas of Age-Related Change

    Science.gov (United States)

    ... effectiveness and safety of three minimally invasive surgical therapies to treat benign prostate enlargement, which is common in men as they age. 6. Dental: gingivitis, periodontitis, loss of teeth Tooth decay is not ...

  11. 8 Areas of Age-Related Change

    Science.gov (United States)

    ... age. 6. Dental: gingivitis, periodontitis, loss of teeth Tooth decay is not just a problem for children. It ... as you have natural teeth in your mouth. Tooth decay ruins the enamel that covers and protects your ...

  12. Aging changes in the bones - muscles - joints

    Science.gov (United States)

    ... of the vertebrae can cause pain and reduce mobility. Muscle weakness contributes to fatigue, weakness, and reduced ... changes in the nerves. Decreased knee jerk or ankle jerk can occur. Some changes, such as a ...

  13. Changes of the ash structure

    Science.gov (United States)

    Peer, Václav; Friedel, Pavel; Janša, Jan

    2016-06-01

    The aim of the article is to appraisal of the changes in the structure of the ash due to the addition of compounds capable of the eutectics composition change. For the transformation were used limestone and dolomite dosed in amounts of 2, 5 and 10 wt.% with pellets of spruce wood, willow wood and refused derived fuel. Combustion temperatures of the mixtures were adjusted according to the temperatures reached during the using of fuels in power plants, i.e. 900, 1000, 1100 and 1200 °C.

  14. Radical Change Revisited: Dynamic Digital Age Books for Youth

    Science.gov (United States)

    Dresang, Eliza T.

    2008-01-01

    Radical change, a theory described in Eliza Dresang's 1999 book, "Radical Change: Books for Youth in a Digital Age," was developed in the mid-1990s. It serves as a lens through which to examine, explain, and ultimately, use contemporary literature for youth growing up in the Digital Age. It identifies changes in forms and formats,…

  15. Population Aging and the Direction of Technical Change

    OpenAIRE

    Irmen, Andreas

    2009-01-01

    An analytical framework is developed to study the repercussions between endogenous capital- and labor-saving technical change and population aging. Following an intuition often attributed to Hicks (1932), I ask whether and how population aging aff ects the relative scarcity of factors of production, relative factor prices, and the direction of induced technical change. Aging is equivalent to an increase in the old-age dependency ratio of an OLG-economy with two-period lived individuals. In th...

  16. Growth, Employment and Structural Change

    DEFF Research Database (Denmark)

    Aggarwal, Aradhna

    2016-01-01

    This paper studies the decomposition of GSDP growth per capita in Punjab via-a-vis 15 other states in India during 1993–94 and 2011–12 in terms of employment and productivity growth. Specifically, it focuses on the role of employment growth and structural change in employment on economic growth....... It reviews the theoretical rationale, presents the growth patterns in GSDP and employment, and estimates the employment-productivity components of GSDP growth per capita using the Shapley decomposition analysis. The results show that Punjab has slipped in terms of GSDP per capita over this period...... to be positive. Finally, while the state was outpaced by other states in terms of growth rate in GSDP per capita and even employment, structural change in the economy has been a positive feature of growth in the state....

  17. Status Maintenance and Change during Old Age.

    Science.gov (United States)

    Pampel, Fred C.; Hardy, Melissa

    1994-01-01

    Uses national longitudinal survey data to compare the impact of status characteristics important during work careers (race, residence, education, occupation) on men's economic outcomes before and after the normal age of eligibility for retirement benefits. Results generally (but not completely) support the argument that determinants of income…

  18. THE STRUCTURE ANALYSIS OF POPULATION BY AGE GROUPS IN THE RURAL AREAS OF BUCOVINA

    Directory of Open Access Journals (Sweden)

    NICOLETA ILEANA MORAR (BUMBU

    2015-12-01

    Full Text Available The structure analysis of population by age groups in the rural area of Bucovina desires to create a recent image of the rural population by age groups in the region of Bucovina , provided that after the year 2000 have occurred socio – economic changes with repercussions on the demographic component. The structure analysis by age group will be based on the share of population indicators on the major age groups, the share of population by age and quinquennial gender illustrated by age pyramid, the index of demographic aging and age-dependency ratio. This study is definitely needed in forecasting future regional development objectives and measures.

  19. Empiricism, Structuralism and Scientific Change

    Directory of Open Access Journals (Sweden)

    Susana Lucero

    2008-06-01

    Full Text Available In the last decades there was a structural turn in the classic debate between scientific realists and antirealists with empiricist orientation. Two main arguments support the realist conception: the ‘No Miracle Argument’ and the thesis of continuity. The thesis of continuity states that some parts of a theory are retained when a scientific change takes place. In a current famous article, J. Worrall (1989 defends the continuity argument by stating that what is preserved in the succession of two empirically successful theories are the relations among the postulated entities and not the nature of the relata (structural or syntactical realism. Based on this perspective, van Fraassen introduces his position named Empiricist Structuralism, which claims that only the structures of phenomena are retained. This conception tries to explain the success of science and at the same time defend the continuity of structures. I will demonstrate in this paper that the accomplishment of the two mentioned requirements imply a capitulation in favor of realistic intuitions.

  20. Adaptive evolvement of information age C4ISR structure

    Institute of Scientific and Technical Information of China (English)

    Yushi Lan; Kebo Deng; Shaojie Mao; Heng Wang; Kan Yi; Ming Lei

    2015-01-01

    Command, control, communication, computing, intel-ligence, surveil ance and reconnaissance (C4ISR) in information age is a complex system whose structure always changes ac-tively or passively during the warfare. Therefore, it is important to optimize the structure, especial y in ambiguous and quick-tempo modern warfare. This paper proposes an adaptive evolvement mechanism for the C4ISR structure to survive the changeable warfare. Firstly, the information age C4ISR structure is defined and modeled based on the complex network theory. Secondly, taking the observe, orient, decide and act (OODA) model into consideration, four kinds of loops in the C4ISR structure are pro-posed and their coefficient of networked effects (CNE) is further defined. Then, the adaptive evolvement mechanisms of the four kinds of loops are presented respectively. Final y, taking the joint air-defense C4ISR as an example, simulation experiments are im-plemented, which validate the evolvement mechanism and show that the information age C4ISR structure has some characteristics of smal-world network and scale-free network.

  1. Changes in access to structural social capital and its influence on self-rated health over time for middle-aged men and women: a longitudinal study from northern Sweden.

    Science.gov (United States)

    Eriksson, Malin; Ng, Nawi

    2015-04-01

    Until recently, most studies on social capital and health have been cross-sectional making it difficult to draw causal conclusions. This longitudinal study used data from 33,621 individuals (15,822 men and 17,799 women) from the Västerbotten Intervention Program, to analyse how changes in access to individual social capital influence self-rated health (SRH) over time. Two forms of structural social capital, i.e. informal socializing and social participation, were measured. Age, sex, education, marital status, smoking, snuff, physical activity, alcohol consumption, high blood pressure, and body mass index were analysed as potential confounders. The association between changes in access to structural social capital and SRH in the follow-up was adjusted for SRH at baseline, as well as for changes in the socio-demographic and health-risk variables over time. The results support that changes in access to structural social capital over time impact on SRH. Remaining with no/low level of informal socializing over time increased the odds ratio for poor SRH for both men and women (OR of 1.45; 95%CI = 1.22-1.73 among men and OR of 1.56; 95%CI = 1.33-1.84 among women). Remaining with no/low levels of social participation was also detrimental to SRH in men and women (OR 1.14; 95%CI = 1.03-1.26 among men and OR 1.18; 95%CI = 1.08-1.29 among women). A decrease in informal socializing over time was associated with poor SRH for women and men (OR of 1.35; 95%CI = 1.16-1.58 among men and OR of 1.57; 95%CI = 1.36-1.82 among women). A loss of social participation had a negative effect on SRH among men and women (OR of 1.16; 95%CI = 1.03-1.30 among men and OR of 1.15; 95%CI = 1.04-1.27 among women). Gaining access to social participation was harmful for SRH for women (OR 1.17; 95%CI = 1.05-1.31). Structural social capital has complex and gendered effects on SRH and interventions aiming to use social capital for health promotion purposes require an awareness of its gendered nature.

  2. NHS System Reform: Structural Changes

    Directory of Open Access Journals (Sweden)

    H Ravaghi

    2005-10-01

    Full Text Available The National Health Service (NHS was established in 1948 to provide equitable healthcare for all citizens. Over the years the NHS has gone under different reforms and changes. In 2002 the NHS launched one of its biggest changes in structure since its commencement in 1948. The scale of these changes are greater than those established following the white paper “Working for Patients” in 1989 (Conservative Government that indicated the introduction of the internal market (focus on efficiency. This review therefore proposes to give a brief summarize of the structural changes and current structure of the NHS in the England. The NHS plan was published in July 2000 (Labour Government and outlined a 10 year plan of investment in the NHS. This delineates a vision for a service planned around the patients and more responsive to patients’ needs. The Government emphasizes on the empowering of staff at all levels as a way to achieve this vision. "Shifting the Balance of Power" is part of the Government’s plans for implementation of the NHS Plan and has directed to the establishment of new structures. The main feature of change has been giving locally based Primary Care Trusts the role of running the NHS and, with the local authorities, improving health in their areas. The PCTs are receiving 75% of the NHS budget to act as primary services provider, commissioner (service purchaser, network developer and controller. In addition, all former Health Authorities have been abolished and new Strategic Health Authorities (SHA have been created to serve larger areas and with a more strategic role. The SHAs are responsible for developing strategic frameworks for the local health service; performance of the local health service; and building capacity in the local health service. The Department of Health is also refocusing to reflect these changes, including the abolition of its Regional Offices and relegating some of its operational responsibilities to SHAs and

  3. Normal age-related brain morphometric changes: Nonuniformity across cortical thickness, surface area and grey matter volume?

    OpenAIRE

    Lemaitre, H; Goldman, AL; Sambataro, F; Verchinski, BA; Meyer-Lindenberg, A; Weinberger, DR; Mattay, VS

    2010-01-01

    Normal aging is accompanied by global as well as regional structural changes. While these age-related changes in grey matter volume have been extensively studied, less has been done using newer morphological indices such as cortical thickness and surface area. To this end, we analyzed structural images of 216 healthy volunteers, ranging from 18 to 87 years of age, using a surface-based automated parcellation approach. Linear regressions of age revealed a concomitant global age-related reducti...

  4. CHANGES IN NEUROTRANSMITTER GENE EXPRESSION IN THE AGING RETINA.

    Science.gov (United States)

    To understand mechanisms of neurotoxicity in susceptible populations, we examined age-related changes in constitutive gene expression in the retinas of young (4mos), middle-aged (11 mos) and aged (23 mos) male Long Evans rats. Derived from a pouch of the forebrain during develop...

  5. Age-related changes in murine T cell function

    NARCIS (Netherlands)

    C.S. Vissinga (Christine)

    1988-01-01

    textabstractThe aim of the studies presented here was to obtain a more detailed and integrated picture of the age-related changes in cellular immunity. The age-related changes of cellular immunity were studied by in vivo induction of DTH responses to a variety of antigens (Chapters 2 and 3). The res

  6. Radical Change: Digital Age Literature and Learning.

    Science.gov (United States)

    Dresang, Eliza T.; McClelland, Kathryn

    1999-01-01

    Describes the concept of radical change, a theoretical construct that identifies and explains books with characteristics reflecting the types of interactivity, connectivity, and access that permeate the emerging digital society. Highlights innovative ways that authors, illustrators, and designers incorporate these features into books for…

  7. Ultrasonographic assessment of skin structure according to age

    Directory of Open Access Journals (Sweden)

    Diana Crisan

    2012-01-01

    Full Text Available Background: High-frequency ultrasound is a noninvasive tool that offers characteristic markers, quantifying the cutaneous changes of the physiological senescence process. Aims: The aim was to assess the changes in skin thickness, dermal density and echogenicity, as part of the ageing process, with different age intervals. Methods : The study was performed on 160 patients, aged 40.4 ± 21.2, divided into four age categories: <20, 21-40, 41-60, 61-80. Ultrasonographic images (Dermascan device were taken from three sites: dorsal forearm (DF, medial arm (MA, zygomatic area (ZA. We assessed the thickness of epidermis and dermis (mm, number of low, medium, high echogenicity pixels, the ratio between the echogenicity of the upper and lower dermis (LEPs/LEPi, and SLEB (subepidermal low echogenicity band. The statistical analysis was performed using SPSS 15.00. A P value <0.05 was considered significant. Results: On all examined sites, it was found that the dermal thickness increases in the 21 to 40 year interval (P<0.0001. After the 21 to 40 year interval, the number of low echogenic pixels increases significantly, especially on photoexposed sites. High-echogenic pixels follow the same pattern on all examined sites: they increase in the 21 to 40 year interval and decrease in the 3rd and 4th age category. The LEPs/LEPi ratio increases significantly with age, at all sites (P<0.05, due to an increase of hypoechogenic pixels in the upper dermis. Conclusions: High-frequency ultrasound is a noninvasive "histological" tool that can assess the cutaneous structure and age-related changes. It offers imagistic markers, comparable to the histological parameters and also characteristic ultrasonographic markers. Histology remains the gold standard for the investigation of the integumentary system.

  8. Ageing: Cognitive change and the APOEe4 allele

    OpenAIRE

    Deary, Ian J; Whiteman, Martha C; Pattie, Alison; Starr, John M; Hayward, Caroline; Wright, Alan F.; Carothers, Andrew; Lawrence J Whalley

    2002-01-01

    There is a marked variation in whether people retain sufficient cognitive function to maintain their quality of life and independence in old age, even among those without dementia, so it would be valuable to identify the determinants of normal age-related cognitive change (1,2). We have retested non-demented 80-year-olds who were participants in the Scottish Mental Survey of 1932, and find that the variation in their non-pathological cognitive change from age ...

  9. [Esophageal wall structure in people of elderly and senile age].

    Science.gov (United States)

    aminova, G G; Grigorenko, D E; Sapin, M R; Mkhitarov, V A

    2014-01-01

    Using histological methods, the esophageal wall structure and the cytoarchitectonics of mucous membrane were studied in the individuals of elderly (n = 5) and senile (n = 10) age. The control group included the individuals of I (n = 3) and II (n = 3) periods of mature age. It was demonstrated that with advancing age in most cases the destructive processes took place in the epithelium (delamination of the layer, separation of large fragments, formation of microerosions etc.) in most of the studied cases. Lymphocytes, neutrophils and eosinophils were found between the epithelial cells; the numbers of infiltrating cells was increased 2-3 times during aging. Mucosal lamina propria and the submucosa, in particular, were characterized by the thickening of the bundles of collagen fibers. A two-fold increase in the number of the cells of the fibroblast lineage was found. The number of leukocytes in the lamina propria was increased by the eldery age in the upper and lower parts of the esophagus (3.5 and 1.75 times respectively). The changes in lamina muscularis were manifested by its thinning, delamination and myocyte dissociation. Remodeling of the muscular tunic was less pronounced. The degree of changes increased distally and varied widely depending on the individual peculiarities. PMID:25282822

  10. Aging induced changes on NEXAFS fingerprints in individual combustion particles

    Directory of Open Access Journals (Sweden)

    V. Zelenay

    2011-11-01

    Full Text Available Soot particles can significantly influence the Earth's climate by absorbing and scattering solar radiation as well as by acting as cloud condensation nuclei. However, despite their environmental (as well as economic and political importance, the way these properties are affected by atmospheric processing of the combustion exhaust gases is still a subject of discussion. In this work, individual soot particles emitted from two different vehicles, a EURO 2 transporter, a EURO 3 passenger car, and a wood stove were investigated on a single-particle basis. The emitted exhaust, including the particulate and the gas phase, was processed in a smog chamber with artificial solar radiation. Single particle specimens of both unprocessed and aged soot were characterized using near edge X-ray absorption fine structure spectroscopy (NEXAFS and scanning electron microscopy. Comparison of NEXAFS spectra from the unprocessed particles and those resulting from exhaust photooxidation in the chamber revealed changes in the carbon functional group content. For the wood stove emissions, these changes were minor, related to the relatively mild oxidation conditions. For the EURO 2 transporter emissions, the most apparent change was that of carboxylic carbon from oxidized organic compounds condensing on the primary soot particles. For the EURO 3 car emissions oxidation of primary soot particles upon photochemical aging has likely contributed as well. Overall, the changes in the NEXAFS fingerprints were in qualitative agreement with data from an aerosol mass spectrometer. Furthermore, by taking full advantage of our in situ microreactor concept, we show that the soot particles from all three combustion sources changed their ability to take up water under humid conditions upon photochemical aging of the exhaust. Due to the selectivity and sensitivity of the NEXAFS technique for the water mass, also small amounts of water taken up into the internal voids of agglomerated

  11. The Nanometer Age: Challenge and Change

    Science.gov (United States)

    Rohrer, Heinrich

    [This address was presented by Heinrich Rohrer as the Nishina Memorial Lecture at the University of Tokyo, on June 25, 1993.] The newplayers in the emerging nano-world are individual, selected objects of the size of some 50 nm down to molecules and atoms. The new aspect of science and technology on the nanometer scale is that these objects are treated as individuals, not as ensemble members. To a great extent, this requires real-space methods. Local probe methods, such as scanning tunneling microscopy and its derivatives, are therefore a key to the nanoworld. Major challenges of the new nanometer world are to exploit the new possibilities that arise from nanometer dimensions, to interface the macroscopic world to nano-individuals, to establish new concepts for working with very large numbers of nano-individuals and large sets of control parameters, to create the basis for broad interdisciplinarity, and to prepare society for the tremendous changes anticipated in a nanometer world.

  12. Age-related cerebral white matter changes on computed tomography

    International Nuclear Information System (INIS)

    Changes of cerebral white matter on computed cranial tomography related to aging were studied in 70 subjects aged 30 to 94 years. The subjects had no histories of cerebrovascular accidents and no abnormalities in the central nervous system were shown by physical examinations and CT scans. We measured the average attenuation values (CT numbers) of each elliptical region (165 pixels, 0.39cm2) in the bilateral thalamus and twelve areas of deep white matter. Multiple regression analysis was used to assess the effects of age, cranial size and cranial bone CT numbers on the brain CT numbers. We also studied the association between brain CT numbers and brain atrophy, hypertension, diabetes mellitus. CT numbers of frontal white matter surrounding anterior horns decreased with aging in 70 subjects aged 30 to 94 years. No significant correlation between age and brain CT numbers was found in any other region by multivariate analysis, because of the prominent effect of cranial bone CT numbers on brain CT numbers. Although no age-related changes of white matter CT numbers was found in 41 subjects aged 30 to 65 years, there were significant negative correlations between age and white matter CT numbers at all regions in 29 subjects aged 66 to 94 years. Brain atrophy was associated with brain CT numbers. No association was found for hypertension or diabetes mellitus. Brain CT numbers decreased with aging even in neurologically healthy persons in older age. Brain CT numbers also decreased as cerebral atrophy advanced. (author)

  13. Age-related cerebral white matter changes on computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, Hitoshi; Kobayashi, Shotai; Koide, Hiromi; Yamaguchi, Shuhei; Okada, Kazunori; Shimote, Kouichi; Tsunematsu, Tokugoro

    1989-01-01

    Changes of cerebral white matter on computed cranial tomography related to aging were studied in 70 subjects aged 30 to 94 years. The subjects had no histories of cerebrovascular accidents and no abnormalities in the central nervous system were shown by physical examinations and CT scans. We measured the average attenuation values (CT numbers) of each elliptical region (165 pixels, 0.39cm/sup 2/) in the bilateral thalamus and twelve areas of deep white matter. Multiple regression analysis was used to assess the effects of age, cranial size and cranial bone CT numbers on the brain CT numbers. We also studied the association between brain CT numbers and brain atrophy, hypertension, diabetes mellitus. CT numbers of frontal white matter surrounding anterior horns decreased with aging in 70 subjects aged 30 to 94 years. No significant correlation between age and brain CT numbers was found in any other region by multivariate analysis, because of the prominent effect of cranial bone CT numbers on brain CT numbers. Although no age-related changes of white matter CT numbers was found in 41 subjects aged 30 to 65 years, there were significant negative correlations between age and white matter CT numbers at all regions in 29 subjects aged 66 to 94 years. Brain atrophy was associated with brain CT numbers. No association was found for hypertension or diabetes mellitus. Brain CT numbers decreased with aging even in neurologically healthy persons in older age. Brain CT numbers also decreased as cerebral atrophy advanced. (author).

  14. The Digital Ageing Atlas: integrating the diversity of age-related changes into a unified resource.

    Science.gov (United States)

    Craig, Thomas; Smelick, Chris; Tacutu, Robi; Wuttke, Daniel; Wood, Shona H; Stanley, Henry; Janssens, Georges; Savitskaya, Ekaterina; Moskalev, Alexey; Arking, Robert; de Magalhães, João Pedro

    2015-01-01

    Multiple studies characterizing the human ageing phenotype have been conducted for decades. However, there is no centralized resource in which data on multiple age-related changes are collated. Currently, researchers must consult several sources, including primary publications, in order to obtain age-related data at various levels. To address this and facilitate integrative, system-level studies of ageing we developed the Digital Ageing Atlas (DAA). The DAA is a one-stop collection of human age-related data covering different biological levels (molecular, cellular, physiological, psychological and pathological) that is freely available online (http://ageing-map.org/). Each of the >3000 age-related changes is associated with a specific tissue and has its own page displaying a variety of information, including at least one reference. Age-related changes can also be linked to each other in hierarchical trees to represent different types of relationships. In addition, we developed an intuitive and user-friendly interface that allows searching, browsing and retrieving information in an integrated and interactive fashion. Overall, the DAA offers a new approach to systemizing ageing resources, providing a manually-curated and readily accessible source of age-related changes.

  15. Effects of Age on Time-Dependent Cognitive Change

    OpenAIRE

    Salthouse, Timothy A.

    2011-01-01

    Interpretation of cognitive change has been complicated because different influences on change are not easily distinguished. In this study, longitudinal cognitive change was decomposed into a component related to the length of the interval between test occasions (i.e., time-dependent change) and a component unrelated to the test-retest interval (i.e., time-independent change). Influences of age on the two hypothesized components were investigated in a sample of more than 1,500 adults for whom...

  16. Crystal structure of patatin-17 in complex with aged and non-aged organophosphorus compounds.

    Directory of Open Access Journals (Sweden)

    Sanjeeva J Wijeyesakere

    Full Text Available Patatin is a non-specific plant lipase and the eponymous member of a broad class of serine hydrolases termed the patatin-like phospholipase domain containing proteins (PNPLAs. Certain PNPLA family members can be inhibited by organophosphorus (OP compounds. Currently, no structural data are available on the modes of interaction between the PNPLAs and OP compounds or their native substrates. To this end, we present the crystal structure of patatin-17 (pat17 in its native state as well as following inhibition with methyl arachidonyl fluorophosphonate (MAFP and inhibition/aging with diisopropylphosphorofluoridate (DFP. The native pat17 structure revealed the existence of two portals (portal1 and portal2 that lead to its active-site chamber. The DFP-inhibited enzyme underwent the aging process with the negatively charged phosphoryl oxygen, resulting from the loss of an isopropyl group, being within hydrogen-binding distance to the oxyanion hole. The MAFP-inhibited pat17 structure showed that MAFP did not age following its interaction with the nucleophilic serine residue (Ser77 of pat17 since its O-methyl group was intact. The MAFP moiety is oriented with its phosphoryl oxygen in close proximity to the oxyanion hole of pat17 and its O-methyl group located farther away from the oxyanion hole of pat17 relative to the DFP-bound state. The orientation of the alkoxy oxygens within the two OP compounds suggests a role for the oxyanion hole in stabilizing the emerging negative charge on the oxygen during the aging reaction. The arachidonic acid side chain of MAFP could be contained within portals 1 or 2. Comparisons of pat17 in the native, inhibited, and aged states showed no significant global conformational changes with respect to their Cα backbones, consistent with observations from other α/β hydrolases such as group VIIA phospholipase A2.

  17. Dosimetric implications of age related glandular changes in screening mammography

    Science.gov (United States)

    Beckett, J. R.; Kotre, C. J.

    2000-03-01

    The UK National Health Service Breast Screening Programme is currently organized to routinely screen women between the ages of 50 and 64, with screening for older women available on request. The lower end of this age range closely matches the median age for the menopause (51 years), during which significant changes in the composition of the breast are known to occur. In order to quantify the dosimetric effect of these changes, radiographic factors and compressed breast thickness data for a cohort of 1258 women aged between 35 and 79 undergoing breast screening mammography have been used to derive estimates of breast glandularity and mean glandular dose (MGD), and examine their variation with age. The variation of mean radiographic exposure factors with age is also investigated. The presence of a significant number of age trial women within the cohort allowed an extended age range to be studied. Estimates of MGD including corrections for breast glandularity based on compressed breast thickness only, compressed breast thickness and age and for each individual woman are compared with the MGD based on the conventional assumption of a 50:50 adipose/glandular composition. It has been found that the use of the conventional 50:50 assumption leads to overestimates of MGD of up to 13% over the age range considered. By using compressed breast thickness to estimate breast glandularity, this error range can be reduced to 8%, whilst age and compressed breast thickness based glandularity estimates result in an error range of 1%.

  18. Stability and change in intelligence from age 12 to age 52: results from the Luxembourg MAGRIP study.

    Science.gov (United States)

    Schalke, Daniela; Brunner, Martin; Geiser, Christian; Preckel, Franzis; Keller, Ulrich; Spengler, Marion; Martin, Romain

    2013-08-01

    The present longitudinal study tackled 2 key aspects of the development of intelligence across a 40-year time period from age 12 to age 52 concerning (a) stability and change in the structure of intelligence with reference to the age differentiation-dedifferentiation hypothesis (how different cognitive abilities relate to each other across age) and (b) differential stabilities (the rank ordering of persons' intelligence levels across time). To this end, we drew on 2 structural conceptions of intelligence: (a) the extended Gf-Gc model to study broad cognitive abilities and (b) the 3-stratum model to decompose cognitive change into processes that are shared by all broad abilities (attributable to general cognitive ability g) and processes specific to a certain ability (independent of g). Data were obtained for 344 persons (56.4% female). The results showed that people differ more greatly over time with respect to all broad abilities except for fluid reasoning, whereas the rank ordering of persons on all broad abilities remains remarkably stable. These combined results yielded substantial gap-widening effects from age 12 to age 52 years that were mainly accounted for by a substantial increase in g variance in combination with a high differential stability of g. Moreover, the increase in g variance reflects an increase in covariance among different broad abilities, which indicates that the different constructs relate more closely to each other at age 52 compared to age 12 (i.e., age dedifferentiation). Two theoretical explanations of this change in the structure of intelligence are discussed (common cause hypothesis and investment theory). PMID:23148935

  19. MARKET INTEGRATION: CASE STUDIES OF STRUCTURAL CHANGE

    OpenAIRE

    Franken, Jason R.V.; Parcell, Joseph L.

    2003-01-01

    The grain/oilseed industry is undergoing considerable structural change in the form of mergers and the addition of new processing facilities to add value beyond commodity grade. The rapid structural changes in this industry call into question the relevance of previous research conducted in these areas. Focusing on two structural change events in northeast Missouri as case studies provides an incisive glimpse at the larger impact of structural change on the grain/oilseed industry. This study a...

  20. Structure, morphology, and aging of Ag-Fe dumbbell nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Elsukova, Anna; Li, Zi-An; Moeller, Christina; Spasova, Marina; Acet, Mehmet; Farle, Michael [Experimentalphysik (AG Farle) and CENIDE, Universitaet Duisburg-Essen, Duisburg (Germany); Kawasaki, Masahiro [Jeol Inc., Peabody, MA (United States); Ercius, Peter; Duden, Thomas [National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, CA (United States)

    2011-10-15

    Dumbbell-shaped or Janus-type nanocomposites provide multifunctional properties with various diagnostic and therapeutic applications in biomedicine. We have prepared dumbbell Ag-Fe nanoparticles by magnetron sputtering with subsequent in-flight annealing. Structural properties and chemical compositions of freshly prepared and 5-month aged particles were examined by means of transmission electron microscopy including high-resolution imaging, energy dispersive X-ray spectroscopy, and 3D electron tomography. Fresh particles consist of a faceted Ag part on a Fe-Fe{sub 3}O{sub 4} composite particle of more spherical shape. Aging changes the crystallinity and morphology of the particles. The aged nanocomposite consists of a silver spherical particle that is attached to a hollow iron oxide sphere containing one or several silver clusters inside. TEM images of the fresh (a) and aged (b) Ag-Fe nanoparticles. (c) 3D reconstructed image of an aged Ag-Fe particle with color segmentation. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Structural effects of sample ageing in hydrocracked coal liquefaction extracts

    Energy Technology Data Exchange (ETDEWEB)

    Begon, V.; Suelves, I.; Herod, A.A.; Dugwell, D.R.; Kandiyoti, R. [Imperial College, London (United Kingdom). Dept. of Chemical Engineering and Chemical Technology

    2000-10-01

    A sample of Point of Ayr coal extract has been hydrocracked in a microbomb reactor with NiMo on alumina catalyst in tetralin as solvent and hydrogen donor and under hydrogen pressure. The product was separated from solvent and catalyst and then split into equal parts and stored either under nitrogen atmosphere in a freezer or in air at room temperature. Samples of the products were examined at 2 h frequencies for a day, then daily for a week, then at less frequent intervals for a year. Methods used for examination were size exclusion chromatography (SEC) and UV fluorescence spectroscopy (UV-F), both using 1-methyl-2-pyrrolidinone as solvent. Aging was assessed in terms of shifts to shorter elution times in SEC and parallel changes in UV-F spectra. Both stored products showed significant structural evidence of aging over the first week of storage. After that time, changes observed were within the range of variability of the chromatography method based on polystyrene standards. The aging was attributed to the presence of low-reactivity free radicals species, which underwent recombination reactions during storage. These changes are likely to affect the viscosity and combustion characteristics of the hydrocracked product. 30 refs., 6 figs., 1 tab.

  2. Color change of composite resins subjected to accelerated artificial aging

    Directory of Open Access Journals (Sweden)

    Denise Cremonezzi Tornavoi

    2013-01-01

    Conclusions: All composite resins presented unacceptable color changes after 382 h of aging and different composite resins with same hue, presented different colors before being subjected to the aging process (B2 and C2 and after (B2. It was also observed color difference within a group of the same composite resin and same hue.

  3. Radical Change: Books for Youth in a Digital Age

    Science.gov (United States)

    Dresang, Eliza T.

    2008-01-01

    "Radical Change: Books for Youth in a Digital Age" (Dresang, 1999) is a landmark work that examines ways in which young readers are affected by the Digital Age. The impetus for the book grew out of Eliza Dresang's observation that printed books with nonlinear, interactive qualities appeal strongly to contemporary children. She noted that…

  4. Learning and aging related changes in intrinsic neuronal excitability

    Directory of Open Access Journals (Sweden)

    Fernando A Oliveira

    2010-02-01

    Full Text Available A goal of many laboratories that study aging is to find a key cellular change(s that can be manipulated and restored to a young-like state, and thus, reverse the age-related cognitive deficits. We have chosen to focus our efforts on the alteration of intrinsic excitability (as reflected by the postburst afterhyperpolarization, AHP during the learning process in hippocampal pyramidal neurons. We have consistently found that the postburst AHP is significantly reduced in hippocampal pyramidal neurons from young adults that have successfully learned a hippocampus-dependent task. In the context of aging, the baseline intrinsic excitability of hippocampal neurons is decreased and therefore cognitive learning is impaired. In aging animals that are able to learn, neuron changes in excitability similar to those seen in young neurons during learning occur. Our challenge, then, is to understand how and why excitability changes occur in neurons from aging brains and cause age-associated learning impairments. After understanding the changes, we should be able to formulate strategies for reversing them, thus making old neurons function more as they did when they were young. Such a reversal should rescue the age-related cognitive deficits.

  5. Age-Related Changes in Demand-Withdraw Communication Behaviors.

    Science.gov (United States)

    Holley, Sarah R; Haase, Claudia M; Levenson, Robert W

    2013-08-01

    Demand-withdraw communication is a set of conflict-related behaviors in which one partner blames or pressures while the other partner withdraws or avoids. The present study examined age-related changes in these behaviors longitudinally over the course of later life stages. One hundred twenty-seven middle-aged and older long-term married couples were observed at 3 time points across 13 years as they engaged in a conversation about an area of relationship conflict. Husbands' and wives' demand-withdraw behaviors (i.e., blame, pressure, withdrawal, avoidance) were objectively rated by trained coders at each time point. Data were analyzed using dyad-level latent growth curve models in a structural equation modeling framework. For both husbands and wives, the results showed a longitudinal pattern of increasing avoidance behavior over time and stability in all other demand and withdraw behaviors. This study supports the notion that there is an important developmental shift in the way that conflict is handled in later life. PMID:23913982

  6. An investigation of bone mineral density changes with increasing age

    International Nuclear Information System (INIS)

    Purpose: To study bone mineral density changes rule with increasing age for improving reliability of diagnosis of osteoporosis. Method: BMD of forearm, femoral neck and lumbar spine of 313 healthy subjects was measured by dual X-ray absorptiometry using (DXA), Sophos L-XRA. There were 162 males and 151 females (age range 20∼84 years). They were divided into ten year cohorts for analysis. Results: The ages of peak mass of BMD of forearm and lumbar spine were in 30∼39 age-group for both male and female. The peak values of femoral neck, ward's triangle were in 20∼29 age-group of both sexes, BMD declined with increasing age, except the 60∼69 age-group of lumbar spine and femoral neck in male. Conclusion: The lumbar spine measurement with lateral DXA can avoid some adverse influence of post-anterior DXA

  7. Active sensors for health monitoring of aging aerospace structures

    Energy Technology Data Exchange (ETDEWEB)

    GIURGIUTIU,VICTOR; REDMOND,JAMES M.; ROACH,DENNIS P.; RACKOW,KIRK A.

    2000-02-29

    A project to develop non-intrusive active sensors that can be applied on existing aging aerospace structures for monitoring the onset and progress of structural damage (fatigue cracks and corrosion) is presented. The state of the art in active sensors structural health monitoring and damage detection is reviewed. Methods based on (a) elastic wave propagation and (b) electro-mechanical (E/M) impedance technique are cited and briefly discussed. The instrumentation of these specimens with piezoelectric active sensors is illustrated. The main detection strategies (E/M impedance for local area detection and wave propagation for wide area interrogation) are discussed. The signal processing and damage interpretation algorithms are tuned to the specific structural interrogation method used. In the high-frequency E/M impedance approach, pattern recognition methods are used to compare impedance signatures taken at various time intervals and to identify damage presence and progression from the change in these signatures. In the wave propagation approach, the acousto-ultrasonic methods identifying additional reflection generated from the damage site and changes in transmission velocity and phase are used. Both approaches benefit from the use of artificial intelligence neural networks algorithms that can extract damage features based on a learning process. Design and fabrication of a set of structural specimens representative of aging aerospace structures is presented. Three built-up specimens (pristine, with cracks, and with corrosion damage) are used. The specimen instrumentation with active sensors fabricated at the University of South Carolina is illustrated. Preliminary results obtained with the E/M impedance method on pristine and cracked specimens are presented.

  8. Estimating population age structure using otolith morphometrics

    DEFF Research Database (Denmark)

    Doering-Arjes, P.; Cardinale, M.; Mosegaard, Henrik

    2008-01-01

    known-age fish individuals. Here we used known-age Atlantic cod (Gadus morhua) from the Faroe Bank and Faroe Plateau stocks. Cod populations usually show quite large variation in growth rates and otolith shape. We showed that including otolith morphometrics into ageing processes has the potential...... populations. The intercalibration method was successful but generalization from one stock to another remains problematic. The development of an otolith growth model is needed for generalization if an operational method for different populations is required in the future....... to make ageing objective, accurate, and fast. Calibration analysis indicated that a known-age sample from the same population and environment is needed to obtain robust calibration; using a sample from a different stock more than doubles the error rate, even in the case of genetically highly related...

  9. A longitudinal study of brain volume changes in normal aging

    International Nuclear Information System (INIS)

    Purpose: To evaluate the effect of normal aging on brain volumes and examine the effects of age and sex on the rates of changes in global and regional brain volumes. Methods: A total of 199 normal subjects (65 females and 134 males, mean age = 56.4 ± 9.9 years, age range = 38.1–82.9 years) were included in this study. Each subject was scanned twice, at an interval of about 2 years (range = 1.5–2.3 years). Two-time-point percentage brain volume change (PBVC) was estimated with SIENA 2.6. Results: The mean annualized PBVC was −0.23%/y. Analysis of covariance (ANCOVA) for annual brain volume changes revealed a main effect of age. There was no main effect of sex, nor was there a sex-by-age interaction. Voxel-wise analysis revealed a negative correlation between age and edge displacement values mainly in the periventricular region. Conclusions: The results of our study indicate that brain atrophy accelerates with increasing age and that there is no gender difference in the rate of brain atrophy

  10. Ultrasonographic assessment of skin structure according to age

    OpenAIRE

    Diana Crisan; Monica Lupsor; Andreea Boca; Maria Crisan; Radu Badea

    2012-01-01

    Background: High-frequency ultrasound is a noninvasive tool that offers characteristic markers, quantifying the cutaneous changes of the physiological senescence process. Aims: The aim was to assess the changes in skin thickness, dermal density and echogenicity, as part of the ageing process, with different age intervals. Methods : The study was performed on 160 patients, aged 40.4 ± 21.2, divided into four age categories:

  11. The changes of cerebral morphology related to aging in Taiwanese population.

    Directory of Open Access Journals (Sweden)

    Hsiao-Lan Sharon Wang

    Full Text Available A cross-sectional study with the 3-dimensional (3D MRI reconstruction technique was conducted to investigate cerebral complexity changes related to age differences in native Taiwanese population. In our sample of 85 participants aged between 25 and 81, age was associated with gradual ventricular expansion. A nonlinear quadratic relationship between white matter volume and age was found overall in the brain. Widespread age-related reduction in white matter was detected from late adulthood onwards. However, no significant age-related changes in the cortex and whole brain volume were determined throughout adulthood. These findings provided information in describing brain structural complexity, which might in the future serve as an objective diagnostic index or as a predictive parameter for neurological diseases. Our method then may be used for cross-cultural longitudinal studies to evaluate the effect of disease, environment and aging on the brain.

  12. Population structure age of Paraná state between 1970 and 2010

    Directory of Open Access Journals (Sweden)

    Eduardo de Pintor

    2014-06-01

    Full Text Available The theory of demographic transition began with an effort of Frank Notestein (1945 to understand the demographic changes that were occurring in Western Europe since the late nineteenth century. The demographic transition is the transition between two scenarios of population growth, which changes the age structure of the population. The aim of the article is to discuss the evolution of population structure age of Paraná state between 1970 and 2010. The changes in the age structure of the Paraná indicate a reduction in the share of young population and increasing aging population, an increase in the relative weight of the elderly population. Public policies on education, health, social security and labor market should consider the current change in the age structure. Thus, the aim of this study was to analyze the change in the age structure of the population of the state of Paraná. For this we used data Censuses of the Brazilian Institute of Geography and Statistics (IBGE on the age distribution of urban and rural Paraná and its Mesoregions. It was concluded that the change in structure occurs group widespread in all Mesoregions state. However, it occurs unevenly between urban and rural population.

  13. Age-related changes in neural control of posture

    NARCIS (Netherlands)

    Papegaaij, Selma

    2016-01-01

    As we get older many physiological functions decline, including muscle strength, flexibility, and memory. Also in the aging brain there are changes, such as shrinkage of its volume. Since we need our brain to keep our balance while standing, it seems likely that these changes also affect our balance

  14. Change of translation teaching contents in the information age

    Institute of Scientific and Technical Information of China (English)

    倪宇红

    2016-01-01

    the development of information technology, especially that of multimedia and network communication technology, has offered good material conditions and effective support means for reform of translation teaching. The teaching contents of translation have undergone profound changes. This paper discusses these changes and advocates that teachers should adapt their teaching to the requirements of the information age.

  15. Age structure and dynamics of Zoysia japonica module population

    Institute of Scientific and Technical Information of China (English)

    DAIBao-qing; WANGYan

    2005-01-01

    The age structure of the natural Zoysia japonica clonal population at Qipan Mountain in Huishan Scenic Spot of Shenyang,Liaoning Province, China was studied using the morphological method in 2003 and 2004. The dynamics of leaves were recorded and the dynamics of tiller and rhizome in the growing season were observed. The results indicated that the rhizomes formed in different years changed in color and rigidity. Its internodes produced in autumn became shorter. The number of naked nodes changed with the tiller age.Rhizome and tiller characters were used as a foundation for judging the ages of modules in this study. The longevity of tiller and rhizome was 3 years at most. At the beginning of the growing season, 2-year-old tillers and rhizomes predominated. Then I -year-old tillers and rhizomes increased rapidly and became dominant in July. The proportion of buds to tillers on quantity was stable at about 30% in the mid-phase of the growing season and rose to about 50% in autumn. The seasonal dynamics of tiller, rhizome and bud was very important to guarantee the sustained existence of the Zoysia japonica population. The turnover of modules was the mechanism of sustaining the rejuvenation of the Zoysia japonica clonal population.

  16. Naming ability changes in physiological and pathological aging

    Directory of Open Access Journals (Sweden)

    Maria eCotelli

    2012-08-01

    Full Text Available Over the last two decades, age-related anatomical and functional brain changes have been characterised by evidence acquired primarily by means of non-invasive functional neuroimaging. These functional changes are believed to favour positive reorganisation driven by adaptations to system changes as compensation for cognitive decline. These functional modifications have been linked to residual brain plasticity mechanisms, suggesting that all areas of the brain remain plastic during physiological and pathological aging. A technique that can be used to investigate changes in physiological and pathological aging is non-invasive brain stimulation (NIBS. The present paper reviews studies that have applied NIBS in younger and older adults and in patients with dementia to track changes in the cerebral areas involved in a language task (naming. The results of this research suggest that the left frontal and temporal areas are crucial during naming. Moreover, it is suggested that in older adults and patients with dementia, the right prefrontal cortex is also engaged during naming tasks, and naming performance correlates with age and/or the degree of the pathological process. Potential theories underlying the bilateral involvement of the prefrontal cortex are discussed, and the relationship between the bilateral engagement of the prefrontal cortex and the age or degree of pathology is explored.

  17. Changing governance structures in South African agribusiness

    NARCIS (Netherlands)

    Doyer, O.T.; Haese, D' M.F.C.; Rooyen, van C.J.; Kirsten, J.F.; Haese, D' L.

    2008-01-01

    This article examines the changing governance structures in the South African agri-food sector. Changing legislative and market conditions forced agribusiness managers to rethink their governance structures to ensure the competitiveness of the agri-food sector. They had to adapt to the new structure

  18. Changes during aging and their association with malnutrition

    OpenAIRE

    Shilpa Amarya, MSc; Kalyani Singh, PhD; Manisha Sabharwal, PhD

    2015-01-01

    The aging process involves changes in physiological, pathological, social, and psychological conditions of a person. Nutrition is an important element of health among the elderly, and it affects the whole process of aging. The prevalence of malnutrition is increasing in this population and is associated with a decline in functional status, impaired muscle function, decreased bone mass, immune dysfunction, anemia, reduced cognitive function, poor wound healing, delayed recovery from surgery, h...

  19. Intra-individual Change in Personality Stability and Age

    OpenAIRE

    Terracciano, Antonio; McCrae, Robert R.; Costa, Paul T.

    2010-01-01

    The stability of individual differences in personality traits is typically examined at the group level with test-retest correlations across two assessments. For 684 subjects (age range 17–76) we computed individual coefficients from three sequential assessments to evaluate intra-individual (i.e., within-person) change in stability over time. For both trait and profile (ipsative) stability, results indicate that intra-individual stability increases up to age 30 and then plateaus. Neither demog...

  20. Changes during aging and their association with malnutrition

    Directory of Open Access Journals (Sweden)

    Shilpa Amarya, MSc

    2015-09-01

    Full Text Available The aging process involves changes in physiological, pathological, social, and psychological conditions of a person. Nutrition is an important element of health among the elderly, and it affects the whole process of aging. The prevalence of malnutrition is increasing in this population and is associated with a decline in functional status, impaired muscle function, decreased bone mass, immune dysfunction, anemia, reduced cognitive function, poor wound healing, delayed recovery from surgery, higher hospital readmission rates, and mortality. Due to changing socioeconomic environment, elderly people are often left alone to fend for themselves to maintain their health, which may interfere with the maintenance of a good nutritional status. Regular diagnosis of malnutrition among older patients increases the need for more education regarding nutritional status in older patients, and the purpose of this article is to provide information with an educational overview of essential nutritional aspect associated with changes in aging.

  1. Age-Related Changes in Trabecular and Cortical Bone Microstructure

    Directory of Open Access Journals (Sweden)

    Huayue Chen

    2013-01-01

    Full Text Available The elderly population has substantially increased worldwide. Aging is a complex process, and the effects of aging are myriad and insidious, leading to progressive deterioration of various organs, including the skeleton. Age-related bone loss and resultant osteoporosis in the elderly population increase the risk for fractures and morbidity. Osteoporosis is one of the most common conditions associated with aging, and age is an independent risk factor for osteoporotic fractures. With the development of noninvasive imaging techniques such as computed tomography (CT, micro-CT, and high resolution peripheral quantitative CT (HR-pQCT, imaging of the bone architecture provides important information about age-related changes in bone microstructure and estimates of bone strength. In the past two decades, studies of human specimens using imaging techniques have revealed decreased bone strength in older adults compared with younger adults. The present paper addresses recently studied age-related changes in trabecular and cortical bone microstructure based primarily on HR-pQCT and micro-CT. We specifically focus on the three-dimensional microstructure of the vertebrae, femoral neck, and distal radius, which are common osteoporotic fracture sites.

  2. Age-related changes in skin topography and microcirculation.

    Science.gov (United States)

    Li, Li; Mac-Mary, Sophie; Marsaut, David; Sainthillier, Jean Marie; Nouveau, Stéphanie; Gharbi, Tijani; de Lacharriere, Olivier; Humbert, Philippe

    2006-03-01

    Skin topography and microvasculature undergo characteristic changes with age. Although several non-invasive bioengineering methods are currently available to measure them quantitatively, few publications have referred to their relationship with age in different anatomical sites. This study was carried out to observe the age-related changes of the skin topography and skin microcirculation. The microrelief was assessed with special processing software from scanning by interference fringe profilometry of silicone replicas performed on two sites (volar forearm and back of hand) on 50 female volunteers (aged 20-74 years who consisted of ten probands in each decade). The superficial vascular network of both sites was assessed by videocapillaroscopy, and the subpapillary vascular plexus was studied with laser Doppler flowmetry. Skin color, which is affected by blood flow, was observed by colorimeter. The skin roughness and the mean height between peak and valley increased with age. There were statistically significant differences between the evaluated sites. This study also shows that the capillary loops in the dermal papillae decrease but the subpapillary plexus increase with age. The interference fringe profilometry associated with videocapillaroscopy may be useful and accurate to measure the efficacy of medical or cosmetic products to delay skin aging.

  3. Structural aging program -- a summary of activities, results, and conclusions

    International Nuclear Information System (INIS)

    Research has been conducted by the Oak Ridge National Laboratory to address aging management of nuclear power plant concrete structures. The purpose was to identify potential structural safety issues and acceptance criteria for use in continued service assessments. Primary program accomplishments have included formulation of a Structural Materials Information Center that contains data and information on the time variation of material properties under the influence of pertinent environmental stressors and aging factors for 144 materials, an aging assessment methodology to identify critical structures and degradation factors that can potentially impact their performance, guidelines and evaluation criteria for use in condition assessments of reinforced concrete structures, and a reliability-based methodology for current condition assessments and estimations of future performance of reinforced concrete nuclear power plant structures. In addition, the Structural Aging Program conducted in-depth evaluations of several nondestructive evaluation and repair-related technologies to develop guidance on their applicability

  4. Structural aging program -- a summary of activities, results, and conclusions

    Energy Technology Data Exchange (ETDEWEB)

    Naus, D.J.; Oland, C.B. [Oak Ridge National Lab., TN (United States); Ellingwood, B.R. [Johns Hopkins Univ., Baltimore, MD (United States)] [and others

    1997-01-01

    Research has been conducted by the Oak Ridge National Laboratory to address aging management of nuclear power plant concrete structures. The purpose was to identify potential structural safety issues and acceptance criteria for use in continued service assessments. Primary program accomplishments have included formulation of a Structural Materials Information Center that contains data and information on the time variation of material properties under the influence of pertinent environmental stressors and aging factors for 144 materials, an aging assessment methodology to identify critical structures and degradation factors that can potentially impact their performance, guidelines and evaluation criteria for use in condition assessments of reinforced concrete structures, and a reliability-based methodology for current condition assessments and estimations of future performance of reinforced concrete nuclear power plant structures. In addition, the Structural Aging Program conducted in-depth evaluations of several nondestructive evaluation and repair-related technologies to develop guidance on their applicability.

  5. Innovation, Productivity Growth, and Structural Change

    OpenAIRE

    Maier, H.

    1984-01-01

    This paper is concerned with three broad topics: first, changes in the conditions for productivity growth during the last decade; second, industrial innovation as a factor of productivity growth; and third, productivity as a factor of structural change.

  6. Trajectories of depressive symptoms in old age: Integrating age-, pathology-, and mortality-related changes.

    Science.gov (United States)

    Chui, Helena; Gerstorf, Denis; Hoppmann, Christiane A; Luszcz, Mary A

    2015-12-01

    Late life involves a variety of different challenges to well-being. This study extends and qualifies propositions drawn from the paradox of well-being in aging using 15-year longitudinal data on depressive symptoms from old and very old participants in the Australian Longitudinal Study of Ageing (Baseline N = 2,087; Mage = 78.69 years; range: 65-103 years; 49.40% women). We first examined age-related trajectories in depressive symptoms from young-old to oldest-old, taking into account (changes in) relevant correlates, pathology, and mortality; and, second, we investigated gender differences in these trajectories. Results revealed that age-related trajectories of depressive symptoms were predictive of mortality hazards. The unique predictive effects of both level of, and change in, depressive symptoms were independent of one another and held after taking into account education as well as changes in marital status, living arrangements, cognitive function, and illness burden. In addition, results indicated that depressive symptoms were elevated among participants suffering from arthritis, and increased with age more markedly in men than in women. In particular, the significant Age × Gender interaction indicated that the gender gap in depressive symptoms reduced from young-old to old-old and reversed in very old age when men showed more depressive symptoms than women. Qualifying the paradox of well-being in aging, findings demonstrated that depressive symptoms increased from young-old to oldest-old and suggest that age-, pathology-, and mortality-related changes should be examined in concert to advance our understanding of individual differences in depressive symptom trajectories in late life.

  7. Aging of concrete structures in nuclear power plants

    International Nuclear Information System (INIS)

    The Structural Aging (SAG) Program, sponsored by the US Nuclear Regulatory Commission (USNRC) and conducted by the Oak Ridge National Laboratory (ORNL), had the overall objective of providing the USNRC with an improved basis for evaluating nuclear power plant structures for continued service. The program consists of three technical tasks: materials property data base, structural component assessment/repair technology, and quantitative methodology for continued service determinations. Major accomplishments under the SAG Program during the first two years of its planned five-year duration have included: development of a Structural Materials Information Center and formulation of a Structural Aging Assessment Methodology for Concrete Structures in Nuclear Power Plants. 9 refs

  8. Audiometric changes with age in Hiroshima: a statistical study

    Energy Technology Data Exchange (ETDEWEB)

    Hollingsworth, J.W.; Ishii, Goro

    1960-10-01

    Audiometry observations were analyzed for 290 irradiated survivors of the 1945 atomic bomb in Hiroshima and in 293 nonirradiated subjects. The study was undertaken in order to determine the age changes in audiology in irradiated and nonirradiated subjects as well as to investigate the pattern of hearing levels in a Japanese population for comparison with patterns in Caucasians. The following statistical observations were made. Correlation between hearing levels for right and left ear. Correlation between hearing levels at various cycles. Changes in hearing levels by age and sex. The relation between age and decibel loss was not linear and correlation ratios with age were 0.45 to 0.72. Audiometry seems to be of some value as one of a battery of tests of physiologic aging designed for detection of irradiation induced nonspecific aging acceleration. In this relatively small sample, no differences in hearing acuity were detected in the atomic bomb survivors as compared with the control sample. 6 references, 3 figures, 9 tables.

  9. Handwriting changes due to aging and Parkinson's syndrome.

    Science.gov (United States)

    Walton, J

    1997-08-22

    Wills signed by elderly people are often contested on the grounds the the signature is different from their earlier specimen signatures. Neurological disease, which can affect handwriting, is very common and progressive amongst elderly people. Handwriting change due to old age and neurological disease is poorly understood. To better understand this subject, we carried out a large methodical study based on almost 200 handwriting specimens of Parkinson patients and age-matched controls. Interestingly, our findings indicate that some of the handwriting changes which occur in these populations tend to resemble forgery indicia although upon close inspection they are distinguishable from them. Thus, document examiners are urged to exercise caution in assessing purported forgeries on wills and other documents signed of written during older age or a writer suffering from neurological disease. PMID:9291592

  10. The challenges posed by climate change to successful ageing.

    Science.gov (United States)

    Wanka, A; Arnberger, A; Allex, B; Eder, R; Hutter, H-P; Wallner, P

    2014-08-01

    Ever since the 2003 heat wave that caused 70,000 heat deaths, the dramatic consequences of climate change and rising temperatures in Europe have become an intensively researched topic. During heat waves, the older urban adult population is at highest risk. The STOPHOT project is the first investigation in Austria to establish a comprehensive knowledge base on heat perception, awareness of heat risks and adaptive/coping behaviours among older adults. The main research questions include: (1) Does climate change endanger the chances of successful ageing in urban areas? (2) How do age, social inequalities and the living environment intersect with environmental stressors in affecting successful ageing? (3) Which heat adaption strategies do older adults deploy and to what extent can they mediate heat stress in an effort to increase chances of successful ageing under the conditions of climate change? The results indicate that climate change and rising temperatures are in fact one important determinant of whether and how an older person can maintain well-being in later life. Older adults (> 65 years) with a low socio-economic status and poor health conditions, who tend to be socially isolated, are most at risk. However, no 'heat island effect' of the residential environment could be found. How much a person suffers from heat stress is highly dependent on the adaption strategies deployed. Adaption strategies of older urban residents mostly centred on body-related measures, such as drinking more or wearing lighter clothes, and indoor-centred measures, particularly avoiding the outdoors. PMID:25119703

  11. The middle ear immune defense changes with age

    DEFF Research Database (Denmark)

    Nielsen, Michelle Christine; Friis, Morten; Martin-Bertelsen, Tomas;

    2016-01-01

    performed. Complementary DNA microarray technology was used to identify immune-related genes differentially expressed between the normal middle ear mucosa of young (10 days old) and adult rats (80 days old). Data were analyzed using tools of bioinformatics. A total of 260 age-related genes were identified......Otitis media is a common disease in childhood. In adults, the disease is relatively rare, but more frequently associated with complications. Possible reasons for this discrepancy are age-related differences in pathogen exposure, anatomy of the Eustachian tube and immune system. The objective...... of this study was to analyze the relationship between age and the mucosal immune system in the middle ear. It is hypothesized that genes involved in the middle ear immune system will change with age. A comprehensive assessment of these genetic differences using the techniques of complementary DNA has not been...

  12. Structural Change and Macrodynamic Capabilities

    OpenAIRE

    Araujo, Ricardo Azevedo; Teixeira, Joanilio Rodolpho

    2010-01-01

    In this paper we intend to study some mechanisms that block a rapid diffusion of technological progress from advanced to underdeveloped countries. In order to accomplish this task we focus on two approaches that challenge the view that technological gaps between rich and poor nations are diminishing. The first is the structural economic dynamic approach and the second is the evolutionary view. Both of them reveal that the elimination of the technological gaps between rich and poor nations is ...

  13. Size, longevity and cancer: age structure.

    Science.gov (United States)

    Wensink, Maarten J

    2016-09-14

    There is significant recent interest in Peto's paradox and the related problem of the evolution of large, long-lived organisms in terms of cancer robustness. Peto's paradox refers to the expectation that large, long-lived organisms have a higher lifetime cancer risk, which is not the case: a paradox. This paradox, however, is circular: large, long-lived organisms are large and long-lived because they are cancer robust. Lifetime risk, meanwhile, depends on the age distributions of both cancer and competing risks: if cancer strikes before competing risks, then lifetime risk is high; if not, not. Because no set of competing risks is generally prevalent, it is instructive to temporarily dispose of competing risks and investigate the pure age dynamics of cancer under the multistage model of carcinogenesis. In addition to augmenting earlier results, I show that in terms of cancer-free lifespan large organisms reap greater benefits from an increase in cellular cancer robustness than smaller organisms. Conversely, a higher cellular cancer robustness renders cancer-free lifespan more resilient to an increase in size. This interaction may be an important driver of the evolution of large, cancer-robust organisms. PMID:27629030

  14. The structural properties of sustainable, continuous change

    DEFF Research Database (Denmark)

    Håkonsson, Dorthe Døjbak; Klaas, Johann Peter; Carroll, Timothy

    2013-01-01

    this relationship by exploring what structural properties enable continuous change in inertia-generating organizations and what their performance consequences are in dynamic environments. The article has three main findings: First, employing managers who anticipate change is not enough to generate continuous change......; it is also necessary to raise both the rate of responsiveness and desired performance. Second, continuous change increases average organizational performance and reduces its variation. Third, organizations’ capacity for continuous change is counterintuitively limited by the organizations’ capacity to build...

  15. AGE STRUCTURES OF MODULES OF CLONAL PEATLAND SEDGE Carex middendorffii

    Institute of Scientific and Technical Information of China (English)

    BU Zhao-jun; YANG Yun-fei; H(a)kan RYDIN; LANG Hui-qing

    2005-01-01

    Age structure of a plant population carries important information on population dynamics. The traditional age classification of individuals by development phases could not explain the generation relationship neither between individuals nor between modules, and it could not accurately predict the future of population or the tendency of peatland evolution. In a peatland of the Xiao Hinggan Mountains, China, at the middle of the growth season,the age structures of 3 modules, ramets, active buds and rhizomes of a Carex middendo(fii clonal population were investigated, with the method of classifying age classes of ramets and active buds by counting generation quantity of tiller nodes, and classifying age classes of rhizomes by their real survival time. The quantity of vegetative ramets was dominant. Tiller nodes oframets can propagate vegetatively for a maximum of 3 generations. The population of ramets consisted of 3 age classes of ramets at the middle of the growth season, and showed a stable age structure. In the two sampling events, there was no significant difference between quantities and age structure of the population.The maximum age of an excavated rhizome was 12 years old. Rhizomes were classified in 8 age classes, and age classes 4-6 contributed most to the total biomass. There was no significant difference in total length and total biomass per unit area, or in biomass per unit length in rhizomes between the two samplings. Four age classes of active buds were recognized, and their number increased from July to August. The Carex middendorffii clonal population achieved regeneration by budding from the tiller nodes of ramets. The age structures of the 3 modules suggested that the Carex middendorffii clonal population could persist in the early development phase of the oligotrophic peatland in the Xiao Hinggan Mountains, but it could not be dominant. It also faces the risk to disappear from the community as the peatland develops further.

  16. Age estimation from physiological changes of teeth: A reliable age marker?

    Directory of Open Access Journals (Sweden)

    Nishant Singh

    2014-01-01

    Full Text Available Background: Age is an essential factor in establishing the identity of a person. Teeth are one of the most durable and resilient part of skeleton. Gustafson (1950 suggested the use of six retrogressive dental changes that are seen with increasing age. Aim: The aim of the study was to evaluate the results and to check the reliability of modified Gustafson′s method for determining the age of an individual. Materials and Methods: Total 70 patients in the age group of 20-65 years, undergoing extraction were included in this present work. The ground sections of extracted teeth were prepared and examined under the microscope. Modified Gustafson′s criteria were used for the estimation of age. Degree of attrition, root translucency, secondary dentin deposition, cementum apposition, and root resorption were measured. A linear regression formula was obtained using different statistical equations in a sample of 70 patients. Results: The mean age difference of total 70 cases studied was ±2.64 years. Difference of actual and calculated age was significant and was observed at 5% level of significance, that is, t-cal > t-tab (t-cal = 7.72. P < 0.05, indicates that the results were statistically significant. Conclusion: The present study concludes that Gustafson′s method is a reliable method for age estimation with some proposed modifications.

  17. Age-biased technological and organiszational change : firm-level evidence and management implications

    OpenAIRE

    Beckmann, Michael

    2007-01-01

    This paper examines the question, whether the growing use of new technologies and decentralized forms of work organization affects the age structure of workforces within firms. The initial idea behind this relationship is that technological and organizational change may not only be skill-biased, but also age-biased. Based on human capital theo–retical explanations that mainly focus on skill obsolescence in association with the need to acquire new skills, the hypothesis of an age–b...

  18. The changing face of orthostatic and neurocardiogenic syncope with age.

    LENUS (Irish Health Repository)

    Cooke, J

    2012-01-31

    AIM: Reports of the outcomes of syncope assessment across a broad spectrum of ages in a single population are scarce. It is our objective to chart the varying prevalence of orthostatic and neurocardiogenic syncope (NCS) as a patient ages. METHODS: This was a retrospective study. All consecutive patients referred to a tertiary referral syncope unit over a decade were included. Patients were referred with recurrent falls or orthostatic intolerance. Tilt tests and carotid sinus massage (CSM) were performed in accordance with best practice guidelines. RESULTS: A total of 3002 patients were included (1451 short tilt, 127 active stand, 1042 CSM and 382 prolonged tilt). Ages ranged from 11 to 91 years with a median (IQR) of 75 (62-81) years. There were 1914 females; 1088 males. Orthostatic hypotension (OH) was the most commonly observed abnormality (test positivity of 60.3%). Those with OH had a median (IQR) age of 78 (71-83) years. Symptomatic patients were significantly younger than asymptomatic (P = 0.03). NCS demonstrated a bimodal age distribution. Of 194 patients with carotid sinus hypersensitivity, the median age (IQR) was 77 (68-82) years. Those with vasovagal syncope (n = 80) had a median (IQR) age of 30 (19-44) years. There were 57 patients with isolated postural orthostatic tachycardia syndrome. Of the total patients, 75% were female. They had a median (IQR) age of 23 (17-29) years. CONCLUSION: We have confirmed, in a single population, a changing pattern in the aetiology of syncope as a person ages. The burden of disease is greatest in the elderly.

  19. Age-related changes in behavior in C57BL/6J mice from young adulthood to middle age

    OpenAIRE

    Shoji, Hirotaka; Takao, Keizo; Hattori, Satoko; Miyakawa, Tsuyoshi

    2016-01-01

    Background Aging is considered to be associated with progressive changes in the brain and its associated sensory, motor, and cognitive functions. A large number of studies comparing young and aged animals have reported differences in various behaviors between age-cohorts, indicating behavioral dysfunctions related to aging. However, relatively little is known about behavioral changes from young adulthood to middle age, and the effect of age on behavior during the early stages of life remains ...

  20. Structural changes concurrent with ferromagnetic transition

    Institute of Scientific and Technical Information of China (English)

    Yang Sen; Bao Hui-Xin; Zhou Chao; Wang Yu; Ren Xiao-Bing; Song Xiao-Ping; Yoshitaka Matsushita

    2013-01-01

    Ferromagnetic transition has generally been considered to involve only an ordering of magnetic moment with no change in the host crystal structure or symmetry,as evidenced by a wealth of crystal structure data from conventional X-ray diffractometry (XRD).However,the existence of magnetostriction in all known ferromagnetic systems indicates that the magnetic moment is coupled to the crystal lattice; hence there is a possibility that magnetic ordering may cause a change in crystal structure.With the development of high-resolution synchrotron XRD,more and more magnetic transitions have been found to be accompanied by simultaneous structural changes.In this article,we review our recent progress in understanding the structural change at a ferromagnetic transition,including synchrotron XRD evidence of structural changes at the ferromagnetic transition,a phenomenological theory of crystal structure changes accompanying ferromagnetic transitions,new insight into magnetic morphotropic phase boundaries (MPB) and so on.Two intriguing implications of non-centric symmetry in the ferromagnetic phase and the first-order nature of ferromagnetic transition are also discussed here.In short,this review is intended to give a self-consistent and logical account of structural change occurring simultaneously with a ferromagnetic transition,which may provide new insight for developing highly magneto-responsive materials.

  1. Age- and stroke-related skeletal muscle changes: a review for the geriatric clinician.

    Science.gov (United States)

    Sions, Jaclyn Megan; Tyrell, Christine M; Knarr, Brian A; Jancosko, Angela; Binder-Macleod, Stuart A

    2012-01-01

    Independently, aging and stroke each have a significant negative impact on skeletal muscle, but the potential cumulative effects of aging and stroke have not been explored. Optimal interventions for individuals post stroke may include those that specifically target skeletal muscle. Addressing changes in muscles may minimize activity limitations and enhance participation post stroke. This article reviews the impact of aging and stroke on muscle morphology and composition, including fiber atrophy, reductions in muscle cross-sectional area, changes in muscle fiber distributions, and increases in intramuscular fat. Relationships between changes in muscle structure, muscle function, and physical mobility are reviewed. Clinical recommendations that preserve and enhance skeletal muscle in the aging adult and individuals post stroke are discussed. Future research directions that include systematic comparison of the differences in skeletal muscle between younger and older adults who have sustained a stroke are suggested.

  2. Investigation of unique hue setting changes with ageing

    Institute of Scientific and Technical Information of China (English)

    Chenyang Fu; Kaida Xiao; Dimosthenis Karatzas; Sophie Wuerger

    2011-01-01

    Clromatic sensitivity along the protan, deutan, and tritan lines and the loci of the unique hues (red, green,yellow, blue) for a very large sample (n = 185) of colour-normal observers ranging from 18 to 75 years of age are assessed. Visual judgments are obtained under normal viewing conditions using colour patches on self-luminous display under controlled adaptation conditions. Trivector discrimination thresholds show an increase as a function of age along the protan, deutan, and tritan axes, with the largest increase present along the tritan line, less pronounced shifts in unique hue settings are also observed. Based on the chromatic (protan, deutan, tritan) thresholds and using scaled cone signals, we predict the unique hue changes with ageing. A dependency on age for unique red and unique yellow for predicted hue angle is found. We conclude that the chromatic sensitivity deteriorates significantly with age, whereas the appearance of unique hues is much less affected, remaining almost constant despite the known changes in the ocular media.%@@ Clromatic sensitivity along the protan, deutan, and tritan lines and the loci of the unique hues (red, green,yellow, blue) for a very large sample (n = 185) of colour-normal observers ranging from 18 to 75 years of age are assessed.Visual judgments are obtained under normal viewing conditions using colour patches on self-luminous display under controlled adaptation conditions.Trivector discrimination thresholds show an increase as a function of age along the protan, deutan, and tritan axes, with the largest increase present along the tritan line, less pronounced shifts in unique hue settings are also observed.

  3. Age-Related Changes in Demand–Withdraw Communication Behaviors

    OpenAIRE

    Holley, Sarah R.; Haase, Claudia M.; Levenson, Robert W.

    2013-01-01

    Demand–withdraw communication is a set of conflict-related behaviors in which one partner blames or pressures while the other partner withdraws or avoids. The present study examined age-related changes in these behaviors longitudinally over the course of later life stages. One hundred twenty-seven middle-aged and older long-term married couples were observed at 3 time points across 13 years as they engaged in a conversation about an area of relationship conflict. Husbands’ and wives’ demand–w...

  4. The Healthy Ageing Model: health behaviour change for older adults.

    Science.gov (United States)

    Potempa, Kathleen M; Butterworth, Susan W; Flaherty-Robb, Marna K; Gaynor, William L

    2010-01-01

    Proposed is a model of primary care for older adults with chronic health conditions that focuses on active engagement in health care. The Healthy Ageing Model is anchored in established theory on motivation and health behaviour change. The model draws on empirical and applied clinical underpinnings in such diverse areas as health promotion and education, treatment of addictions or obesity, management of chronic diseases, goal-setting, and coaching techniques. The conceptual foundation for the Healthy Ageing Model is described first, followed by a brief description of the key characteristics of the model. In conclusion, suggestions are offered for the clinical application and for further developing the model.

  5. Age related changes in histomorphology of medium sized muscular artery

    International Nuclear Information System (INIS)

    The aim of this study was to contribute to the knowledge of histomorphometric changes which are associated with increasing age in local population, with the experience obtained in the dissection on cadavers. Study Design: Cross-sectional comparative study Place and Duration of Study: The study was carried out at the department of Anatomy, Army Medical College Rawalpindi in collaboration with Forensic departments of various medical institutes where cadavers were brought for autopsy, spanning from 15 Feb 2010 to 15 Aug 2010. Material and Methods: A total of forty cadavers from local population (Punjab and Khyber Pakhtunkhwa) were dissected and specimen (Common hepatic artery) (CHA) were obtained. Two age groups, one below the age of forty years (1 to 39 years) and the other above the age of forty years (40 to 70 years) were made. The specimen were processed and stained with Hematoxylin and Eosin. Using a microscope with 10 X objective, micrometry was done and data of intima thickness (IT), media thickness (MT) and intima media thickness (IMT) was noted. Results: After comparing the two age groups, statistically significant difference was found between the IT (p value <0.01). The mean values of media failed to attain any statistical difference. No statistically significant difference was found in the IMT of the two age groups. Conclusion: Increase in intima thickness was found while MT and IMT did not show any statistical difference. (author)

  6. Change with age in regression construction of fat percentage for BMI in school-age children.

    Science.gov (United States)

    Fujii, Katsunori; Mishima, Takaaki; Watanabe, Eiji; Seki, Kazuyoshi

    2011-01-01

    In this study, curvilinear regression was applied to the relationship between BMI and body fat percentage, and an analysis was done to see whether there are characteristic changes in that curvilinear regression from elementary to middle school. Then, by simultaneously investigating the changes with age in BMI and body fat percentage, the essential differences in BMI and body fat percentage were demonstrated. The subjects were 789 boys and girls (469 boys, 320 girls) aged 7.5 to 14.5 years from all parts of Japan who participated in regular sports activities. Body weight, total body water (TBW), soft lean mass (SLM), body fat percentage, and fat mass were measured with a body composition analyzer (Tanita BC-521 Inner Scan), using segmental bioelectrical impedance analysis & multi-frequency bioelectrical impedance analysis. Height was measured with a digital height measurer. Body mass index (BMI) was calculated as body weight (km) divided by the square of height (m). The results for the validity of regression polynomials of body fat percentage against BMI showed that, for both boys and girls, first-order polynomials were valid in all school years. With regard to changes with age in BMI and body fat percentage, the results showed a temporary drop at 9 years in the aging distance curve in boys, followed by an increasing trend. Peaks were seen in the velocity curve at 9.7 and 11.9 years, but the MPV was presumed to be at 11.9 years. Among girls, a decreasing trend was seen in the aging distance curve, which was opposite to the changes in the aging distance curve for body fat percentage.

  7. Change with age in regression construction of fat percentage for BMI in school-age children.

    Science.gov (United States)

    Fujii, Katsunori; Mishima, Takaaki; Watanabe, Eiji; Seki, Kazuyoshi

    2011-01-01

    In this study, curvilinear regression was applied to the relationship between BMI and body fat percentage, and an analysis was done to see whether there are characteristic changes in that curvilinear regression from elementary to middle school. Then, by simultaneously investigating the changes with age in BMI and body fat percentage, the essential differences in BMI and body fat percentage were demonstrated. The subjects were 789 boys and girls (469 boys, 320 girls) aged 7.5 to 14.5 years from all parts of Japan who participated in regular sports activities. Body weight, total body water (TBW), soft lean mass (SLM), body fat percentage, and fat mass were measured with a body composition analyzer (Tanita BC-521 Inner Scan), using segmental bioelectrical impedance analysis & multi-frequency bioelectrical impedance analysis. Height was measured with a digital height measurer. Body mass index (BMI) was calculated as body weight (km) divided by the square of height (m). The results for the validity of regression polynomials of body fat percentage against BMI showed that, for both boys and girls, first-order polynomials were valid in all school years. With regard to changes with age in BMI and body fat percentage, the results showed a temporary drop at 9 years in the aging distance curve in boys, followed by an increasing trend. Peaks were seen in the velocity curve at 9.7 and 11.9 years, but the MPV was presumed to be at 11.9 years. Among girls, a decreasing trend was seen in the aging distance curve, which was opposite to the changes in the aging distance curve for body fat percentage. PMID:21483178

  8. Changes in intracellular calcium in brain cells of aged rats

    Institute of Scientific and Technical Information of China (English)

    Yu Li; Yunpeng Cao

    2008-01-01

    BACKGROUND: Studies have shown that voltage-dependent calcium influx, and enhancement of certain calcium-dependent processes in neurons, is related to aging. OBJECTIVE: To observe changes in intracellular calcium ([Ca2+]i) in neurons of aged rats, and to compare with young rats. DESIGN, TIME AND SETTING: A randomized control experiment of neurophysiology was performed at the Central Laboratory of School of Pharmaceutical Science, China Medical University from June to August 2004. MATERIALS: Ten male, healthy, Wistar rats, 19 months old, were selected for the aged group. Ten male, 3-month-old, Wistar rats were selected for the young control group. Fura-2/AM was provided by the Institute of Pharmaceutical Research of Chinese Academy of Medical Sciences, and the F-2000 fluorospectrophotometer was a product of Hitachi, Japan. METHODS: Fluorescence Fura-2 spectrophotometer was used to measure [Ca2+]i in acutely dissociated brain cells of aged and young rats. The concentration of extracellular potassium was controlled by adding different volumes of chloridated potassium solution of high concentration. MAIN OUTCOME MEASURES: [Ca2+]i in neurons of young and aged rats in the presence of 1 mmol/L extracellular calcium concentration and 0 mmol/L (resting state), 5, 10, 20, and 40 mmol/L extracellular potassium. Absolute increase of [Ca2+]i in neurons of young and aged rats when extraceUular potassium was 5,10,20, 40 mmol/L. RESULTS: In the presence of 1 mmol/L extracellular Ca2+ and 0 mmol/L (resting state), 5, 10, 20, and 40 mmol/L extracellular potassium, [Ca2+]i in the neurons of aged rats was significantly less than that in young rats (P 0.05). CONCLUSION: The overload of [Ca2+]i in neurons of aged rats is greater than that of young rats under the same circumstances.

  9. Factor Endowment, Structural Change, and Economic Growth

    OpenAIRE

    Che, Natasha Xingyuan

    2010-01-01

    This paper aims (1) to test the endowment-based structural change theory proposed by recent studies such as Acemoglu & Guerrieri (2008) and Ju, Lin & Wang (2009); and (2) to explore the linkage between structural coherence and economic growth. By structural coherence, I refer to the degree that a country’s industrial structure optimally reflects its factor endowment fundamentals. Using data from 27 industries across 15 countries, I examine whether higher capital endowment is associated w...

  10. Age-dependent change in urine proteome of healthy individuals

    Science.gov (United States)

    Dobrokhotov, Igor; Liudmila Pastushkova, MRS.; Larina, Irina; Kononikhin, Alexey

    It was analyzed the protein composition of urine samples obtained from twenty Russian cosmonauts and thirty-eight healthy volunteers, that have been selected for the experiments simulating the physiological effects of microgravity. The special sample preparation was performed, followed by liquid chromatography-mass spectrometry. Liquid chromatography-mass spectrometry of the minor proteins was performed on a nano-HPLC Agilent 1100 system (Agilent Technologies Inc., USA) in combination with a LTQ-FT Ultra mass spectrometer (Thermo Electron, Germany). List of masses derived peptides and they fragments have used for search and identification of proteins by database IPI-human (international index of protein) using the program Mascot (MS version 2.0.04 , UK) according to the following criteria: 1 - enzyme-trypsin; 2 - peptide tol. ± 5 ppm; 3 - MS / MS tol. 0.5Da. From list of proteins obtained as a result Mascot-search it was selected only those proteins that were identified based on 2 or more peptides with the rating more than 24. Analysis of the list of proteins was performed using software developed in the laboratory of VA Ivanisenko (ICG SB RAS) Age of healthy individuals was ranged from 18 to 54 years. Depending on the age, the data were divided into three groups: those relating to the group of persons under 25 years (youth and mature age 1), 25-40 years (mature age 2) and 40-54 years (mature age 3) It was detected reliable changes in the number of proteins among groups depending of the age. It was found that the minimum number of different proteins were detected in the urine of the group of young patients (under 25 years old) , and the maximum - was observed in the group of middle-aged persons (25 to 40 years). When the proteins were compared according to their molecular mass it was revealed that in the older group (40-54 years ) there is noticeably smaller percentage of high molecular weight proteins than in groups of young and middle aged persons. Thus

  11. Evaluations of mosquito age grading techniques based on morphological changes.

    Science.gov (United States)

    Hugo, L E; Quick-Miles, S; Kay, B H; Ryan, P A

    2008-05-01

    Evaluations were made of the accuracy and practicality of mosquito age grading methods based on changes to mosquito morphology; including the Detinova ovarian tracheation, midgut meconium, Polovodova ovariole dilatation, ovarian injection, and daily growth line methods. Laboratory maintained Aedes vigilax (Skuse) and Culex annulirostris (Skuse) females of known chronological and physiological ages were used for these assessments. Application of the Detinova technique to laboratory reared Ae. vigilax females in a blinded trial enabled the successful identification of nulliparous and parous females in 83.7-89.8% of specimens. The success rate for identifying nulliparous females increased to 87.8-98.0% when observations of ovarian tracheation were combined with observations of the presence of midgut meconium. However, application of the Polovodova method only enabled 57.5% of nulliparous, 1-parous, 2-parous, and 3-parous Ae. vigilax females to be correctly classified, and ovarian injections were found to be unfeasible. Poor correlation was observed between the number of growth lines per phragma and the calendar age of laboratory reared Ae. vigilax females. In summary, morphological age grading methods that offer simple two-category predictions (ovarian tracheation and midgut meconium methods) were found to provide high-accuracy classifications, whereas methods that offer the separation of multiple age categories (ovariolar dilatation and growth line methods) were found to be extremely difficult and of low accuracy. The usefulness of the morphology-based methods is discussed in view of the availability of new mosquito age grading techniques based on cuticular hydrocarbon and gene transcription changes. PMID:18533427

  12. Intra-individual Change in Personality Stability and Age

    Science.gov (United States)

    Terracciano, Antonio; McCrae, Robert R.; Costa, Paul T.

    2009-01-01

    The stability of individual differences in personality traits is typically examined at the group level with test-retest correlations across two assessments. For 684 subjects (age range 17–76) we computed individual coefficients from three sequential assessments to evaluate intra-individual (i.e., within-person) change in stability over time. For both trait and profile (ipsative) stability, results indicate that intra-individual stability increases up to age 30 and then plateaus. Neither demographic variables (sex, ethnicity, education, and secular trends), nor the standing on the five major dimensions of personality, were predictors of change in trait stability. Contrary to results from studies of adolescents, personality “maturity” was unrelated to personality stability in adulthood. These findings support the notion that personality stability plateaus early in adulthood. PMID:20305728

  13. Oxidative modification of proteins: age-related changes.

    Science.gov (United States)

    Chakravarti, Bulbul; Chakravarti, Deb N

    2007-01-01

    Aging is a complex biological phenomenon which involves progressive loss of different physiological functions of various tissues of living organisms. It is the inevitable fate of life and is a major risk factor for death and different pathological disorders. Based on a wide variety of studies performed in humans as well as in various animal models and microbial systems, reactive oxygen species (ROS) are believed to play a key role in the aging process. The production of ROS is influenced by cellular metabolic activities as well as environmental factors. ROS can react with all major biological macromolecules such as carbohydrates, nucleic acids, lipids, and proteins. Since, in general, proteins are the key molecules that play the ultimate role in various structural and functional aspects of living organisms, this review will focus on the age-related oxidative modifications of proteins as well as on mechanism for removal or repair of the oxidized proteins. The topics covered include protein oxidation as a marker of oxidative stress, experimental evidence indicating the role of ROS in protein oxidation, protein carbonyl content, enzymatic degradation of oxidized proteins, and effects of caloric restriction on protein oxidation in the context of aging. Finally, we will discuss different strategies which have been or can be undertaken to slow down the oxidative damage of proteins and the aging process.

  14. Age-related changes in the respiratory system

    OpenAIRE

    Lesauskaite, Vita; Ebejer, Martin J.

    1999-01-01

    This article summarises the main structural and physiological changes which take place in the lung from young adulthood to senescence. An understanding of these changes helps the clinician to correctly interpret some results of radiology and pulmonary function frequently seen in clinical practice. An appreciation of the altered physiology and the consequent reduction in pulmonary reserve should alert the physician to the need for a more critical evaluation of the various respiratory parameter...

  15. Arterial structure and function in vascular ageing: are you as old as your arteries?

    Science.gov (United States)

    Thijssen, Dick H J; Carter, Sophie E; Green, Daniel J

    2016-04-15

    Advancing age may be the most potent independent predictor of future cardiovascular events, a relationship that is not fully explained by time-related changes in traditional cardiovascular risk factors. Since some arteries exhibit differential susceptibility to atherosclerosis, generalisations regarding the impact of ageing in humans may be overly simplistic, whereas in vivo assessment of arterial function and health provide direct insight. Coronary and peripheral (conduit, resistance and skin) arteries demonstrate a gradual, age-related impairment in vascular function that is likely to be related to a reduction in endothelium-derived nitric oxide bioavailability and/or increased production of vasoconstrictors (e.g. endothelin-1). Increased exposure and impaired ability for defence mechanisms to resist oxidative stress and inflammation, but also cellular senescence processes, may contribute to age-related changes in vascular function and health. Arteries also undergo structural changes as they age. Gradual thickening of the arterial wall, changes in wall content (i.e. less elastin, advanced glycation end-products) and increase in conduit artery diameter are observed with older age and occur similarly in central and peripheral arteries. These changes in structure have important interactive effects on artery function, with increases in small and large arterial stiffness representing a characteristic change with older age. Importantly, direct measures of arterial function and structure predict future cardiovascular events, independent of age or other cardiovascular risk factors. Taken together, and given the differential susceptibility of arteries to atherosclerosis in humans, direct measurement of arterial function and health may help to distinguish between biological and chronological age-related change in arterial health in humans.

  16. Structural Changes in Chinese Food Preferences

    OpenAIRE

    Hovhannisyan, Vardges; Gould, Brian W.

    2012-01-01

    The article tests for structural food preference change in urban China using province-level panel data from 2002 to 2010. We employ the Generalized Quadratic Almost Ideal Demand System to represent consumer preferences and estimate demand for seven food groups in a dynamic setting. This relaxes many of the restrictions on the demand models used in the literature on structural preference change. Our findings suggest that Chinese food preferences are continuing to evolve.

  17. Age-related changes in hypocretin (orexin) immunoreactivity in the cat brainstem.

    Science.gov (United States)

    Zhang, Jian Hua; Sampogna, Sharon; Morales, Francisco R; Chase, Michael H

    2002-03-15

    Terminals of hypothalamic hypocretin-containing neurons are observed within brainstem nuclei involved in the control of sleep and wakefulness. Because aged humans, cats and other species exhibit changes in sleep and wakefulness in old age, we were interested in examining age-related changes in hypocretin/orexin projections to the following brainstem regions which are associated with the regulation of sleep and wakefulness: the dorsal raphe nucleus, the laterodorsal tegmental nucleus, the pedunculo-pontine tegmental nucleus and the locus coeruleus. Based upon the results of immunohistochemical determinations, in all the regions examined, round or oval "spot-like" structures were observed in aged cats. Many of these "spot-like" structures resembled enlarged varicosities of a nature that would be expected to disrupt hypocretin neurotransmission. In addition, a site-specific decrease in immunostaining was observed in the locus coeruleus in old cats compared with adult controls; this result likely reflects a decrease in the number of labeled fibers, which indicates that there occurs a degeneration of hypocretinergic function in conjunction with old age. The proceeding changes may account for some of sleep-wake disturbance which are observed in aged animals as well as elderly humans. PMID:11879811

  18. Travelling Wave Solutions in Multigroup Age-Structured Epidemic Models

    Science.gov (United States)

    Ducrot, Arnaut; Magal, Pierre; Ruan, Shigui

    2010-01-01

    Age-structured epidemic models have been used to describe either the age of individuals or the age of infection of certain diseases and to determine how these characteristics affect the outcomes and consequences of epidemiological processes. Most results on age-structured epidemic models focus on the existence, uniqueness, and convergence to disease equilibria of solutions. In this paper we investigate the existence of travelling wave solutions in a deterministic age-structured model describing the circulation of a disease within a population of multigroups. Individuals of each group are able to move with a random walk which is modelled by the classical Fickian diffusion and are classified into two subclasses, susceptible and infective. A susceptible individual in a given group can be crisscross infected by direct contact with infective individuals of possibly any group. This process of transmission can depend upon the age of the disease of infected individuals. The goal of this paper is to provide sufficient conditions that ensure the existence of travelling wave solutions for the age-structured epidemic model. The case of two population groups is numerically investigated which applies to the crisscross transmission of feline immunodeficiency virus (FIV) and some sexual transmission diseases.

  19. Demographic analysis from summaries of an age-structured population

    Science.gov (United States)

    Link, W.A.; Royle, J. Andrew; Hatfield, J.S.

    2003-01-01

    Demographic analyses of age-structured populations typically rely on life history data for individuals, or when individual animals are not identified, on information about the numbers of individuals in each age class through time. While it is usually difficult to determine the age class of a randomly encountered individual, it is often the case that the individual can be readily and reliably assigned to one of a set of age classes. For example, it is often possible to distinguish first-year from older birds. In such cases, the population age structure can be regarded as a latent variable governed by a process prior, and the data as summaries of this latent structure. In this article, we consider the problem of uncovering the latent structure and estimating process parameters from summaries of age class information. We present a demographic analysis for the critically endangered migratory population of whooping cranes (Grus americana), based only on counts of first-year birds and of older birds. We estimate age and year-specific survival rates. We address the controversial issue of whether management action on the breeding grounds has influenced recruitment, relating recruitment rates to the number of seventh-year and older birds, and examining the pattern of variation through time in this rate.

  20. The middle ear immune defense changes with age.

    Science.gov (United States)

    Nielsen, Michelle Christine; Friis, Morten; Martin-Bertelsen, Tomas; Winther, Ole; Friis-Hansen, Lennart; Cayé-Thomasen, Per

    2016-01-01

    Otitis media is a common disease in childhood. In adults, the disease is relatively rare, but more frequently associated with complications. Possible reasons for this discrepancy are age-related differences in pathogen exposure, anatomy of the Eustachian tube and immune system. The objective of this study was to analyze the relationship between age and the mucosal immune system in the middle ear. It is hypothesized that genes involved in the middle ear immune system will change with age. A comprehensive assessment of these genetic differences using the techniques of complementary DNA has not been performed. Complementary DNA microarray technology was used to identify immune-related genes differentially expressed between the normal middle ear mucosa of young (10 days old) and adult rats (80 days old). Data were analyzed using tools of bioinformatics. A total of 260 age-related genes were identified, of which 51 genes were involved in the middle ear mucosal immune system. Genes related to the innate immune system, including alpha-defensin, calcium-binding proteins S100A9 and S100A8, were upregulated in young rats, whereas genes related to the adaptive immune system, including CD3 molecules, zeta-chain T-cell receptor-associated protein kinase and linker of activated T-cells, were upregulated in the adult. This study concludes that the normal middle ear immune system changes with age. Genes related to the innate immune system are upregulated in young rats, whereas genes related to the adaptive immune system are upregulated in adults.

  1. Age-associated metabolic and morphologic changes in mitochondria of individual mouse and hamster oocytes.

    Directory of Open Access Journals (Sweden)

    Fatma Simsek-Duran

    Full Text Available BACKGROUND: In human oocytes, as in other mammalian ova, there is a significant variation in the pregnancy potential, with approximately 20% of oocyte-sperm meetings resulting in pregnancies. This frequency of successful fertilization decreases as the oocytes age. This low proportion of fruitful couplings appears to be influenced by changes in mitochondrial structure and function. In this study, we have examined mitochondrial biogenesis in both hamster (Mesocricetus auratus and mouse (Mus musculus ova as models for understanding the effects of aging on mitochondrial structure and energy production within the mammalian oocyte. METHODOLOGY/PRINCIPAL FINDINGS: Individual metaphase II oocytes from a total of 25 young and old mice and hamsters were collected from ovarian follicles after hormone stimulation and prepared for biochemical or structural analysis. Adenosine triphosphate levels and mitochondrial DNA number were determined within individual oocytes from young and old animals. In aged hamsters, oocyte adenosine triphosphate levels and mitochondrial DNA molecules were reduced 35.4% and 51.8%, respectively. Reductions of 38.4% and 44% in adenosine triphosphate and mitochondrial genomes, respectively, were also seen in aged mouse oocytes. Transmission electron microscopic (TEM analysis showed that aged rodent oocytes had significant alterations in mitochondrial and cytoplasmic lamellae structure. CONCLUSIONS/SIGNIFICANCE: In both mice and hamsters, decreased adenosine triphosphate in aged oocytes is correlated with a similar decrease in mtDNA molecules and number of mitochondria. Mitochondria in mice and hamsters undergo significant morphological change with aging including mitochondrial vacuolization, cristae alterations, and changes in cytoplasmic lamellae.

  2. Age-Related Changes in Skeletal Muscle of Cattle.

    Science.gov (United States)

    Costagliola, A; Wojcik, S; Pagano, T B; De Biase, D; Russo, V; Iovane, V; Grieco, E; Papparella, S; Paciello, O

    2016-03-01

    Sarcopenia, the age-related loss of muscle mass and strength, is a multifactorial condition that represents a major healthcare concern for the elderly population. Although its morphologic features have been extensively studied in humans, animal models, and domestic and wild animals, only a few reports about spontaneous sarcopenia exist in other long-lived animals. In this work, muscle samples from 60 healthy Podolica-breed old cows (aged 15-23 years) were examined and compared with muscle samples from 10 young cows (3-6 years old). Frozen sections were studied through standard histologic and histoenzymatic procedures, as well as by immunohistochemistry, immunofluorescence, and Western blot analysis. The most prominent age-related myopathic features seen in the studied material included angular fiber atrophy (90% of cases), mitochondrial alterations (ragged red fibers, 70%; COX-negative fibers, 60%), presence of vacuolated fibers (75%), lymphocytic (predominantly CD8+) inflammation (40%), and type II selective fiber atrophy (40%). Immunohistochemistry revealed increased expression of major histocompatibility complex I in 36 cases (60%) and sarcoplasmic accumulations of β-amyloid precursor protein-positive material in 18 cases (30%). In aged cows, muscle atrophy was associated with accumulation of myostatin. Western blot analysis indicated increased amount of both proteins-myostatin and β-amyloid precursor protein-in muscles of aged animals compared with controls. These findings confirm the presence of age-related morphologic changes in cows similar to human sarcopenia and underline the possible role of amyloid deposition and subsequent inflammation in muscle senescence. PMID:26869152

  3. Aging and demographic plasticity in response to experimental age structures in honeybees (Apis mellifera L).

    Science.gov (United States)

    Rueppell, Olav; Linford, Robyn; Gardner, Preston; Coleman, Jennifer; Fine, Kari

    2008-08-01

    Honeybee colonies are highly integrated functional units characterized by a pronounced division of labor. Division of labor among workers is mainly age-based, with younger individuals focusing on in-hive tasks and older workers performing the more hazardous foraging activities. Thus, experimental disruption of the age composition of the worker hive population is expected to have profound consequences for colony function. Adaptive demography theory predicts that the natural hive age composition represents a colony-level adaptation and thus results in optimal hive performance. Alternatively, the hive age composition may be an epiphenomenon, resulting from individual life history optimization. We addressed these predictions by comparing individual worker longevity and brood production in hives that were composed of a single age cohort, two distinct age cohorts, and hives that had a continuous, natural age distribution. Four experimental replicates showed that colonies with a natural age composition did not consistently have a higher life expectancy and/or brood production than the single cohort or double cohort hives. Instead, a complex interplay of age structure, environmental conditions, colony size, brood production, and individual mortality emerged. A general trade-off between worker life expectancy and colony productivity was apparent, and the transition from in-hive tasks to foraging was the most significant predictor of worker lifespan irrespective of the colony age structure. We conclude that the natural age structure of honeybee hives is not a colony-level adaptation. Furthermore, our results show that honeybees exhibit pronounced demographic plasticity in addition to behavioral plasticity to react to demographic disturbances of their societies.

  4. Consequences of stand age and species’ functional trait changes on ecosystem water use of forests

    Energy Technology Data Exchange (ETDEWEB)

    Ewers, Brent; Bond-Lamberty, Benjamin; Mackay, D. Scott

    2011-07-22

    We tested whether using stomatal conductance could capture the dynamic in transpiration with forest age. To do this we by answered the question “If we chose a reference stomatal conductance from one stand age of the entire chronosequence to put into a model, would modeled transpiration be biased from the other ages?” with a resounding yes. We found that obtaining the right stomatal conductance was crucial for accurate models in two different chronosequences. This strongly suggests that stomatal conductance is the appropriate integrator of inter- and intra-species change in tree transpiration with forest age. If we had tried to use a single reference canopy stomatal conductance, it would not have been able to capture the variability in transpiration with stand age despite the suggestion that hydraulic limitation was consistently acting on the trees; the situation is even more complex in many boreal systems, where a transition to nonstomatal bryophytes may occur over the course of succession. Because we used a biophysical approach, even if our and other researchers’ chronosequences do not fit the assumptions, the results are still useful. Further, our synthesis of sap flux based estimates of tree transpiration showing a large dynamic suggest that our approach to modeling is crucial in the face of anthropogenic changes to forest age structure. We have now provided the framework for a mechanistically rigorous yet simple approach based on simple tree hydraulics to measuring and modeling stand transpiration with changing forest age and/or species composition.

  5. EXPRESSION PATTERNS OF ESTROGEN RECEPTORS IN THE CENTRAL AUDITORY SYSTEM CHANGE IN PREPUBERTAL AND AGED MICE

    Science.gov (United States)

    Charitidi, K.; Frisina, R. D.; Vasilyeva, O. N.; Zhu, X.; Canlon, B.

    2011-01-01

    Estrogens are important in the development, maintenance and physiology of the CNS. Several studies have shown their effects on the processing of hearing in both males and females, and these effects, in part, are thought to result from regulation of the transcription of genes via their classical estrogen receptor (ER) pathway. In order to understand the spatiotemporal changes that occur with age, we have studied the expression of ERs in the central auditory pathway in prepubertal and aged CBA mice with immunohistochemistry. In prepubertal mice a clear dichotomy was noted between the expression of ERα and ERβ. ERβ-positive neurons were found in the metencephalon whereas the majority of ERα was found in mesencephalon, diencephalon or the telencephalon. In the aged animals a different pattern of ER expression was found in terms of location and overall intensity. These age-induced changes in the expression pattern were generally not uniform, suggesting that region-specific mechanisms regulate the ERs’ age-related expression. Neither the prepubertal nor the aged animals showed sex differences in any auditory structure. Our results demonstrate different age-dependent spatial and temporal changes in the pattern of expression of ERα and ERβ, suggesting that each ER type may be involved in distinct roles across the central auditory pathway in different periods of maturation. PMID:20736049

  6. Qualitative attentional changes with age in doing two tasks at once.

    Science.gov (United States)

    Maquestiaux, François

    2016-02-01

    Does practice reduce, or even eliminate, aging effects on the attentional limitations responsible for dual-task interference? The studies reviewed in this article show that age differences reliably persist after extensive practice. Strikingly, dual-task interference remains larger among older adults even in training conditions that allow them to achieve single-task performance as fast as younger adults. These findings demonstrate that age deficits in attentional functioning are robust. Advancing age also can be accompanied by improvements in cognitive functioning, such as in the ability to access the lexicon without attention (i.e., automatically), due to lifelong experience with word reading. Future research needs to establish whether age deficits in central attention are due to structural changes that are irreversible or reversible to some extent. PMID:26106060

  7. Evolution of pancreas in aging: degenerative variation or early changes of disease?

    Science.gov (United States)

    Chantarojanasiri, Tanyaporn; Hirooka, Yoshiki; Ratanachu-Ek, Thawee; Kawashima, Hiroki; Ohno, Eizaburo; Goto, Hidemi

    2015-04-01

    Pancreatic changes in aging have been described for many decades. They involve not only pancreatic parenchyma but also pancreatic ductal, microscopic, and exocrine functional changes. There have been many studies of these changes based on pathology and various imaging modalities, as well as functional studies. The pancreatic volume was found to decrease with advancing age, with a higher incidence of pancreatic steatosis, as demonstrated in autopsy and imaging studies. The pancreatic ductal structure has been described with wide ranges of normal variation, but many studies have shown a tendency toward enlargement with advancing age. By endoscopic ultrasound imaging, the aging pancreas may exhibit abnormal findings similar to chronic pancreatitis. Microscopically, there has been evidence of patchy lobular fibrosis and papillary hyperplasia and demonstrable k-ras mutation in both normal and dysplastic ductal mucosa. The evidence of pancreatic exocrine insufficiency has yielded conflicting results, but most studies have shown a tendency toward decreased pancreatic exocrine function in the elderly. Differentiating pancreatic change in the elderly from early chronic pancreatitis may be difficult as there are limited studies to compare these two conditions in terms of structural and functional changes.

  8. Do hassles and uplifts change with age? Longitudinal findings from the VA normative aging study.

    Science.gov (United States)

    Aldwin, Carolyn M; Jeong, Yu-Jin; Igarashi, Heidi; Spiro, Avron

    2014-03-01

    To examine emotion regulation in later life, we contrasted the modified hedonic treadmill theory with developmental theories, using hassles and uplifts to assess emotion regulation in context. The sample was 1,315 men from the VA Normative Aging Study aged 53 to 85 years, who completed 3,894 observations between 1989 and 2004. We computed 3 scores for both hassles and uplifts: intensity (ratings reflecting appraisal processes), exposure (count), and summary (total) scores. Growth curves over age showed marked differences in trajectory patterns for intensity and exposure scores. Although exposure to hassles and uplifts decreased in later life, intensity scores increased. Group-based modeling showed individual differences in patterns of hassles and uplifts intensity and exposure, with relative stability in uplifts intensity, normative nonlinear changes in hassles intensity, and complex patterns of individual differences in exposure for both hassles and uplifts. Analyses with the summary scores showed that emotion regulation in later life is a function of both developmental change and contextual exposure, with different patterns emerging for hassles and uplifts. Thus, support was found for both hedonic treadmill and developmental change theories, reflecting different aspects of emotion regulation in late life. PMID:24660796

  9. White and grey matter changes in the language network during healthy aging.

    Directory of Open Access Journals (Sweden)

    Yanhui Yang

    Full Text Available Neural structures change with age but there is no consensus on the exact processes involved. This study tested the hypothesis that white and grey matter in the language network changes during aging according to a "last in, first out" process. The fractional anisotropy (FA of white matter and cortical thickness of grey matter were measured in 36 participants whose ages ranged from 55 to 79 years. Within the language network, the dorsal pathway connecting the mid-to-posterior superior temporal cortex (STC and the inferior frontal cortex (IFC was affected more by aging in both FA and thickness than the other dorsal pathway connecting the STC with the premotor cortex and the ventral pathway connecting the mid-to-anterior STC with the ventral IFC. These results were independently validated in a second group of 20 participants whose ages ranged from 50 to 73 years. The pathway that is most affected during aging matures later than the other two pathways (which are present at birth. The results are interpreted as showing that the neural structures which mature later are affected more than those that mature earlier, supporting the "last in, first out" theory.

  10. Localizing age-related individual differences in a hierarchical structure

    OpenAIRE

    Salthouse, Timothy A.

    2004-01-01

    Data from 33 separate studies were combined to create an aggregate data set consisting of 16 cognitive variables and 6832 different individuals who ranged between 18 and 95 years of age. Analyses were conducted to determine where in a hierarchical structure of cognitive abilities individual differences associated with age, gender, education, and self-reported health could be localized. The results indicated that each type of individual difference characteristic exhibited a d...

  11. Report on aging of nuclear power plant reinforced concrete structures

    Energy Technology Data Exchange (ETDEWEB)

    Naus, D.J.; Oland, C.B. [Oak Ridge National Lab., TN (United States); Ellingwood, B.R. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Civil Engineering

    1996-03-01

    The Structural Aging Program provides the US Nuclear Regulatory Commission with potential structural safety issues and acceptance criteria for use in continued service assessments of nuclear power plant safety-related concrete structures. The program was organized under four task areas: Program Management, Materials Property Data Base, Structural Component Assessment/Repair Technology, and Quantitative Methodology for Continued Service Determinations. Under these tasks, over 90 papers and reports were prepared addressing pertinent aspects associated with aging management of nuclear power plant reinforced concrete structures. Contained in this report is a summary of program results in the form of information related to longevity of nuclear power plant reinforced concrete structures, a Structural Materials Information Center presenting data and information on the time variation of concrete materials under the influence of environmental stressors and aging factors, in-service inspection and condition assessments techniques, repair materials and methods, evaluation of nuclear power plant reinforced concrete structures, and a reliability-based methodology for current and future condition assessments. Recommendations for future activities are also provided. 308 refs., 61 figs., 50 tabs.

  12. Report on aging of nuclear power plant reinforced concrete structures

    International Nuclear Information System (INIS)

    The Structural Aging Program provides the US Nuclear Regulatory Commission with potential structural safety issues and acceptance criteria for use in continued service assessments of nuclear power plant safety-related concrete structures. The program was organized under four task areas: Program Management, Materials Property Data Base, Structural Component Assessment/Repair Technology, and Quantitative Methodology for Continued Service Determinations. Under these tasks, over 90 papers and reports were prepared addressing pertinent aspects associated with aging management of nuclear power plant reinforced concrete structures. Contained in this report is a summary of program results in the form of information related to longevity of nuclear power plant reinforced concrete structures, a Structural Materials Information Center presenting data and information on the time variation of concrete materials under the influence of environmental stressors and aging factors, in-service inspection and condition assessments techniques, repair materials and methods, evaluation of nuclear power plant reinforced concrete structures, and a reliability-based methodology for current and future condition assessments. Recommendations for future activities are also provided. 308 refs., 61 figs., 50 tabs

  13. Age-Dependent Changes in Pb Concentration in Human Teeth.

    Science.gov (United States)

    Fischer, Agnieszka; Wiechuła, Danuta

    2016-09-01

    The result of exposure to Pb is its accumulation in mineralized tissues. In human body, they constitute a reservoir of approx. 90 % of the Pb reserve. The conducted research aimed at determining the accumulation of Pb in calcified tissues of permanent teeth. The concentration of Pb in 390 samples of teeth taken from a selected group of Polish people was determined using the AAS method. Average concentration of Pb in teeth amounted to 14.3 ± 8.18 μg/g, range of changes: 2.21-54.8 μgPb/g. Accumulation of Pb in human body was determined based on changes in Pb concentration in teeth of subjects aged 13-84 years. It was found that in calcified tissues of teeth, the increase in concentration of Pb that occurs with age is a statistically significant process (p = 0.02, the ANOVA Kruskal-Wallis test). It was determined that the annual increase in concentration of Pb in tissues of teeth is approx. 0.1 μg/g. Moreover, a different course of changes in Pb concentration in tissues of teeth in people born in different years was observed. The level of Pb concentration in teeth of the oldest subjects (>60 years) decreased for those born in the 1930s compared to those in the 1950s. Teeth from younger persons (<60 years) were characterized by an increasing level of Pb concentration. The analysis of changes of Pb indicates that for low exposure, a relatively greater accumulation of Pb concentration in calcified tissues of teeth can occur. PMID:26888348

  14. An age-structured population balance model for microbial dynamics

    Directory of Open Access Journals (Sweden)

    Duarte M.V.E.

    2003-01-01

    Full Text Available This work presents an age-structured population balance model (ASPBM for a bioprocess in a continuous stirred-tank fermentor. It relates the macroscopic properties and dynamic behavior of biomass to the operational parameters and microscopic properties of cells. Population dynamics is governed by two time- and age-dependent density functions for living and dead cells, accounting for the influence of substrate and dissolved oxygen concentrations on cell division, aging and death processes. The ASPBM described biomass and substrate oscillations in aerobic continuous cultures as experimentally observed. It is noteworthy that a small data set consisting of nonsegregated measurements was sufficient to adjust a complex segregated mathematical model.

  15. An age structured model for obesity prevalence dynamics in populations

    Directory of Open Access Journals (Sweden)

    Gilberto González Parra

    2010-08-01

    Full Text Available Objective. Modeling the correlation of the development of obesity in a population with age and time and predict the dynamics of the correlation of the development of obesity in a population with age and time under different scenarios in Valencia (Spain. Materials and methods. An age structured mathematical model is used to describe the future dynamics of obesity prevalence for different ages in human population with excess weight. Simulation of the model with parameters estimated using the Health Survey of the Region of Valencia 2000 (4.319 interviews and Health Survey of the Region of Valencia 2005 (4.012 interviews. The model considers only overweight and obese populations since these subpopulations are the most relevant on obesity health concern. Results. The model allows predicting and studying the prevalence of obesity for each age. Results showed an increasing trend of obesity in the following years in well accordance with the trend observed in several countries. Conclusions. Based on the numerical simulations it is possible to conclude that the age structured mathematical model is suitable to forecast the obesity epidemic in each age group in different countries. Additionally, this type of models may be applied to study other characteristics of other populations such animal populations.

  16. Structural Changes in Serbian Industry during Transition

    Directory of Open Access Journals (Sweden)

    Ivan Nikolić

    2013-07-01

    Full Text Available Transition is a complex process whereby a country in transition is stimulating structural changes wishing to achieve economic growth and improved social wellbeing. In this paper the authors aim to show that during transition in Serbia there such changes in the structure of manufacturing industry occurred, which resulted with only modest ​​growth that in fact was slower than in other transitional countries. By the means of theoretical and empirical approach – deductive methods, statistical and mathematical evaluation the authors have come to conclusion that structural changes did not improve industry branches like the hi-tech industry that contribute the most to PPP generation. At the same time, some low productive industries have gained on importance, therefore keeping the standard on the low levels without possibility to rapidly converge towards EU average, which was set as an ultimate goal of transition in Serbia.

  17. Magnetic resonance fiber density mapping of age-related white matter changes

    International Nuclear Information System (INIS)

    Objectives: To introduce fiber density mapping (FDM) for investigation of age-related white matter (WM) changes and to compare its capabilities with conventional diffusion tensor imaging (DTI) post-processing. Methods: DTI data with 1.9 mm3 isotropic voxels were acquired from 44 healthy volunteers (18–88 years) at 3 T. FDM is a 3-step approach which includes diagonalization of the diffusion tensor, fiber reconstruction for the whole brain, and calculation of fiber density (FD) values. Maps of fractional anisotropy (FA) and mean diffusivity (MD) were additionally calculated. Voxel-based analyses were performed to determine volume clusters of significant correlation with age. Bivariate linear regression models and Hotelling–Williams tests were used to detect significant differences between correlations. Results: FDM detected a larger WM volume affected by age-related changes concomitant with fewer significant clusters compared to FA and MD. This indicates that WM alterations due to normal aging occur rather globally than locally. FD values showed a significant stronger correlation with age in frontal lobes (prefrontal and precentral gyrus), limbic lobes (cingulate and parahippocampal gyrus), the corpus callosum (genu) and temporal lobes. Conclusions: FDM shows higher sensitivity for detection of age-related WM changes because it includes all surrounding fiber structures into the evaluation of each DTI data voxel.

  18. Magnetic resonance fiber density mapping of age-related white matter changes

    Energy Technology Data Exchange (ETDEWEB)

    Stadlbauer, Andreas, E-mail: andi@nmr.at [MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, A-3100 St. Poelten (Austria); Department of Neurosurgery, University of Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen (Germany); Ganslandt, Oliver [Department of Neurosurgery, University of Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen (Germany); Salomonowitz, Erich [MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, A-3100 St. Poelten (Austria); Buchfelder, Michael [Department of Neurosurgery, University of Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen (Germany); Hammen, Thilo [Department of Neurology, Epilepsy Center, University of Erlangen-Nuremberg, Schwabachanlage 6, D-90429 Erlangen (Germany); Bachmair, Johanna [MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, A-3100 St. Poelten (Austria); Eberhardt, Knut [Krankenhaus Schloss Werneck, MRT-Kompetenzzentrum, Balthasar-Neumann-Platz 1, D-97440 Werneck (Germany)

    2012-12-15

    Objectives: To introduce fiber density mapping (FDM) for investigation of age-related white matter (WM) changes and to compare its capabilities with conventional diffusion tensor imaging (DTI) post-processing. Methods: DTI data with 1.9 mm{sup 3} isotropic voxels were acquired from 44 healthy volunteers (18–88 years) at 3 T. FDM is a 3-step approach which includes diagonalization of the diffusion tensor, fiber reconstruction for the whole brain, and calculation of fiber density (FD) values. Maps of fractional anisotropy (FA) and mean diffusivity (MD) were additionally calculated. Voxel-based analyses were performed to determine volume clusters of significant correlation with age. Bivariate linear regression models and Hotelling–Williams tests were used to detect significant differences between correlations. Results: FDM detected a larger WM volume affected by age-related changes concomitant with fewer significant clusters compared to FA and MD. This indicates that WM alterations due to normal aging occur rather globally than locally. FD values showed a significant stronger correlation with age in frontal lobes (prefrontal and precentral gyrus), limbic lobes (cingulate and parahippocampal gyrus), the corpus callosum (genu) and temporal lobes. Conclusions: FDM shows higher sensitivity for detection of age-related WM changes because it includes all surrounding fiber structures into the evaluation of each DTI data voxel.

  19. On the world's ice ages and changing environments

    International Nuclear Information System (INIS)

    All known ice ages during the earth's history are reviewed. The oldest glaciation occurred around 2.3 billion years ago, followed by a series of large glaciations 950-650, 450-430 and 310-270 million years ago. Continental drift played a major role in these long-term climatic changes. The present Quaternary ice age actually began 17 million years ago, when a large ice mass grew over Antarctica. A detailed account is given of the climatic fluctuations during the Quaternary period (over 2.5 million years). Different stratigraphic records, and the relationship of climatic variations to orbital forcing are discussed. Large environmental changes took place in the course of the climate oscillations. Large ice sheets waxed and waned, global sea-levels fluctuated, forests disappeared from many regions during cold times and advanced during favourable times. The ice masses depressed the earth's crust markedly, and this then rose rapidly when the ice melted. The extent of glacial erosion is also discussed. Finally the postglacial climatic history of the earth is described and the consequences of the possible greenhouse effect are considered.(orig.)

  20. THE CHANGING STRUCTURE OF NEBRASKA AGRICULTURE 1974 - 1982

    OpenAIRE

    Frederick, A.L. (Roy); Johnson, Bruce B.

    1985-01-01

    This report focuses on changes in the Nebraska farm sector from 1974 to 1982. Items of major interest include number, size, and types of farms; resource use and output; tenure patterns; age of farm operators; forms of farm business organization; and capital investment. A Gini Index procedure is used to measure shifts in concentration of certain structural variables. Data sources are Censuses of Agriculture, with emphasis on the 1982, 1978, and 1974 Censuses. The number of Nebraska farms decli...

  1. Change in Family Structure and Rates of Violent Juvenile Delinquency

    OpenAIRE

    Fry, Jeannie A.

    2010-01-01

    This paper addresses the question: Have the changes in family structure in the U.S. become a catalyst for juvenile delinquency? For this research, I use existing statistics for my three independent variables: divorce rates, rate of working mothers with children under age 18, percent female-headed households. My dependent variable, juvenile violent crime rates, is measured using data from the Office of Juvenile Justice and Delinquency Prevention. My control variables consist of the followin...

  2. Structural change and industrial policy in Turkey

    OpenAIRE

    Atiyas, İzak; Atiyas, Izak; Bakış, Ozan; Bakis, Ozan

    2013-01-01

    This paper presents evidence on structural change in Turkey and provides an overview of the evolution of industrial policy in the last three decades. We show that Turkey has experienced substantial growth in labor productivity in the last decade and that this has been associated with substantial change in the composition of value added and employment both in the overall economy and within the manufacturing industry. Using sectoral national accounts data we decompose aggregate productivity g...

  3. Estimating Structural Change in Linear Simultaneous Equations

    OpenAIRE

    Huang Weihong; Zhang Yang

    2004-01-01

    Tests and estimation for changes in the coefficients of linear regression models, particularly the analysis of covariance and the Chow tests, are well known to econometricians and are widely used. This paper demonstrates that analogous estimation can also be constructed in simultaneous equation models when equations are estimated by common estimator like OLS, 2SLS and LIML. In the present paper, we discuss the problem of estimating structural changes in equations from a simultaneous structura...

  4. An age-structured extension to the vectorial capacity model.

    Directory of Open Access Journals (Sweden)

    Vasiliy N Novoseltsev

    Full Text Available BACKGROUND: Vectorial capacity and the basic reproductive number (R(0 have been instrumental in structuring thinking about vector-borne pathogen transmission and how best to prevent the diseases they cause. One of the more important simplifying assumptions of these models is age-independent vector mortality. A growing body of evidence indicates that insect vectors exhibit age-dependent mortality, which can have strong and varied affects on pathogen transmission dynamics and strategies for disease prevention. METHODOLOGY/PRINCIPAL FINDINGS: Based on survival analysis we derived new equations for vectorial capacity and R(0 that are valid for any pattern of age-dependent (or age-independent vector mortality and explore the behavior of the models across various mortality patterns. The framework we present (1 lays the groundwork for an extension and refinement of the vectorial capacity paradigm by introducing an age-structured extension to the model, (2 encourages further research on the actuarial dynamics of vectors in particular and the relationship of vector mortality to pathogen transmission in general, and (3 provides a detailed quantitative basis for understanding the relative impact of reductions in vector longevity compared to other vector-borne disease prevention strategies. CONCLUSIONS/SIGNIFICANCE: Accounting for age-dependent vector mortality in estimates of vectorial capacity and R(0 was most important when (1 vector densities are relatively low and the pattern of mortality can determine whether pathogen transmission will persist; i.e., determines whether R(0 is above or below 1, (2 vector population growth rate is relatively low and there are complex interactions between birth and death that differ fundamentally from birth-death relationships with age-independent mortality, and (3 the vector exhibits complex patterns of age-dependent mortality and R(0 ∼ 1. A limiting factor in the construction and evaluation of new age

  5. Brain volumetric changes and cognitive ageing during the eighth decade of life.

    Science.gov (United States)

    Ritchie, Stuart J; Dickie, David Alexander; Cox, Simon R; Valdes Hernandez, Maria Del C; Corley, Janie; Royle, Natalie A; Pattie, Alison; Aribisala, Benjamin S; Redmond, Paul; Muñoz Maniega, Susana; Taylor, Adele M; Sibbett, Ruth; Gow, Alan J; Starr, John M; Bastin, Mark E; Wardlaw, Joanna M; Deary, Ian J

    2015-12-01

    Later-life changes in brain tissue volumes--decreases in the volume of healthy grey and white matter and increases in the volume of white matter hyperintensities (WMH)--are strong candidates to explain some of the variation in ageing-related cognitive decline. We assessed fluid intelligence, memory, processing speed, and brain volumes (from structural MRI) at mean age 73 years, and at mean age 76 in a narrow-age sample of older individuals (n = 657 with brain volumetric data at the initial wave, n = 465 at follow-up). We used latent variable modeling to extract error-free cognitive levels and slopes. Initial levels of cognitive ability were predictive of subsequent brain tissue volume changes. Initial brain volumes were not predictive of subsequent cognitive changes. Brain volume changes, especially increases in WMH, were associated with declines in each of the cognitive abilities. All statistically significant results were modest in size (absolute r-values ranged from 0.114 to 0.334). These results build a comprehensive picture of macrostructural brain volume changes and declines in important cognitive faculties during the eighth decade of life.

  6. Age-related striatal BOLD changes without changes in behavioral loss aversion

    Directory of Open Access Journals (Sweden)

    Hans C Breiter

    2015-04-01

    Full Text Available Loss aversion (LA, the idea that negative valuations have a higher psychological impact than positive ones, is considered an important variable in consumer research. The literature on aging and behavior suggests older individuals may show more LA, although it is not clear if this is an effect of aging in general (as in the continuum from age 20 and 50 years, or of the state of older age (e.g., past age 65 years. We also have not yet identified the potential biological effects of aging on the neural processing of LA. In the current study we used a cohort of subjects with a 30 year range of ages, and performed whole brain functional MRI (fMRI to examine the ventral striatum/nucleus accumbens (VS/NAc response during a passive viewing of affective faces with model-based fMRI analysis incorporating behavioral data from a validated approach/avoidance task with the same stimuli. Our a priori focus on the VS/NAc was based on (1 the VS/NAc being a central region for reward/aversion processing, (2 its activation to both positive and negative stimuli, (3 its reported involvement with tracking LA. LA from approach/avoidance to affective faces showed excellent fidelity to published measures of LA. Imaging results were then compared to the behavioral measure of LA using the same affective faces. Although there was no relationship between age and LA, we observed increasing neural differential sensitivity (NDS of the VS/NAc to avoidance responses (negative valuations relative to approach responses (positive valuations with increasing age. These findings suggest that a central region for reward/aversion processing changes with age, and may require more activation to produce the same LA behavior as in younger individuals, consistent with the idea of neural efficiency observed with high IQ individuals showing less brain activation to complete the same task.

  7. Association of structural global brain network properties with intelligence in normal aging.

    Directory of Open Access Journals (Sweden)

    Florian U Fischer

    Full Text Available Higher general intelligence attenuates age-associated cognitive decline and the risk of dementia. Thus, intelligence has been associated with cognitive reserve or resilience in normal aging. Neurophysiologically, intelligence is considered as a complex capacity that is dependent on a global cognitive network rather than isolated brain areas. An association of structural as well as functional brain network characteristics with intelligence has already been reported in young adults. We investigated the relationship between global structural brain network properties, general intelligence and age in a group of 43 cognitively healthy elderly, age 60-85 years. Individuals were assessed cross-sectionally using Wechsler Adult Intelligence Scale-Revised (WAIS-R and diffusion-tensor imaging. Structural brain networks were reconstructed individually using deterministic tractography, global network properties (global efficiency, mean shortest path length, and clustering coefficient were determined by graph theory and correlated to intelligence scores within both age groups. Network properties were significantly correlated to age, whereas no significant correlation to WAIS-R was observed. However, in a subgroup of 15 individuals aged 75 and above, the network properties were significantly correlated to WAIS-R. Our findings suggest that general intelligence and global properties of structural brain networks may not be generally associated in cognitively healthy elderly. However, we provide first evidence of an association between global structural brain network properties and general intelligence in advanced elderly. Intelligence might be affected by age-associated network deterioration only if a certain threshold of structural degeneration is exceeded. Thus, age-associated brain structural changes seem to be partially compensated by the network and the range of this compensation might be a surrogate of cognitive reserve or brain resilience.

  8. Entrepreneurship, structural change, and economic growth

    NARCIS (Netherlands)

    Noseleit, Florian

    2013-01-01

    The ability to adjust to structural change is vital to economic development, and entries can be active participants in this process. While the importance of factor reallocations for growth is widely discussed, the role of entrepreneurs in managing these reallocations is currently not well understood

  9. Migraine and structural changes in the brain

    DEFF Research Database (Denmark)

    Bashir, Asma; Lipton, Richard B; Ashina, Sait;

    2013-01-01

    To evaluate the association between migraine without aura (MO) and migraine with aura (MA) and 3 types of structural brain abnormalities detected by MRI: white matter abnormalities (WMAs), infarct-like lesions (ILLs), and volumetric changes in gray and white matter (GM, WM) regions....

  10. Capturing the age and spatial structures of migration

    NARCIS (Netherlands)

    Rogers, A; Raymer, J; Willekens, F

    2002-01-01

    In this paper we model the structures found in the level (generation) and allocation (distribution) components of age-specific and origin-destination-specific migration flows. For the examples, we examine the regional migration patterns in the USA for four periods: 1955-60, 1965-70, 1975-80, and 198

  11. Internal structure changes of eyelash induced by eye makeup.

    Science.gov (United States)

    Fukami, Ken-Ichi; Inoue, Takafumi; Kawai, Tomomitsu; Takeuchi, Akihisa; Uesugi, Kentaro; Suzuki, Yoshio

    2014-01-01

    To investigate how eye makeup affects eyelash structure, internal structure of eyelashes were observed with a scanning X-ray microscopic tomography system using synchrotron radiation light source. Eyelash samples were obtained from 36 Japanese women aged 20-70 years and whose use of eye makeup differed. Reconstructed cross-sectional images showed that the structure of the eyelash closely resembled that of scalp hair. The eyelash structure is changed by use of eye makeup. There was a positive correlation between the frequency of mascara use and the degree of cracking in cuticle. The positive correlation was also found between the frequency of mascara use and the porosity of the cortex. By contrast, the use of eyelash curler did not affect the eyelash structure with statistical significance.

  12. Age-Biased Technological and Organizational Change: Firm-Level Evidence and Management Implications

    OpenAIRE

    Beckmann, Michael

    2007-01-01

    This paper examines the question, whether the growing use of new technologies and decentralized forms of work organization affects the age structure of workforces within firms. The initial idea behind this relationship is that technological and organizational change may not only be skill–biased, but also age–biased. Based on human capital theo–retical explanations that mainly focus on skill obsolescence in association with the need to acquire new skills, the hypothesis of an...

  13. BLOOD PRESSURE CHANGE WITH AGE IN SALT-SENSITIVE TEENAGERS

    Institute of Scientific and Technical Information of China (English)

    Tao Ye; Zhi-quan Liu; Jian-jun Mu; Xi-han Fu; Jun Yang; Bao-lin Gao; Xiao-hong Zhang

    2004-01-01

    Objective To observe blood pressure change with age in salt-sensitive teenagers whose salt sensitivity were determined by repeated testing.Methods Salt sensitivity was determined through intravenous infusion of normal saline combined with volume-depletion by oral diuretic furosemide in 55 teenagers. After five years, salt sensitivity was re-examined and subject blood pressure was followed up. Blood pressure changes in salt-sensitive teenagers were compared to that of non-salt sensitive teenagers over five years.Results After 5 years, the repetition rate of salt sensitivity determined by intravenous saline loading is 92.7%. In teenagers with salt sensitivity on the baseline, both the systolic blood pressure increments and increment rates were much higher than non-salt sensitive teenagers (12.7±12.1 mmHg vs. 2.8±5.2 mmHg, P< 0.01; 12.2%± 12.0% vs. 2.5% ±4.4%, P< 0.001,respectively). There was a similar trend for diastolic blood pressure (8.4 ± 6.4 mmHg vs. 3.7 ± 6.4 mmHg, P = 0.052; 13.2% ±10.6 % vs. 6.8%± 10.1%, P = 0.053, respectively).Conclusions Salt sensitivity determined by intravenous saline loading showed good reproducibility. Blood pressure increments with age were much higher in salt-sensitive teenagers than non-salt sensitive teenagers, especially in terms of systolic blood pressure.

  14. Remodeling of chromatin structure in senescent cells and its potential impact on tumor suppression and aging

    OpenAIRE

    Adams, Peter D

    2007-01-01

    Cellular senescence is an important tumor suppression process, and a possible contributor to tissue aging. Senescence is accompanied extensive changes in chromatin structure. In particular, many senescent cells accumulate specialized domains of facultative heterochromatin, called Senescence Associated Heterochromatin Foci (SAHF), which are thought to repress expression of proliferation-promoting genes, thereby contributing to senescence-associated proliferation arrest. This article reviews ou...

  15. The effects of age structure on economic growth: An application of probabilistic forecasting to India

    OpenAIRE

    Prskawetz, Alexia; Kögel, Tomas; Warren C. Sanderson; Scherbov, Sergei

    2004-01-01

    During recent years there has been an increasing awareness of the explanatory power of demographic variables in economic growth regressions. We estimate a new model of the effects of age structure change on economic growth. We use the new model and recent probabilistic demographic projections for India to derive the uncertainty of predicted economic growth rates caused by the uncertainty in demographic developments.

  16. Reciprocal Changes in Phosphoenolpyruvate Carboxykinase and Pyruvate Kinase with Age Are a Determinant of Aging in Caenorhabditis elegans.

    Science.gov (United States)

    Yuan, Yiyuan; Hakimi, Parvin; Kao, Clara; Kao, Allison; Liu, Ruifu; Janocha, Allison; Boyd-Tressler, Andrea; Hang, Xi; Alhoraibi, Hanna; Slater, Erin; Xia, Kevin; Cao, Pengxiu; Shue, Quinn; Ching, Tsui-Ting; Hsu, Ao-Lin; Erzurum, Serpil C; Dubyak, George R; Berger, Nathan A; Hanson, Richard W; Feng, Zhaoyang

    2016-01-15

    Aging involves progressive loss of cellular function and integrity, presumably caused by accumulated stochastic damage to cells. Alterations in energy metabolism contribute to aging, but how energy metabolism changes with age, how these changes affect aging, and whether they can be modified to modulate aging remain unclear. In locomotory muscle of post-fertile Caenorhabditis elegans, we identified a progressive decrease in cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C), a longevity-associated metabolic enzyme, and a reciprocal increase in glycolytic pyruvate kinase (PK) that were necessary and sufficient to limit lifespan. Decline in PEPCK-C with age also led to loss of cellular function and integrity including muscle activity, and cellular senescence. Genetic and pharmacologic interventions of PEPCK-C, muscle activity, and AMPK signaling demonstrate that declines in PEPCK-C and muscle function with age interacted to limit reproductive life and lifespan via disrupted energy homeostasis. Quantifications of metabolic flux show that reciprocal changes in PEPCK-C and PK with age shunted energy metabolism toward glycolysis, reducing mitochondrial bioenergetics. Last, calorie restriction countered changes in PEPCK-C and PK with age to elicit anti-aging effects via TOR inhibition. Thus, a programmed metabolic event involving PEPCK-C and PK is a determinant of aging that can be modified to modulate aging.

  17. Relating Age Change and Behavior to Job Requirements.

    Science.gov (United States)

    Schaie, K. Warner

    The Age Discrimination in Employment Act has been amended to outlaw mandatory retirement at any age. However, the act permits employers to impose a specific retirement age if there is a bona fide occupational qualification (BFOQ) which cannot be met by all or most individuals. Imposition of BFOQ mandatory retirement ages by employers has led to…

  18. [Changes in employment, retirement age and fertility: their effects on economic dependency and per capita income].

    Science.gov (United States)

    Bravo, J H

    1991-04-01

    This article provides a very simplified analysis of the impact of changes in unemployment, retirement age, and fertility on economic dependency and per capita income in Latin America. The macroeconomic consequences of variations in age structure have received a little recent attention among Latin American researchers and policymakers, partly because of the lack of simple but rigorous analytical models to orient research. This analysis is simplified in that it focuses on changes in age distribution but does not explicitly consider effects of changes in population size, even though in reality the 2 types of changes are interrelated. The analysis has also been simplified by not taking into account any type of causal interaction between the demographic and economic variables analyzed; only the most elementary accounting relations between them are utilized. The 1st section defines the concept of economic dependency, specifies the effects of changes in its demographic and economic components, and establishes a simple link between the dependency ratio and per capita income. These and other derivations in the following sections permit evaluation of the impact of changes in employment, retirement age, and fertility on the dependency ratio and per capita income. The work concludes with a synthesis and general discussion, including a theoretical consideration of the effects of interactions among components. Only the most important equations are presented in the main text, but all variables, equations, and relations are defined and derived in the appendix. 6 countries were studied to illustrate the relationships in the context of the demographic diversity of Latin America. Argentina and Cuba represented countries in an advanced stage of the demographic transition, Chile and Mexico represented an intermediate phase, and Bolivia and Peru represented countries at the beginning of the transition. Results of decomposition of changes in dependency and income due to each of the

  19. Traveling wave dispersal in partially sedentary age-structured populations

    CERN Document Server

    Le, Thuc Manh; Van Minh, Nguyen

    2010-01-01

    In this paper we present a thorough study on the existence of traveling waves in a mathematical model of dispersal in a partially sedentary age-structured population. This type of model was first proposed by Veit and Lewis in [{\\it Am. Nat.}, {\\bf 148} (1996), 255-274]. We choose the fecundity function to be the Beverton-Holt type function. We extend the theory of traveling waves in the population genetics model of Weinberger in [{\\it SIAM J. Math. Anal.}, {\\bf 13} (1982), 353-396] to the case when migration depends on age groups and a fraction of the population does not migrate.

  20. Changes to collagen structure during leather processing.

    Science.gov (United States)

    Sizeland, Katie H; Edmonds, Richard L; Basil-Jones, Melissa M; Kirby, Nigel; Hawley, Adrian; Mudie, Stephen; Haverkamp, Richard G

    2015-03-11

    As hides and skins are processed to produce leather, chemical and physical changes take place that affect the strength and other physical properties of the material. The structural basis of these changes at the level of the collagen fibrils is not fully understood and forms the basis of this investigation. Synchrotron-based small-angle X-ray scattering (SAXS) is used to quantify fibril orientation and D-spacing through eight stages of processing from fresh green ovine skins to staked dry crust leather. Both the D-spacing and fibril orientation change with processing. The changes in thickness of the leather during processing affect the fibril orientation index (OI) and account for much of the OI differences between process stages. After thickness is accounted for, the main difference in OI is due to the hydration state of the material, with dry materials being less oriented than wet. Similarly significant differences in D-spacing are found at different process stages. These are due also to the moisture content, with dry samples having a smaller D-spacing. This understanding is useful for relating structural changes that occur during different stages of processing to the development of the final physical characteristics of leather.

  1. Age Differences in Interhemispheric Interactions: Callosal Structure, Physiological Function, and Behavior

    Directory of Open Access Journals (Sweden)

    Brett W Fling

    2011-03-01

    Full Text Available There is a fundamental gap in understanding how brain structural and functional network connectivity are interrelated, how they change with age, and how such changes contribute to older adults’ sensorimotor deficits. Recent neuroimaging approaches including resting state functional connectivity MRI (fcMRI and diffusion tensor imaging (DTI have been used to assess brain functional (fcMRI and structural (DTI network connectivity, allowing for more integrative assessments of distributed neural systems than in the past. Declines in corpus callosum size and microstructure with advancing age have been well documented, but their contributions to age deficits in unimanual and bimanual function are not well defined. Our recent work implicates age-related declines in callosal size and integrity as a key contributor to unimanual and bimanual control deficits. Moreover, our data provide evidence for a fundamental shift in the balance of excitatory and inhibitory interhemispheric processes that occurs with age, resulting in age differences in the relationship between functional and structural network connectivity. Training studies suggest that the balance of interhemispheric interactions can be shifted with experience, making this a viable target for future interventions.

  2. [Structure of the articular cartilage in the middle aged].

    Science.gov (United States)

    Kop'eva, T N; Mul'diiarov, P Ia; Bel'skaia, O B; Pastel', V B

    1983-10-01

    In persons 17-83 years of age having no articular disorders 39 samples of the patellar articular cartilage, the articulated surface and the femoral head have been studied histochemically, histometrically and electron microscopically. Age involution of the articular cartilage is revealed after 40 years of age as a progressive decrease in chondrocytes density in the superficial and (to a less degree) in the intermediate zones. This is accompanied with a decreasing number of 3- and 4-cellular lacunae and with an increasing number of unicellular and hollow lacunae. In some chondrocytes certain distrophic and necrotic changes are revealed. In the articular matrix the zone with the minimal content of glycosaminoglycans becomes thicker and keratansulfate content in the territorial matrix of the cartilage deep zone grows large.

  3. Ageing management of french NPP civil work structures

    Directory of Open Access Journals (Sweden)

    Dauffer D.

    2011-04-01

    Full Text Available This paper presents EDF practice about concrete structure ageing management, from the mechanisms analysis to the formal procedure which allows the French company to increase 900 MWe NPP lifetime until 40 years; it will also introduce its action plan for 60 years lifetime extension. This practice is based on a methodology which identifies every ageing mechanism; both plants feedback and state of the art are screened and conclusions are drawn up into an “ageing analysis data sheet”. That leads at first to a collection of 57 data sheets which give the mechanism identification, the components that are concerned and an analysis grid which is designed to assess the safety risk. This analysis screens the reference documents describing the mechanism, the design lifetime hypotheses, the associated regulation or codification, the feedback experiences, the accessibility, the maintenance actions, the repair possibility and so one. This analysis has to lead to a conclusion about the risk taking into account monitoring and maintenance. If the data sheet conclusion is not clear enough, then a more detailed report is launched. The technical document which is needed, is a formal detailed report which summarizes every theoretical knowledge and monitoring data: its objective is to propose a solution for ageing management: this solution can include more inspections or specific research development, or additional maintenance. After a first stage on the 900 MWe units, only two generic ageing management detailed reports have been needed for the civil engineering part: one about reactor building containment, and one about other structures which focuses on concrete inflating reactions. The second stage consists on deriving this generic analysis (ageing mechanism and detailed reports to every plant where a complete ageing report is required (one report for all equipments and structures of the plant, but specific for each reactor. This ageing management is a

  4. Structural Changes of Malt Proteins During Boiling

    Directory of Open Access Journals (Sweden)

    2009-03-01

    Full Text Available Changes in the physicochemical properties and structure of proteins derived from two malt varieties (Baudin and Guangmai during wort boiling were investigated by differential scanning calorimetry, SDS-PAGE, two-dimensional electrophoresis, gel filtration chromatography and circular dichroism spectroscopy. The results showed that both protein content and amino acid composition changed only slightly during boiling, and that boiling might cause a gradual unfolding of protein structures, as indicated by the decrease in surface hydrophobicity and free sulfhydryl content and enthalpy value, as well as reduced α-helix contents and markedly increased random coil contents. It was also found that major component of both worts was a boiling-resistant protein with a molecular mass of 40 kDa, and that according to the two-dimensional electrophoresis and SE-HPLC analyses, a small amount of soluble aggregates might be formed via hydrophobic interactions. It was thus concluded that changes of protein structure caused by boiling that might influence beer quality are largely independent of malt variety.

  5. Transformation of even-aged European beech (Fagus sylvatica L.) to uneven-aged management under changing growth conditions caused by climate change

    DEFF Research Database (Denmark)

    Schou, Erik; Meilby, Henrik

    2013-01-01

    Transformation from even-aged to uneven-aged forest management is currently taking place throughout Europe. Climate change is, however, expected to change growth conditions—possibly quite radically. Using a deterministic approach, it was the objective of this study to investigate the influence...... of such changes on optimal transformation strategies for an even-aged stand of European Beech in Denmark. For a range of growth change scenarios, represented by changes in site index, optimal harvest policies were determined using a matrix modelling approach and a differential evolution algorithm. Transition...

  6. Age-dependent changes in cat masseter nerve: an electrophysiological and morphological study.

    Science.gov (United States)

    Chase, M H; Engelhardt, J K; Adinolfi, A M; Chirwa, S S

    1992-07-24

    The present study was undertaken to determine the manner in which aging affects the function and structure of the masseter nerve in old cats. Electrophysiological data demonstrated a significant decrease in the conduction velocity of the action potential in old cats compared with that observed in adult cats. Light microscopic analyses revealed an age-dependent decrease in axon diameter. Electron microscopic observations of the masseter nerve in the aged cats revealed a disruption of the myelin sheaths and a pronounced increase in collagen fibers in the endoneurium and perineurium. These morphological changes are discussed and then related to the decrease in conduction velocity which was observed in the electrophysiological portion of this study. PMID:1521161

  7. CHANGES IN VOLATILE COMPOSITION AND SENSORY PROPERTIES OF VUGAVA WINES AGED IN CROATIA OAK BARRELS

    Directory of Open Access Journals (Sweden)

    Stanka HERJAVEC

    2001-09-01

    Full Text Available Vugava musts were fermented in medium-toasted Croatian barrique barrels (225 L made from Quercus petrea and Q. robur oak wood. The oak species used in this research infl uenced the specifi c change of the aroma structure of Vugava wines. During the age period the increase in the concentration of cis and trans oaklactons, guaiacol, eugenol, furfural and 5-methylfurfural was noted. Wines fermented and aged in Q. petrea barrels have higher concentrations of most volatile phenols compared to wines from Q. robur oak wood. From the organoleptic point of view this study suggested that fermentation and on the lees ageing production method in Croatian oak barrels positively infl uenced the quality of Vugava wines where best results were achieved by use of Q. petrea oak wood.

  8. Age structure and disturbance legacy of North American forests

    Directory of Open Access Journals (Sweden)

    Y. Pan

    2011-03-01

    Full Text Available Most forests of the world are recovering from a past disturbance. It is well known that forest disturbances profoundly affect carbon stocks and fluxes in forest ecosystems, yet it has been a great challenge to assess disturbance impacts in estimates of forest carbon budgets. Net sequestration or loss of CO2 by forests after disturbance follows a predictable pattern with forest recovery. Forest age, which is related to time since disturbance, is a useful surrogate variable for analyses of the impact of disturbance on forest carbon. In this study, we compiled the first continental forest age map of North America by combining forest inventory data, historical fire data, optical satellite data and the dataset from NASA's Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS project. A companion map of the standard deviations for age estimates was developed for quantifying uncertainty. We discuss the significance of the disturbance legacy from the past, as represented by current forest age structure in different regions of the US and Canada, by analyzing the causes of disturbances from land management and nature over centuries and at various scales. We also show how such information can be used with inventory data for analyzing carbon management opportunities. By combining geographic information about forest age with estimated C dynamics by forest type, it is possible to conduct a simple but powerful analysis of the net CO2 uptake by forests, and the potential for increasing (or decreasing this rate as a result of direct human intervention in the disturbance/age status. Finally, we describe how the forest age data can be used in large-scale carbon modeling, both for land-based biogeochemistry models and atmosphere-based inversion models, in order to improve the spatial accuracy of carbon cycle simulations.

  9. Outlook for activity and structural change

    International Nuclear Information System (INIS)

    The level of energy-using activities is continuing to increase throughout the world, but the rates of likely growth differ among regions. Over the next 20 years, manufacturing production is expected to grow at a rapid pace in parts of the developing world, and moderately in the OECD countries. In the Former East Bloc, it seems likely to stagnate or decline for much of the 1990s, but could then grow at a moderate pace if the transition to a market economy is successfully managed. Domestic passenger travel seems likely to increase everywhere, and growth in international travel will be especially strong. Freight transport activity is difficult to evaluate in the aggregate, since the composition of goods changes over time, but increase is expected in all regions, especially in the developing countries. Structural change within sectors will have significant impacts on energy use. In manufacturing, faster growth in light industry will lead to lower energy intensity in the OECD countries and especially in the Former East Bloc. The outlook in the LDCs suggests somewhat higher growth in energy-intensive industries, but this trend will vary among countries. In passenger travel, structural change is pointing toward higher energy intensity in most of the world as the role of automobiles and air travel continues to grow. Increase in the use of trucks is pushing in a similar direction in freight transport. In the residential sector, structural change will have only a moderate impact in the OECD countries, where per capita levels of home services are already high, but will push energy use significantly upward in the LDCs, and to a lesser extent, in the Former East Bloc. 17 refs., 4 figs., 1 tab

  10. Health care leadership in an age of change.

    Science.gov (United States)

    Farrell, Maureen

    2003-01-01

    This study examined the leadership practices of a sample of network and hospital administrators in metropolitan Victoria, Australia. It was undertaken in the mid-1990s when the State Liberal-National (Coalition) Government in Victoria established Melbourne's metropolitan health care networks. I argue that leadership, and the process of leading, contributes significantly to the success of the hospital in a time of turmoil and change. The sample was taken from the seven health care networks and consisted of 15 network and hospital administrators. Bolman and Deal's frames of leadership--structural, human resource, political and symbolic--were used as a framework to categorize the leadership practices of the administrators. The findings suggest a preference for the structural frame--an anticipated result, since the hospital environment is more conducive to a style of leadership that emphasizes rationality and objectivity. The human resource frame was the second preferred frame, followed by the political and symbolic. These findings suggest that network and hospital administrators focus more on intellectual than spiritual development, and perhaps this tendency needs to be addressed when educating present and future hospital leaders.

  11. Age Structure of the Otter (Lutra lutra Population in England and Wales, and Problems with Cementum Ageing

    Directory of Open Access Journals (Sweden)

    Eleanor Sherrard-Smith

    2010-01-01

    Full Text Available Age is an important parameter in understanding population structure and age-dependent processes such as accumulation of contaminants. In the current study, canines and incisors of sub-adult and mature wild otters (Lutra lutra from England and Wales were sectioned and incremental cementum lines were used as an indication of age. The age structure of the sample population is much younger than some European populations (of 110 otters aged, only 10 were aged four or older. Cementum ageing is useful here in giving a broad indication of age structure, but is imprecise for species which do not exhibit seasonal breeding. Age is likely to be underestimated in most cases.

  12. A data base for aging of structural materials

    International Nuclear Information System (INIS)

    The U.S. Nuclear Regulatory Commission (USNRC) initiated a Structural Aging (SAG) Program at the Oak Ridge National Laboratory (ORNL). The objective of the program is to provide assistance in identifying potential structural safety issues and to establish acceptance criteria for use in nuclear power plant evaluations for continued service. One of the main parts of the program focuses on the development of a Structural Materials Information Center where long-term and environment-dependent material properties are being collected and assembled into a data base. This data base is presented in two complementary formats. The Structural Materials Handbook is an expandable, hard-copy reference document that contains the complete data base for each material. The Structural Materials Electronic Data Base is accessible using an IBM-compatible personal computer. This paper presents an overview of the Structural Materials Information Center and briefly describes the features of the handbook and the electronic data base. In addition, a proposed method for using the data base to establish current property values for materials in existing concrete structures and to estimate the future performance of these materials is also presented. (author)

  13. A data base for aging of structural materials

    International Nuclear Information System (INIS)

    USNRC initiated a Structural Aging (SAG) Program ORNL. The objective of the program is to provide assistance in identifying potential structural safety issues and to establish acceptance criteria for use in nuclear power plant evaluations for continued service. One main part focuses on the development of a Structural Materials Information Center where long-term and environment-dependent material properties are being collected and assembled into a data base. This data base is presented in two complementary formats. The Structural Materials Handbook is an expandable, hard-copy reference document that contains the complete data base for each material. The Structural Materials Electronic Data Base is accessible using an IBM-compatible personal computer. This paper presents an overview of the Structural Materials Information Center and briefly describes the features of the handbook and the electronic data base. In addition, a proposed method for using the data base to establish current property values for materials in existing concrete structures and to estimate the future performance of these materials is also presented

  14. Degenerative and age-related changes in the x-irradiated kidney of the rat

    International Nuclear Information System (INIS)

    Exposure of rat kidney to a single dose of radiation (4000 rad) produced degenerative changes and accumulation of fluorescent granules after a latent period of approximately 8 weeks. The appearance of these fluorescent granules corresponded to the development of structural damage to the kidney. Radiation produced relatively minor changes in the lipid content of the kidney. The level of cholesteryl esters was increased, arachidonic acid content was decreased, and there was a progressive increase in fluorescent substances related to aging, as detected by thin layer chromatography, in chloroform-methanol extracts of the irradiated kidney. However, there was no apparent loss of vitamin E or ubiquinone and no increase in TBA values or diene conjugation as might be expected as effects of lipid oxidation. These changes were evident by the second month following irradiation and corresponded to the development of the morphological changes. The presence of lipofuscin substances, reduced arachidonic acid, and an increase in cholesteryl esters indicated an acceleration of aging in the radiation-exposed kidney. The relationship of lipid oxidation to the acceleration of aging and the production of acute renal lesions was not apparent

  15. Muscle mitochondrial changes with aging and exercise1234

    OpenAIRE

    Lanza, Ian R.; Nair, K. Sreekumaran

    2008-01-01

    Aging has been reported to be accompanied by reduced mitochondrial function and insulin sensitivity. Whether these deleterious effects result from chronological age or lifestyle-related factors such as adiposity and physical inactivity remains debatable. The beneficial effects of exercise on mitochondrial function and insulin sensitivity are well documented; however, it is unclear whether exercise can effectively prevent, reverse, or delay the onset of these age-related dysfunctions. Other in...

  16. Age-related changes in antral endocrine cells in mice

    OpenAIRE

    Sandstrom, O.; Mahdavi, J.; El-Salhy, M.

    1999-01-01

    Antral endocrine cells in four age groups of mice, namely prepubertal (1 month old), young (3 months old), ageing (12 months old) and senescent (24 months old), were detected by immunocytochemistry and quantified by computerized image analysis. A statistical difference was detected between the different age groups regarding the numbers of gastrin-, somatostatin-, and serotonin-immunoreactive cells. The number of gastrin-immunoreactive cells significantly increa...

  17. Radiation-induced structural changes. 4

    International Nuclear Information System (INIS)

    This seminar was held for discussion on recent progress in experimental investigation of positron and its application to material science. Fundamental characteristics of positronium, measuring method, molecular structure of positronium, and its annihilation and reaction, in liquid phase positronium chemistry are reported. The nonthermal positrons (0.25-2.5 keV) are occurred in KURRI-LINAC, slow positrons are found out by moderating with solid xenon film. Positronium formation in insulating materials are reported. Positron lifetime and insulating rupture strength are measured with epoxy resin and fluororesin changing bridging density, experimental materials temperature, gamma ray dose Free-volume studies on polymer in multiphase systems are evaluated using the method of spin labeling, the molecular dynamics of polymer chains are discussed. The anisotropy diffusion process on structural relaxation of linear polymers are described, introducing the molecular dynamics simulation of polarization and stress relaxation of ferroelectric polymers. (J.P.N.)

  18. Stromatolite laminae (Lagoa Vermelha, Brasil) as archives for reservoir age changes

    Science.gov (United States)

    Bruggmann, Sylvie; Vasconcelos, Crisogono; Hajdas, Irka

    2016-04-01

    As laminated biogenic or abiogenic sedimentary structures [1], stromatolites record environmental changes along growth profiles, revealing possible changes in reservoir ages due to input of older carbon. A modern stromatolite sample was collected in Lagoa Vermelha (100 km east of Rio de Janeiro, Brasil) an area known for upwelling of South Atlantic Central Water (SACW). 34 samples from a transect cutting the lamination were collected with a hand-driller for standard geochemistry and 14C AMS analyses. Shells collected in 2015 were analysed for estimation of the present-day reservoir age. 14C ages of laminae and the reservoir age were used to apply the age-depth model to the stromatolite transect with the OxCal depositional model (Marine13 calibration curve; [2]). Small-scale changes in the composition of laminae report environmental changes, e.g. upwelling. The well-laminated middle part (laminated boundstone; ca. 4cm) of the stromatolite transect was found to have grown in a short time period of less than 100 years (1163-1210 14C y BP), with four excursions towards older 14C ages (ca. 1200 14C y BP). To detect possible changes of marine 14C, calendar years assuming a stable modern reservoir age were used to simulate atmospheric 14C ages with the southern hemisphere IntCal13 atmospheric calibration curve [3]. The offset between the measured and simulated 14C ages indicates a variability of the reservoir age between -99 and 268 14C y with highest reservoir correction found for the layers with indication of environmental changes (e.g. upwelling). Thus, this simulation confirms the occurrence of older carbon and points out the sensitivity of stromatolites for changing reservoir ages. [1] M.A. Semikhatov, C.D. Gebelein, P. Cloud, S.M. Awramik, W.C. Benmore (1979). Stromatolite morphogenesis - progress and problems. Canadian Journal of Earth Sciences, 19:992-1015. [2] P.J. Reimer, E. Bard, A. Bayliss, J. W. Beck, P. G. Blackwell, C. Bronk Ramsey, C. E. Buck, H. Cheng, R

  19. Ages of celiac disease: From changing environment to improved diagnostics

    Institute of Scientific and Technical Information of China (English)

    Alberto Tommasini; Tarcisio Not; Alessandro Ventura

    2011-01-01

    From the time of Gee's landmark writings, the recent history of celiac disease (CD) can be divided into manyages, each driven by a diagnostic advance and a deeperknowledge of disease pathogenesis. At the same time,these advances were paralleled by the identification of new clinical patterns associated with CD and by a continuous redefinition of the prevalence of the diseasein population. In the beginning, CD was considered a chronic indigestion, even if the causative food was notknown; later, the disease was proven to depend on anintolerance to wheat gliadin, leading to typical mucosalchanges in the gut and to a malabsorption syndrome. This knowledge led to curing the disease with a gluten-free diet. After the identification of antibodies to gluten(AGA) in the serum of patients and the identification of gluten-specific lymphocytes in the mucosa, CD was described as an immune disorder, resembling a chronic "gluten infection". The use of serological testing for AGA allowed identification of the higher prevalence of this disorder, revealing atypical patterns of presenta-tion. More recently, the characterization of autoantibod-ies to endomysium and to transglutaminase shifted the attention to a complex autoimmune pathogenesis and to the increased risk of developing autoimmune disor-ders in untreated CD. New diagnostic assays, based on molecular technologies, will introduce new changes, with the promise of better defining the spectrum of gluten reactivity and the real burden of gluten related-disorders in the population. Herein, we describe the different periods of CD experience, and further devel-opments for the next celiac age will be proposed.

  20. Age-Related Degenerative Functional, Radiographic, and Histological Changes of the Shoulder in Non-Human Primates

    Science.gov (United States)

    Plate, Johannes F.; Bates, Christopher M.; Mannava, Sandeep; Smith, Thomas L.; Jorgensen, Matthew J.; Register, Thomas C.; Stehle, John R.; High, Kevin P.; Shively, Carol A.; Kaplan, Jay R.; Saul, Katherine R.; Tuohy, Christopher J.

    2013-01-01

    Background Non-human primates have similar shoulder anatomy and physiology compared to humans and may represent a previously underutilized model for shoulder research. This study sought to identify naturally occurring bony and muscular degeneration in the shoulder of non-human primates and to assess relationships between structural and functional aspects of the shoulder and measures of physical function of the animals. We hypothesized that age-related degenerative changes in the shoulders of non-human primates would resemble those observed in aging humans. Methods Middle-aged (n=5, ages 9.4 to 11.8 years) and elderly (n=6, ages 19.8 to 26.4 years) female vervet monkeys were studied for changes in mobility and shoulder function, and radiographic and histologic signs of age-related degeneration. Results Four out of six (4/6) elderly animals had degenerative changes of the glenoid compared to 0/5 of the middle-aged animals (p=0.005). Elderly animals had glenoid retroversion, decreased joint space, walked slower and spent less time climbing and hanging than middle-aged vervets (protator cuff tears were not observed in any of the eleven animals. Discussion and Conclusion The vervet monkey naturally undergoes age-related functional, radiographic and histological changes of the shoulder and may qualify as an animal model for selected translational research of shoulder osteoarthritis. Level of evidence Basic Science Study, in-vivo Animal Model PMID:23352182

  1. Perceived Changes in Well-Being: The Role of Chronological Age, Target Age, and Type of Measure

    Science.gov (United States)

    Okun, Morris A.; Dittburner, Julie L.; Huff, Barbara P.

    2006-01-01

    The goal of this study is to investigate whether perceived changes in one's well-being from the present to the future are related to chronological age, target age, and type of measure (psychological well-being versus life satisfaction). Young adults (N = 114) rated their current well-being and their future well-being at one of three target ages…

  2. Change of the Microstructure of ZnO Arrester Block by Lightning Surge Current and Ageing Test

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Bok Hee; Kang, Sung Man [Inha University (Korea)

    2000-07-01

    This paper deals with the change of the micro-structure of ZnO associated with lightning surge current and ageing test. In this work, a surge current generator which can produce 8/20 [{mu}s],6 [kA] impulse current is designed and fabricated to simulate the lightning impulse current. The residual voltage and leakage current flowing to ZnO blocks are observed. Also a compensation circuit was used in resistive current measurement. The micro-structures of ZnO arrester block were significantly changed by lightning surge current and accelerated temperature ageing test. (author). 6 refs., 7 figs., 1 tab.

  3. Lumbar spinal mobility changes among adults with advancing age

    Directory of Open Access Journals (Sweden)

    Ismaila Adamu Saidu

    2011-01-01

    Conclusion : Using these data, we developed normative values of spinal mobility for each sex and age group. This study helps the clinicians to understand and correlate the restrictions of lumbar spinal mobility due to age and differentiate the limitations due to disease.

  4. Precise age estimation from different ageing structures in the striped snakehead, Channa striata (Bloch,1793, collected from the river Ganga

    Directory of Open Access Journals (Sweden)

    Salman Khan

    2015-11-01

    Full Text Available In Channa striata (N=156; TL=17-60cm sampled from the river Ganga, the annuli laid on different ageing structures such as otoliths (whole and sectioned, scales, opercular bone and vertebrae were observed for age estimation. Standard procedures were followed to prepare and study the age structures. Age estimates obtained from different hard structures were analysed to calculate the parameters for precise age estimation viz., APE, CV and PA. The sectioned otoliths showed the highest (89.9% percentage of agreement between readers while least average percent error (1.20% and coefficient of variation (3.81% values between two readers. Thus sectioned otoliths were considered to be the most suitable method for estimating age in C. striata. When sectioned otoliths were compared with other bony structures, the highest percent agreement and lowest average percent error and coefficient of variation values were found between sectioned otoliths and whole otoliths age estimates.

  5. The effects of migration and fertility on the age-sex structure of Lagos State, Nigeria

    Directory of Open Access Journals (Sweden)

    Esther Ugomma EJEKWUMADU

    2009-12-01

    Full Text Available This research was carried out to appraise the influence of fertility and migration on the age-sex population structure of Lagos State, Nigeria. Respondents were randomly selected and given questionnaire to fill with regards to fertility and migration trends in the study area. Using partial correlation and multiple regression analyses, we determined the influence of migration and fertility on the age structure of the population. The combined effects of the partial correlation of fertility and migration were 0.66 (males and 0.79 (females. The regression analyses yielded influence of fertility of 9.6 and 11.7 for males and females respectively, which far outstrips the influence of migration of 6.4 and 1.5 for males and females respectively on the age-sex structure. Also, the base constant was –5.1 for females and –3.2 for males i.e. the minimum change in age of male and female populations that would occur before the influence of fertility and migration become noticeable. Finally, the socio-economic implications of the age-sex structure were highlighted.

  6. Age-related changes in mucins from human whole saliva.

    Science.gov (United States)

    Denny, P C; Denny, P A; Klauser, D K; Hong, S H; Navazesh, M; Tabak, L A

    1991-10-01

    The predominant mucins in human whole saliva, MG1 and MG2, serve to protect and to lubricate the oral cavity. In this study, both unstimulated and stimulated whole salivas were collected from two groups of subjects: young (18-35 years of age) and aged (65-83 years of age). The subjects were in apparent good health. Saliva samples from each subject were analyzed by SDS-PAGE. The gels were stained with Stains-all, and both MG1 and MG2 were quantitated by video-image densitometry. The protocol gave reproducible values for each mucin. The stimulated and unstimulated salivas from aged subjects showed significant reductions in concentrations of both MG1 and MG2, as quantitated in mucin dye-binding units. Possible associations of these reductions with the aging process are discussed.

  7. Age-Associated Lipidome Changes in Metaphase II Mouse Oocytes.

    Directory of Open Access Journals (Sweden)

    Hyuck Jun Mok

    Full Text Available The quality of mammalian oocytes declines with age, which negatively affects fertilization and developmental potential. The aging process often accompanies damages to macromolecules such as proteins, DNA, and lipids. To investigate if aged oocytes display an altered lipidome compared to young oocytes, we performed a global lipidomic analysis between oocytes from 4-week-old and 42 to 50-week-old mice. Increased oxidative stress is often considered as one of the main causes of cellular aging. Thus, we set up a group of 4-week-old oocytes treated with hydrogen peroxide (H2O2, a commonly used oxidative stressor, to compare if similar lipid species are altered between aged and oxidative-stressed oocytes. Between young and aged oocytes, we identified 26 decreased and 6 increased lipids in aged oocytes; and between young and H2O2-treated oocytes, we identified 35 decreased and 26 increased lipids in H2O2-treated oocytes. The decreased lipid species in these two comparisons were overlapped, whereas the increased lipid species were distinct. Multiple phospholipid classes, phosphatidic acid (PA, phosphatidylinositol (PI, phosphatidylserine (PS, and lysophosphatidylserine (LPS significantly decreased both in H2O2-treated and aged oocytes, suggesting that the integrity of plasma membrane is similarly affected under these conditions. In contrast, a dramatic increase in diacylglycerol (DG was only noted in H2O2-treated oocytes, indicating that the acute effect of H2O2-caused oxidative stress is distinct from aging-associated lipidome alteration. In H2O2-treated oocytes, the expression of lysophosphatidylcholine acyltransferase 1 increased along with increases in phosphatidylcholine. Overall, our data reveal that several classes of phospholipids are affected in aged oocytes, suggesting that the integrity of plasma membrane is associated with maintaining fertilization and developmental potential of mouse oocytes.

  8. Structural changes in dairy business in Croatia

    Directory of Open Access Journals (Sweden)

    Teo Vujčić

    2005-01-01

    Full Text Available Croatia today is in the economy transition process that also includes agriculture aiming to increase production and achieving competitive standard with international and European markets. Currently, domestic cow milk production ensures 80% of annual milk and dairy products requirements with the 20% import. In the period from 1990-1992, during the patriot war, 103000 cows and heifers were destroyed. Since then, Croatia started the gradual process of reorganization of the agricultural private sector including dairy business in order to increase production insensitivity.The agricultural structure of dairy segment is unsatisfactory with only 23.39% of farms holding four or more heifers. Households with 3 cows per farm dominate with average real estate of 0.10-3.0 acres.Changes in milk production (1990-2003 are reflected in the decrease of the number of breeding cattle – index 56.13%, and decrease of milk market producers from 65 000 to 65 151. Never the less, positive trends towards stabilization in milk production (2003 – 642 mil litres and annual milk intake increased from 342 mil litres in 1990 to 472 mil litres in 2003 (index 138.08% can be noticed. Changes in the structure of milk producers show certain positive movements as 23.39% of producers have 53.40% cows and respectively participation in milk production and buy off. Until 2008, with determined development conditions, cow milk production can increase for 42% and from 2703 litres to average of 4000 litres per dairy cow.

  9. Age-Dependent Changes in Geometry, Tissue Composition and Mechanical Properties of Fetal to Adult Cryopreserved Human Heart Valves.

    Science.gov (United States)

    van Geemen, Daphne; Soares, Ana L F; Oomen, Pim J A; Driessen-Mol, Anita; Janssen-van den Broek, Marloes W J T; van den Bogaerdt, Antoon J; Bogers, Ad J J C; Goumans, Marie-José T H; Baaijens, Frank P T; Bouten, Carlijn V C

    2016-01-01

    There is limited information about age-specific structural and functional properties of human heart valves, while this information is key to the development and evaluation of living valve replacements for pediatric and adolescent patients. Here, we present an extended data set of structure-function properties of cryopreserved human pulmonary and aortic heart valves, providing age-specific information for living valve replacements. Tissue composition, morphology, mechanical properties, and maturation of leaflets from 16 pairs of structurally unaffected aortic and pulmonary valves of human donors (fetal-53 years) were analyzed. Interestingly, no major differences were observed between the aortic and pulmonary valves. Valve annulus and leaflet dimensions increase throughout life. The typical three-layered leaflet structure is present before birth, but becomes more distinct with age. After birth, cell numbers decrease rapidly, while remaining cells obtain a quiescent phenotype and reside in the ventricularis and spongiosa. With age and maturation-but more pronounced in aortic valves-the matrix shows an increasing amount of collagen and collagen cross-links and a reduction in glycosaminoglycans. These matrix changes correlate with increasing leaflet stiffness with age. Our data provide a new and comprehensive overview of the changes of structure-function properties of fetal to adult human semilunar heart valves that can be used to evaluate and optimize future therapies, such as tissue engineering of heart valves. Changing hemodynamic conditions with age can explain initial changes in matrix composition and consequent mechanical properties, but cannot explain the ongoing changes in valve dimensions and matrix composition at older age.

  10. The Aging of the Global Population: The Changing Epidemiology of Disease and Spinal Disorders.

    Science.gov (United States)

    Fehlings, Michael G; Tetreault, Lindsay; Nater, Anick; Choma, Ted; Harrop, James; Mroz, Tom; Santaguida, Carlo; Smith, Justin S

    2015-10-01

    The global population is currently undergoing an upward shift in its age structure due to decreasing fertility rates and increasing life expectancy. As a result, clinicians worldwide will be required to manage an increasing number of spinal disorders specific to the elderly and the aging of the spine. Elderly individuals pose unique challenges to health care systems and to spinal physicians as these patients typically have an increased number of medical comorbidities, reduced bone density mass, more severe spinal degeneration and a greater propensity to falls. In anticipation of the aging of the population, we undertook this project to heighten physicians' awareness of age-related spinal disorders, including geriatric odontoid fractures, central cord syndrome, osteoporotic compression fractures, degenerative cervical myelopathy, lumbar spinal stenosis and degenerative spinal deformity. This introductory article provides an overview of the changing demographics of the global population; discusses the age-related alterations that may occur to the spine; and summarizes the purpose and contents of this focus issue. PMID:26378347

  11. [Age-related changes in the rat lacrimal gland: specific morphology and unknown nature].

    Science.gov (United States)

    Gancharova, O S; Manskikh, V N

    2014-01-01

    The rat lacrimal apparatus includes several glands; among them, the exorbital gland plays the central role. Its parenchyma and stroma undergo prominent morphologic changes with age. The parenchymal transformation includes metaplasia of some of its acini and their turning into Harderian gland-like structures (harderization), accumulation of gland ducts ("ductularization"), and morphologic dysplasia-cytomegaly, karyomegaly, and'cell and nuclearpolymorphism in the other part of acini. All these transformations are hormone-dependent andsex-specific: theyoften appear in males. On the final stages of age-related transformations, the lacrimal gland tissue is morphologically similar to the neoplasm and has neoplastic morphology but no other features of a tumor. Therefore, the rat lacrimal gland is an interesting object to study tissue and cell atypia. In the rat glandular stroma, lymphocytic infiltration and fibrosis appear with age; these changes are similar to processes taking place in human lacrimal apparatus involved in the pathogenesis of senile dry eye syndrome. The spontaneous changes in the rat lacrimal gland, predominantly in male rats, can be used as a model of the human lacrimal apparatus disorders.

  12. Genome-wide age-related changes in DNA methylation and gene expression in human PBMCs

    NARCIS (Netherlands)

    Steegenga, W.T.; Boekschoten, M.V.; Lute, C.; Hooiveld, G.J.E.J.; Groot, de P.J.; Morris, T.J.; Teschendorff, A.E.; Butcher, L.M.; Beck, S.; Müller, M.R.

    2014-01-01

    Aging is a progressive process that results in the accumulation of intra- and extracellular alterations that in turn contribute to a reduction in health. Age-related changes in DNA methylation have been reported before and may be responsible for aging-induced changes in gene expression, although a c

  13. Structural Integrity Analysis of CEA Change Platform

    International Nuclear Information System (INIS)

    The Control Element Assembly Change Platform (CEA CP) is similar to a gantry crane. The CEA CP for Shin-Kori units 3 and 4 (SKN 3 and 4) consists of a bridge, which spans the reactor cavity pool and a gantry superstructure mounted on the bridge. The structure is approximately 8.8 m wide, 4.9 m long and 10.6 m high. The gantry superstructure supports one ton capacity hoist trolley and the bridge supports the In Core Instrumentation (ICI) retrieval cart which moves along the bridge. This paper presents the dynamic and structural analysis of CEA CP which is greater than that of the previous nuclear power plants to verify the structural integrity under the application of the earthquake spectrum. The analysis have been performed using the three orthogonal SSE response spectrum for SKN 3 and 4 which shows much higher acceleration value than OPR- 1000 Plants. In addition, the analyses are performed by 3-dimensional finite element analysis using ANSYS software

  14. Age structure and disturbance legacy of North American forests

    Directory of Open Access Journals (Sweden)

    Y. Pan

    2010-02-01

    Full Text Available Most forests of the world are recovering from a past disturbance. It is well known that forest disturbances profoundly affect carbon stock and fluxes in forest ecosystems, yet it has been a great challenge to assess disturbance impacts in estimates of forest carbon budgets. Net sequestration or loss of CO2 by forests after disturbance follows a predictable pattern with forest recovery. Forest age, which is related to time since disturbance, is the most available surrogate variable for various forest carbon analyses that concern the impact of disturbance. In this study, we compiled the first continental forest age map of North America by combining forest inventory data, historical fire data, optical satellite data and the dataset from NASA's LEDAPS project. Mexico and interior Alaska are excluded from this initial map due to unavailability of all required data sets, but work is underway to develop some different methodology for these areas. We discuss the significance of disturbance legacy from the past, as represented by current forest age structure in different regions of the US and Canada, tracking back disturbances caused by human and nature over centuries and at various scales. We also show how such information can be used with inventory data for analyzing carbon management opportunities, and other modeling applications. By combining geographic information about forest age with estimated C dynamics by forest type, it is possible to conduct a simple but powerful analysis of the net CO2 uptake by forests, and the potential for increasing (or decreasing this rate as a result of direct human intervention in the disturbance/age status. The forest age map may also help address the recent concern that the terrestrial C sink from forest regrowth in North America may saturate in the next few decades. Finally, we describe how the forest age data can be used in large-scale carbon modeling, both for land-based biogeochemistry

  15. Age-related changes in ultra-triathlon performances

    OpenAIRE

    Knechtle, Beat; Rüst, Christoph,; Knechtle, Patrizia; Rosemann, Thomas; Lepers, Romuald

    2012-01-01

    International audience BackgroundThe age-related decline in performance has been investigated in swimmers, runners and triathletes. No study has investigated the age-related performance decline in ultra-triathletes. The purpose of this study was to analyse the age-related declines in swimming, cycling, running and overall race time for both Triple Iron ultra-triathlon (11.4-km swimming, 540-km cycling and 126.6-km running) and Deca Iron ultra-triathlon (38-km swimming, 1,800-km cycling and...

  16. Age-related changes in the kinetics of human lenses: prevention of the cataract

    Science.gov (United States)

    Pescosolido, Nicola; Barbato, Andrea; Giannotti, Rossella; Komaiha, Chiara; Lenarduzzi, Fiammetta

    2016-01-01

    The crystalline lens is a transparent, biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina and, by changing shape, it adjusts focal distance (accommodation). The three classes of structural proteins found in the lens are α, β, and γ crystallins. These proteins make up more than 90% of the total dry mass of the eye lens. Other components which can be found are sugars, lipids, water, several antioxidants and low weight molecules. When ageing changes occur in the lens, it causes a gradual reduction in transparency, presbyopia and an increase in the scattering and aberration of light waves as well as a degradation of the optical quality of the eye. The main changes that occur with aging are: 1) reduced diffusion of water from the outside to the inside of the lens and from its cortical to its nuclear zone; 2) crystalline change due to the accumulation of high molecular weight aggregates and insoluble proteins; 3) production of advanced glycation end products (AGEs), lipid accumulation, reduction of reduced glutathione content and destruction of ascorbic acid. Even if effective strategies in preventing cataract onset are not already known, good results have been reached in some cases with oral administration of antioxidant substances such as caffeine, pyruvic acid, epigallocatechin gallate (EGCG), α-lipoic acid and ascorbic acid. Furthermore, methionine sulfoxide reductase A (MSRA) over expression could protect lens cells both in presence and in absence of oxidative stress-induced damage. Nevertheless, promising results have been obtained by reducing ultraviolet-induced oxidative damage.

  17. Early-age volume changes of extrudable reactive powder concrete

    OpenAIRE

    De Noirfontaine M.N.; Mounanga P.; Khelidj A.; Dunstetter F.; Cherkaoui K.; Courtial M.

    2010-01-01

    This article presents a study on the early-age autogenous deformations of Extrudable Reactive Powder Concretes (ERPCs), especially designed for the making of concrete pipes by extrusion. Different ERPC mixtures, with variable amounts of polycarboxylate superplasticizer (SP), have been investigated. Results on 28-day mechanical properties, early-age hydration rate, autogenous shrinkage and premature cracking risk are analyzed and discussed in relation with the ERPC mix parameters.

  18. Early-age volume changes of extrudable reactive powder concrete

    Directory of Open Access Journals (Sweden)

    De Noirfontaine M.N.

    2010-06-01

    Full Text Available This article presents a study on the early-age autogenous deformations of Extrudable Reactive Powder Concretes (ERPCs, especially designed for the making of concrete pipes by extrusion. Different ERPC mixtures, with variable amounts of polycarboxylate superplasticizer (SP, have been investigated. Results on 28-day mechanical properties, early-age hydration rate, autogenous shrinkage and premature cracking risk are analyzed and discussed in relation with the ERPC mix parameters.

  19. Early-age volume changes of extrudable reactive powder concrete

    Science.gov (United States)

    Cherkaoui, K.; Courtial, M.; Dunstetter, F.; Khelidj, A.; Mounanga, P.; de Noirfontaine, M. N.

    2010-06-01

    This article presents a study on the early-age autogenous deformations of Extrudable Reactive Powder Concretes (ERPCs), especially designed for the making of concrete pipes by extrusion. Different ERPC mixtures, with variable amounts of polycarboxylate superplasticizer (SP), have been investigated. Results on 28-day mechanical properties, early-age hydration rate, autogenous shrinkage and premature cracking risk are analyzed and discussed in relation with the ERPC mix parameters.

  20. Climate change-associated trends in net biomass change are age dependent in western boreal forests of Canada.

    Science.gov (United States)

    Chen, Han Y H; Luo, Yong; Reich, Peter B; Searle, Eric B; Biswas, Shekhar R

    2016-09-01

    The impacts of climate change on forest net biomass change are poorly understood but critical for predicting forest's contribution to the global carbon cycle. Recent studies show climate change-associated net biomass declines in mature forest plots. The representativeness of these plots for regional forests, however, remains uncertain because we lack an assessment of whether climate change impacts differ with forest age. Using data from plots of varying ages from 17 to 210 years, monitored from 1958 to 2011 in western Canada, we found that climate change has little effect on net biomass change in forests ≤ 40 years of age due to increased growth offsetting increased mortality, but has led to large decreases in older forests due to increased mortality accompanying little growth gain. Our analysis highlights the need to incorporate forest age profiles in examining past and projecting future forest responses to climate change.

  1. Climate change-associated trends in net biomass change are age dependent in western boreal forests of Canada.

    Science.gov (United States)

    Chen, Han Y H; Luo, Yong; Reich, Peter B; Searle, Eric B; Biswas, Shekhar R

    2016-09-01

    The impacts of climate change on forest net biomass change are poorly understood but critical for predicting forest's contribution to the global carbon cycle. Recent studies show climate change-associated net biomass declines in mature forest plots. The representativeness of these plots for regional forests, however, remains uncertain because we lack an assessment of whether climate change impacts differ with forest age. Using data from plots of varying ages from 17 to 210 years, monitored from 1958 to 2011 in western Canada, we found that climate change has little effect on net biomass change in forests ≤ 40 years of age due to increased growth offsetting increased mortality, but has led to large decreases in older forests due to increased mortality accompanying little growth gain. Our analysis highlights the need to incorporate forest age profiles in examining past and projecting future forest responses to climate change. PMID:27465040

  2. Aging related changes in determinants of muscle force generating capacity: a comparison of muscle aging in men and male rodents.

    Science.gov (United States)

    Ballak, Sam B; Degens, Hans; de Haan, Arnold; Jaspers, Richard T

    2014-03-01

    Human aging is associated with a progressive decline in skeletal muscle mass and force generating capacity, however the exact mechanisms underlying these changes are not fully understood. Rodents models have often been used to enhance our understanding of mechanisms of age-related changes in human skeletal muscle. However, to what extent age-related alterations in determinants of muscle force generating capacity observed in rodents resemble those in humans has not been considered thoroughly. This review compares the effect of aging on muscle force generating determinants (muscle mass, fiber size, fiber number, fiber type distribution and muscle specific tension), in men and male rodents at similar relative age. It appears that muscle aging in male F344*BN rat resembles that in men most; 32-35-month-old rats exhibit similar signs of muscle weakness to those of 70-80-yr-old men, and the decline in 36-38-month-old rats is similar to that in men aged over 80 yrs. For male C57BL/6 mice, age-related decline in muscle force generating capacity seems to occur only at higher relative age than in men. We conclude that the effects on determinants of muscle force differ between species as well as within species, but qualitatively show the same pattern as that observed in men.

  3. Effects of age on spatial information processing: relationship to senescent changes in brain noradrenergic and opioid systems

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, P.R.

    1985-01-01

    A major focus in current research on aging is the identification of senescent changes in cognitive function in laboratory animals. This literature indicates that the processing of spatial information may be particularly impaired during senescence. The degree to which nonspecific factors (eg. sensory of motor deficits) contribute to behavioral impairments in aging, however, remains largely uninvestigated. In addition, few studies have attempted to identify senescent changes in brain structure and function which might underlie the behavioral manifestations of aging. In the behavioral experiments reported here, the authors tested young, middle-age, and senescent rates in several versions of a spatial memory task, the Morris water maze. The results of these investigations demonstrate that aged rats are significantly impaired in the Morris task compared to young or middle-age animals. In addition, these studies indicate that age-related deficits in the water maze reflect a specific dysfunction in the ability of older animals to effectively process spatial information rather than a senescent decline in sensory or motor functions. Using the subjects from the behavioral studies, additional investigations assessed whether age-dependent changes in neurochemical and neuroanatomical systems which are known to mediate spatial learning in young animals were related to the behavioral deficits exhibited by aged rats. The results of these studies demonstrate that a portion of senescent animals exhibit significant increases in lateral septal /sup 3/H-desmethylimipramine binding and decrease in /sup 3/H-naloxone binding in this same region as assessed by quantitative in vitro autoradiography.

  4. Effect of Population Structure Change on Carbon Emission in China

    Directory of Open Access Journals (Sweden)

    Wen Guo

    2016-03-01

    Full Text Available This paper expanded the Logarithmic Mean Divisia Index (LMDI model through the introduction of urbanization, residents’ consumption, and other factors, and decomposed carbon emission changes in China into carbon emission factor effect, energy intensity effect, consumption inhibitory factor effect, urbanization effect, residents’ consumption effect, and population scale effect, and then explored contribution rates and action mechanisms of the above six factors on change in carbon emissions in China. Then, the effect of population structure change on carbon emission was analyzed by taking 2003–2012 as a sample period, and combining this with the panel data of 30 provinces in China. Results showed that in 2003–2012, total carbon emission increased by 4.2117 billion tons in China. The consumption inhibitory factor effect, urbanization effect, residents’ consumption effect, and population scale effect promoted the increase in carbon emissions, and their contribution ratios were 27.44%, 12.700%, 74.96%, and 5.90%, respectively. However, the influence of carbon emission factor effect (−2.54% and energy intensity effect (−18.46% on carbon emissions were negative. Population urbanization has become the main population factor which affects carbon emission in China. The “Eastern aggregation” phenomenon caused the population scale effect in the eastern area to be significantly higher than in the central and western regions, but the contribution rate of its energy intensity effect (−11.10 million tons was significantly smaller than in the central (−21.61 million tons and western regions (−13.29 million tons, and the carbon emission factor effect in the central area (−3.33 million tons was significantly higher than that in the eastern (−2.00 million tons and western regions (−1.08 million tons. During the sample period, the change in population age structure, population education structure, and population occupation structure

  5. Impact of structural aging on seismic risk assessment of reinforced concrete structures in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Ellingwood, B.; Song, J. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Civil Engineering

    1996-03-01

    The Structural Aging Program is addressing the potential for degradation of concrete structural components and systems in nuclear power plants over time due to aging and aggressive environmental stressors. Structures are passive under normal operating conditions but play a key role in mitigating design-basis events, particularly those arising from external challenges such as earthquakes, extreme winds, fires and floods. Structures are plant-specific and unique, often are difficult to inspect, and are virtually impossible to replace. The importance of structural failures in accident mitigation is amplified because such failures may lead to common-cause failures of other components. Structural condition assessment and service life prediction must focus on a few critical components and systems within the plant. Components and systems that are dominant contributors to risk and that require particular attention can be identified through the mathematical formalism of a probabilistic risk assessment, or PRA. To illustrate, the role of structural degradation due to aging on plant risk is examined through the framework of a Level 1 seismic PRA of a nuclear power plant. Plausible mechanisms of structural degradation are found to increase the core damage probability by approximately a factor of two.

  6. SPATIAL-TEMPORAL CHANGES AND TRENDS OF AGEING IN CHINA

    Institute of Scientific and Technical Information of China (English)

    WANG Wu-yi; ZHANG Li; LI Hai-rong; LI Ri-bang; YANG Lin-sheng; LIAO Yong-feng

    2005-01-01

    This study focuses on the development stages of ageing and its regional differences in China based on examination of official statistics and documents. The development of ageing in China has experienced three major stages. Firstly, in the 1950s, low coefficient of elderly population (over 65 years) paced up to primary adult type.Secondly, there was a deeply drop of the elderly population because of natural disaster and political factors in the 1960s. Thirdly, from the 1970s to the end of 20th century, the constant increasing of elderly coefficient made China close to elderly society. With statistic data of population, Logistic model is used to simulate the future development of ageing, and two characteristics of development of ageing are presented. Firstly, as for ageing from 2005 to 2050, the elderly coefficient will grow up significantly from 8.48% to 16.30%. Secondly, after 2025, the increasing rate of elderly coefficient will slow down gradually. The regional differences of elderly population in China can be summarized as follows: 1) the eastern China possesses higher elderly coefficient and huger elder population than the western China; 2) about 47.4% of municipalities and provinces in the eastern China become elderly especially Shanghai, Zhejiang Province, Jiangsu Province, Beijing, Tianjin and Shandong Province; 3) ageing intensity is higher in rural area than urban area but getting close each other, and there are more elderly people in rural area than in urban area. Therefore, these will arose aged care problems, and it becomes important issue to establish the social security system in rural areas as soon as possible for elderly people.

  7. Survivability of integrated PVDF film sensors to accelerated ageing conditions in aeronautical/aerospace structures

    International Nuclear Information System (INIS)

    This work validates the use of integrated polyvinylidene fluoride (PVDF) film sensors for dynamic testing, even after being subjected to UV-thermo-hygro-mechanical accelerated ageing conditions. The verification of PVDF sensors’ survivability in these environmental conditions, typically confronted by civil and military aircraft, is the main concern of the study. The evaluation of survivability is made by a comparison of dynamic testing results provided by the PVDF patch sensors subjected to an accelerated ageing protocol, and those provided by neutral non-aged sensors (accelerometers). The available measurements are the time-domain response signals issued from a modal analysis procedure, and the corresponding frequency response functions (FRF). These are in turn used to identify the constitutive properties of the samples by extraction of the modal parameters, in particular the natural frequencies. The composite specimens in this study undergo different accelerated ageing processes. After several weeks of experimentation, the samples exhibit a loss of stiffness, represented by a decrease in the elastic moduli down to 10%. Despite the ageing, the integrated PVDF sensors, subjected to the same ageing conditions, are still capable of providing reliable data to carry out a close followup of these changes. This survivability is a determinant asset in order to use integrated PVDF sensors to perform structural health monitoring (SHM) in the future of full-scale composite aeronautical structures. (paper)

  8. Common cell biologic and biochemical changes in aging and age-related diseases of the eye: Toward new therapeutic approaches to age-related ocular diseases

    Science.gov (United States)

    Reviews of information about age related macular degeneration (AMD), cataract, and glaucoma make it apparent that while each eye tissue has its own characteristic metabolism, structure and function, there are common perturbations to homeostasis that are associated with age-related dysfunction. The c...

  9. Effects of aging on the function of the urinary system: longitudinal changes with age in selected urine parameters in a hospitalized population of older adults

    Directory of Open Access Journals (Sweden)

    Chmielewski Piotr

    2016-09-01

    Full Text Available Although normal aging does not have a pernicious effect on the homeostasis of fluids, renal reserve in elderly people can be depleted. The purpose of the present study was to assess the relationship between longitudinal changes with age in basic urine parameters (specific gravity and pH in older men and women, depending on their body height and relative body weight. Longitudinal data on these two quantitative traits of the urine were available for 142 physically healthy individuals, including 68 men and 74 women. All subjects were 45 years of age at the beginning and 70 at the end of the period under investigation. All measurements were taken in accordance with internationally accepted requirements. Specific gravity was assessed using a hydrometer, and pH was measured using a pH meter. ANOVA, t-test, and regression analysis were performed. No significant sex differences in specific gravity or urine pH were observed. In both sexes, urine specific gravity decreased with age according to exponential model of regression. In men, there was a gradual increase in the pH of the urine until age 65, and the best fitting regression model was polynomial. In women, on the other hand, there was an exiguous decrease in urine pH throughout the period under study, and the best fitting regression model proved to be exponential. As the process of renal aging commences relatively early in ontogeny and manifests itself in many structural and functional changes, urinalysis and other more sophisticated methods of diagnosis of renal diseases are essential for proper assessment of health status of adults and older individuals. The rate of age-related changes in the analyzed traits of the urine was commensurate in both sexes, thereby revealing no evidence of significant sex differences in terms of renal aging in the period between 45 and 70 years of age.

  10. CHANGES IN STRUCTURE OF ROMANIA'S INTERNATIONAL TRADE

    Directory of Open Access Journals (Sweden)

    CECILIA IRINA RABONTU

    2014-05-01

    Full Text Available Evolution of structural changes in Romanian trade is somewhat interesting if you look at it from the perspective of mutations that occurred in the categories of goods and services subject to international trade. After the Revolution of 1989, the Romanian economy has gone through dramatic changes that had determinate a total reconfiguration of foreign trade. At the same time, the economic instability has had further repercussions on the Romanian economy manifested through higher prices, reduced wages or earnings, reduced employment and rising unemployment, increasing interest rates on loans due to the devaluation of the national currency, increase value-added tax, consumption reduction etc. We proposed in this paper an analyze for a significant period of time evolution of international trade in goods and services of Romania in order to establish the main categories of goods traded but Romania's main trading partners, too. In order to achieve the central goal of this paper we will use statistical data found in the databases provided by the WTO, Eurostat and the National Statistical Institutes and statistical methods to support our initiative.

  11. Estimation of Energy Consumption and Greenhouse Gas Emissions considering Aging and Climate Change in Residential Sector

    Science.gov (United States)

    Lee, M.; Park, C.; Park, J. H.; Jung, T. Y.; Lee, D. K.

    2015-12-01

    The impacts of climate change, particularly that of rising temperatures, are being observed across the globe and are expected to further increase. To counter this phenomenon, numerous nations are focusing on the reduction of greenhouse gas (GHG) emissions. Because energy demand management is considered as a key factor in emissions reduction, it is necessary to estimate energy consumption and GHG emissions in relation to climate change. Further, because South Korea is the world's fastest nation to become aged, demographics have also become instrumental in the accurate estimation of energy demands and emissions. Therefore, the purpose of this study is to estimate energy consumption and GHG emissions in the residential sectors of South Korea with regard to climate change and aging to build more accurate strategies for energy demand management and emissions reduction goals. This study, which was stablished with 2010 and 2050 as the base and target years, respectively, was divided into a two-step process. The first step evaluated the effects of aging and climate change on energy demand, and the second estimated future energy use and GHG emissions through projected scenarios. First, aging characteristics and climate change factors were analyzed by using the logarithmic mean divisia index (LMDI) decomposition analysis and the application of historical data. In the analysis of changes in energy use, the effects of activity, structure, and intensity were considered; the degrees of contribution were derived from each effect in addition to their relations to energy demand. Second, two types of scenarios were stablished based on this analysis. The aging scenarios are business as usual and future characteristics scenarios, and were used in combination with Representative Concentration Pathway (RCP) 2.6 and 8.5. Finally, energy consumption and GHG emissions were estimated by using a combination of scenarios. The results of these scenarios show an increase in energy consumption

  12. Endplates Changes Related to Age and Vertebral Segment

    Directory of Open Access Journals (Sweden)

    Carlos Fernando P. S. Herrero

    2014-01-01

    Full Text Available Endplate separations are defined as the presence of a space between the hyaline cartilage and the cortical bone of the adjacent vertebral body. This study evaluates endplate separations from the vertebral body and intervertebral discs and verifies if endplate separation is related to age and the spinal level. Groups were formed based on age (20–40 and 41–85 years old and the vertebral segment (T7-T8 and L4-L5 segments. Histological analysis included assessment of the length of the vertebral endplates, the number and dimensions of the separations, and orientation of the collagen fibers, in the mid-sagittal slice. Two indexes were created: the separation index (number of separations/vertebral length and separation extension index (sum of all separations/vertebral length. The results of the study demonstrated a direct relationship between the density of separations in the endplate and two variables: age and spinal level.

  13. Definitions of fitness in age-structured populations: Comparison in the haploid case.

    Science.gov (United States)

    Lessard, Sabin; Soares, Cintia

    2016-02-21

    Fisher's (1930) Fundamental Theorem of Natural Selection (FTNS), and in particular the development of an explicit age-structured version of the theorem, is of everlasting interest. In a recent paper, Grafen (2015a) argues that Fisher regarded his theorem as justifying individual rather than population fitness maximization. The argument relies on a new definition of fitness in age-structured populations in terms of individual birth and death rates and age-specific reproductive values in agreement with a principle of neutrality. The latter are frequency-dependent and defined without reference to genetic variation. In the same paper, it is shown that the rate of increase in the mean of the breeding values of fitness weighted by the reproductive values, but keeping the breeding values constant as in Price (1972) is equal to the additive genetic variance in fitness. Therefore, this partial change is obtained by keeping constant not only the genotypic birth and death rates but also the mean age-specific birth and death rates from which the age-specific reproductive values are defined. In this paper we reaffirm that the Malthusian parameter which measures the relative rate of increase or decrease in reproductive value of each genotype in a continuous-time age-structured population is the definition of fitness used in Fisher's (1930) FTNS. This is shown by considering an age-structured asexual haploid population with constant age-specific birth and death (or survival) parameters for each type. Although the original statement of the FTNS is for a diploid population, this simplified haploid model allows us to address the definition of fitness meant in this theorem without the complexities and effects of a changing genic environment. In this simplified framework, the rate of change in mean fitness in continuous time is expected to be exactly equal to the genetic variance in fitness (or to the genetic variance in fitness divided by the mean fitness in discrete time), which can

  14. Definitions of fitness in age-structured populations: Comparison in the haploid case.

    Science.gov (United States)

    Lessard, Sabin; Soares, Cintia

    2016-02-21

    Fisher's (1930) Fundamental Theorem of Natural Selection (FTNS), and in particular the development of an explicit age-structured version of the theorem, is of everlasting interest. In a recent paper, Grafen (2015a) argues that Fisher regarded his theorem as justifying individual rather than population fitness maximization. The argument relies on a new definition of fitness in age-structured populations in terms of individual birth and death rates and age-specific reproductive values in agreement with a principle of neutrality. The latter are frequency-dependent and defined without reference to genetic variation. In the same paper, it is shown that the rate of increase in the mean of the breeding values of fitness weighted by the reproductive values, but keeping the breeding values constant as in Price (1972) is equal to the additive genetic variance in fitness. Therefore, this partial change is obtained by keeping constant not only the genotypic birth and death rates but also the mean age-specific birth and death rates from which the age-specific reproductive values are defined. In this paper we reaffirm that the Malthusian parameter which measures the relative rate of increase or decrease in reproductive value of each genotype in a continuous-time age-structured population is the definition of fitness used in Fisher's (1930) FTNS. This is shown by considering an age-structured asexual haploid population with constant age-specific birth and death (or survival) parameters for each type. Although the original statement of the FTNS is for a diploid population, this simplified haploid model allows us to address the definition of fitness meant in this theorem without the complexities and effects of a changing genic environment. In this simplified framework, the rate of change in mean fitness in continuous time is expected to be exactly equal to the genetic variance in fitness (or to the genetic variance in fitness divided by the mean fitness in discrete time), which can

  15. Age-related changes in ac-impedance spectroscopy studies of normal human dentine: further investigations.

    Science.gov (United States)

    Eldarrat, A H; High, A S; Kale, G M

    2010-01-01

    One of the age-related changes occurring in dentine structure is the formation of peritubular dentine on the inner walls of dentinal tubules leading to complete closure of tubules. Ac-impedance is safe, fast and non-invasive technique. In the last decade, the popularity of the technique has increased in dental research. Several investigators have used the technique to detect tooth cracks and caries. The results of in vitro studies showed that ac-impedance technique was more advanced for caries detection than visual and radiographic methods. However, other studies demonstrated that the accuracy of impedance measurements can be affected by many factors such as remineralization after tooth eruption. A study has been published on effect of age on impedance measurements by the authors for two age groups by employing ac-impedance spectroscopy. Therefore, the aim of this study was to demonstrate the importance of this technique by conducting further investigations on dentine samples of wider age groups. Dentine samples were prepared from extracted sound third molars of known patient age. The ac-impedance measurements were carried out over a wide range of frequency. After performing all electrical measurements, dentine samples were examined under SEM to correlate the electrical measurements with their structure. Impedance measurements showed that there were differences in impedance between young and old dentine. One-way ANOVA of the means of resistance and capacitance for all age groups (20, 25, 30, 40 and 50 years old dentine) revealed a significant difference (ANOVA, P < 0.0001) as a function of age. Applying Tukey's post hoc test, to the same data showed that this difference was due to the 50 years old dentine for resistance and was due to the 40 and 50 years old dentine for capacitance which were statistically different to all other groups. SEM investigation of dentine samples showed that young dentine is characterized by open dentinal tubules distributed all over the

  16. Aging changes in the heart and blood vessels

    Science.gov (United States)

    ... for treating high blood pressure, high cholesterol or diabetes. Reduce or stop smoking. Men between the ages of 65 to 75 who have ever smoked should be screened for aneurysms in their abdominal aorta. Get more exercise: Exercise may help prevent obesity, ...

  17. Basement membrane changes in capillaries of the ageing human retina

    Science.gov (United States)

    Powner, Michael B; Scott, Andrew; Zhu, Meidong; Munro, Peter M G; Foss, Alexander J E; Hageman, Gregory S; Gillies, Mark C; Fruttiger, Marcus

    2014-01-01

    Objectives The ultrastructural appearance of retinal capillaries can yield important information about disease mechanisms, but is not well characterised in human post mortem samples. We therefore aimed to create a baseline for the appearance of capillaries and establish how this is influenced by post mortem fixation delays and donor age. Methods Electron microscopy was used to characterise retinal capillaries in 20 anonymous donors (with no known eye diseases) of various ages and with various post mortem fixation delays. In addition, samples from six patients with conditions that are known to affect the retinal vasculature (four cases of type 2 diabetes without diabetic retinopathy, one case of diabetic retinopathy and one case of macular telangiectasia type 2) were analysed. Results Vacuoles were found in capillary basement membranes at the vessel—glia interface in all samples, from both the normal and disease cases. Vacuole frequency increased with donor age but was not influenced by post mortem fixation delays. Conclusion Vacuoles in the basement membrane are a normal feature of adult human retinal capillaries and do not indicate disease. Their incidence increases with age and might be a contributing factor to late-onset pathologies of the retinal vasculature. PMID:21606466

  18. Changes in skeletal muscle with aging: effects of exercise training.

    Science.gov (United States)

    Rogers, M A; Evans, W J

    1993-01-01

    There is an approximate 30% decline in muscle strength and a 40% reduction in muscle area between the second and seventh decades of life. Thus, the loss of muscle mass with aging appears to be the major factor in the age-related loss of muscle strength. The loss of muscle mass is partially due to a significant decline in the numbers of both Type I and Type II muscle fibers plus a decrease in the size of the muscle cells, with the Type II fibers showing a preferential atrophy. There appears to be no loss of glycolytic capacity in senescent skeletal muscle whereas muscle oxidative enzyme activity and muscle capillarization decrease by about 25%. Vigorous endurance exercise training in older people, where the stimulus is progressively increased, elicits a proliferation of muscle capillaries, an increase in oxidative enzyme activity, and a significant improvement in VO2max. Likewise, progressive resistive training in older individuals results in muscle hypertrophy and increased strength, if the training stimulus is of a sufficient intensity and duration. Since older individuals adapt to resistive and endurance exercise training in a similar fashion to young people, the decline in the muscle's metabolic and force-producing capacity can no longer be considered as an inevitable consequence of the aging process. Rather, the adaptations in aging skeletal muscle to exercise training may prevent sarcopenia, enhance the ease of carrying out the activities of daily living, and exert a beneficial effect on such age-associated diseases as Type II diabetes, coronary artery disease, hypertension, osteoporosis, and obesity. PMID:8504850

  19. Radical Change Theory and Synergistic Reading for Digital Age Youth

    Science.gov (United States)

    Dresang, Eliza T.; Kotrla, Bowie

    2009-01-01

    While it was perfectly clear to almost everyone during the 1990s that technology was changing, almost no one acknowledged the concomitant change in a sizeable and growing cadre of handheld books for youth. Some of those who did notice expressed puzzlement and regret at the break from a more traditional form and format; others expressed curiosity.…

  20. MRI of the normal brain from early childhood to middle age. Pt. 2. Age dependence of signal intensity changes on T2-weighted images

    International Nuclear Information System (INIS)

    We examined 66 healthy volunteers aged 4 to 50 years by magnetic resonance imaging (MRI) and the signal intensity was measured on T2-weighted images in numerous sites and correlated with age and sex. Using distilled water and cerebrospinal fluid (CSF) as references on each slice, we calculated the signal intensities of the brain structures. Calculated ratios between structures did not change with age, except for those of the globus pallidus and thalamus, in which the signal intensities decreased more rapidly. The signal intensities of other brain structures changed equally but this could not be discerned visually and quantitative measurements were required. The signal intensities in the white and deep grey matter decreased rapidly in the first decade and then gradually to reach a plateau after the age of 18 years. Maturation of the brain thus seems to continue until near the end of the second decade of life. No sex differences were found. Quantitative analysis requires intensity references. The CSF in the tips of the frontal horns seems to be as reliable as an external fluid reference for intensity, and can be used in routine examinations provided the frontal horns are large enough to avoid partial volume effect. (orig.)

  1. Changes in the radiocarbon reservoir age in Lake Xingyun, Southwestern China during the Holocene.

    Directory of Open Access Journals (Sweden)

    Aifeng Zhou

    Full Text Available Chronology is a necessary component of paleoclimatology. Radiocarbon dating plays a central role in determining the ages of geological samples younger than ca. 50 ka BP. However, there are many limitations for its application, including radiocarbon reservoir effects, which may cause incorrect chronology in many lakes. Here we demonstrate temporal changes in the radiocarbon reservoir age of Lake Xingyun, Southwestern China, where radiocarbon ages based on bulk organic matter have been reported in previous studies. Our new radiocarbon ages, determined from terrestrial plant macrofossils suggest that the radiocarbon reservoir age changed from 960 to 2200 years during the last 8500 cal a BP years. These changes to the reservoir effect were associated with inputs from either pre-aged organic carbon or 14C-depleted hard water in Lake Xingyun caused by hydrological change in the lake system. The radiocarbon reservoir age may in return be a good indicator for the carbon source in lake ecosystems and depositional environment.

  2. Proteomic analysis reveals age-related changes in tendon matrix composition, with age- and injury-specific matrix fragmentation.

    Science.gov (United States)

    Peffers, Mandy J; Thorpe, Chavaunne T; Collins, John A; Eong, Robin; Wei, Timothy K J; Screen, Hazel R C; Clegg, Peter D

    2014-09-12

    Energy storing tendons, such as the human Achilles and equine superficial digital flexor tendon (SDFT), are highly prone to injury, the incidence of which increases with aging. The cellular and molecular mechanisms that result in increased injury in aged tendons are not well established but are thought to result in altered matrix turnover. However, little attempt has been made to fully characterize the tendon proteome nor determine how the abundance of specific tendon proteins changes with aging and/or injury. The aim of this study was, therefore, to assess the protein profile of normal SDFTs from young and old horses using label-free relative quantification to identify differentially abundant proteins and peptide fragments between age groups. The protein profile of injured SDFTs from young and old horses was also assessed. The results demonstrate distinct proteomic profiles in young and old tendon, with alterations in the levels of proteins involved in matrix organization and regulation of cell tension. Furthermore, we identified several new peptide fragments (neopeptides) present in aged tendons, suggesting that there are age-specific cleavage patterns within the SDFT. Proteomic profile also differed between young and old injured tendon, with a greater number of neopeptides identified in young injured tendon. This study has increased the knowledge of molecular events associated with tendon aging and injury, suggesting that maintenance and repair of tendon tissue may be reduced in aged individuals and may help to explain why the risk of injury increases with aging. PMID:25077967

  3. Age structure of elephants in Liwonde National Park, Malawi

    Directory of Open Access Journals (Sweden)

    R. Bhima

    1997-02-01

    Full Text Available The age structure of the elephant population in Liwonde National Park, Malawi was determined for the first time in 1993 and again in 1995 using the photogrammetric method. Sampling was done during a four year-long severe drought from 1991/92 to 1994/95. The drought reached its highest intensity in the first year. Therefore, the study also attempted to assess the impact of the drought on the population. The results show that the population consisted of mostly young animals <5 years old (52.6 and 44.8 in 1993 and 1995, respectively. The other age cohorts were as follows: 6-10 years old - 16.1 and 21.7 ; 11-15 years old - 7.8 and 9.2 ; 16-20 years old - 5.2 and 4.7 ; and >20 years old - 18.3 and 20.5 . The population is young and growing. The prolonged drought did not have any significant impact on the population.

  4. Understanding Age-Related Changes in Skeletal Muscle Metabolism: Differences Between Females and Males.

    Science.gov (United States)

    Gheller, Brandon J F; Riddle, Emily S; Lem, Melinda R; Thalacker-Mercer, Anna E

    2016-07-17

    Skeletal muscle is the largest metabolic organ system in the human body. As such, metabolic dysfunction occurring in skeletal muscle impacts whole-body nutrient homeostasis. Macronutrient metabolism changes within the skeletal muscle with aging, and these changes are associated in part with age-related skeletal muscle remodeling. Moreover, age-related changes in skeletal muscle metabolism are affected differentially between males and females and are likely driven by changes in sex hormones. Intrinsic and extrinsic factors impact observed age-related changes and sex-related differences in skeletal muscle metabolism. Despite some support for sex-specific differences in skeletal muscle metabolism with aging, more research is necessary to identify underlying differences in mechanisms. Understanding sex-specific aging skeletal muscle will assist with the development of therapies to attenuate adverse metabolic and functional outcomes. PMID:27431365

  5. Changes within the immune system from Birth to Old Age

    OpenAIRE

    Grubeck-Loebenstein, Beatrix; Herndler-Brandstetter, Dietmar

    2008-01-01

    A wide range of age-related alterations in immune system function have been described which contribute to the high prevalence, the more severe disease course and the poorer prognosis of certain infectious diseases in the elderly population and the low efficacy of vaccinations. Moreover, the development and progression of other agerelated diseases, such as certain cancers, atherosclerosis, dementia, osteoporosis and rheumatoid arthritis have been associated with altered immune function in old ...

  6. [Biological Age as a Method for Systematic Assessment of Ontogenetic Changes in the State of an Organism].

    Science.gov (United States)

    Dontsov, V I; Krut'ko, V N

    2015-01-01

    Aging is a common feature of living and nonliving systems as a disturbance of the structure of the system accumulating with age. The only cause of aging of a living system, which is capable of renewal, is the insufficiency of renewal. The latter manifests itself as two global mechanisms of aging: the genetically determined nonrenewal of a number of structures that can only die with age (stochastic aging) and the regulatory reduction in the rate of self-renewal of living structures. The regulatory reduction in cellular self-renewal (cell growth and division) is most important. At the same chronological age, the degree of aging of the organism in general, as well as individual organs, cells, and systems of the organism, may be different, reflecting the concept of biological age (BA)--an indicator of the level of development, changes, or deterioration of a structure or function of an element of the organism, a functional system, or the organism as a whole. It is expressed in units oftime by relating the values of biomarkers defining the processes of aging with the standard average statistical dependences of changes in these biomarkers with the chronological age. The concept of BA is directly related to the concept of viability of the organism, which is determined by the sum (integral) of viabilities of its parts (in practice, the residual functional resource). For quantitative characterization of aging in general, the index of integrated biological age is used. To give a detailed characterization, the partial biological ages are used, which reflect the aging of different systems of the organism, as well as a number of indices reflecting its functional and psychological possibilities. The contribution of pathological processes to BA is also taken into account. In addition, the amount of retained adaptive reserves in the physical and nervous and mental aspects, the risk factors, and the factors of longevity should be determined. For this purpose, it is necessary to take

  7. Changes of hygroscopicity and morphology during ageing of diesel soot

    Energy Technology Data Exchange (ETDEWEB)

    Tritscher, Torsten; Juranyi, Zsofia; Chirico, Roberto; Gysel, Martin; Heringa, Maarten F; DeCarlo, Peter F; Prevot, Andre S H; Weingartner, Ernest; Baltensperger, Urs [Laboratory of Atmospheric Chemistry, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Martin, Maria; Sierau, Berko, E-mail: Ernest.Weingartner@psi.ch [Institute of Atmospheric and Climate Sciences, ETH Zurich, Universitaetsstrasse 16, 8092 Zurich (Switzerland)

    2011-07-15

    Soot particles are an important component of atmospheric aerosol and their interaction with water is important for their climate effects. The hygroscopicity of fresh and photochemically aged soot and secondary organic aerosol (SOA) from diesel passenger car emissions was studied under atmospherically relevant conditions in a smog chamber at sub-and supersaturation of water vapor. Fresh soot particles show no significant hygroscopic growth nor cloud condensation nucleus (CCN) activity. Ageing by condensation of SOA formed by photooxidation of the volatile organic carbon (VOC) emission leads to increased water uptake and CCN activity as well as to a compaction of the initially non-spherical soot particles when exposed to high relative humidity (RH). It is important to consider the latter effect for the interpretation of mobility based measurements. The vehicle with oxidation catalyst (EURO3) emits much fewer VOCs than the vehicle without after-treatment (EURO2). Consequently, more SOA is formed for the latter, resulting in more pronounced effects on particle hygroscopicity and CCN activity. Nevertheless, the aged soot particles did not reach the hygroscopicity of pure SOA particles formed from diesel VOC emissions, which are similarly hygroscopic (0.06 < {kappa}{sub H-TDMA} < 0.12 and 0.09 < {kappa}{sub CCN} < 0.14) as SOA from other precursor gases investigated in previous studies.

  8. Changes of hygroscopicity and morphology during ageing of diesel soot

    International Nuclear Information System (INIS)

    Soot particles are an important component of atmospheric aerosol and their interaction with water is important for their climate effects. The hygroscopicity of fresh and photochemically aged soot and secondary organic aerosol (SOA) from diesel passenger car emissions was studied under atmospherically relevant conditions in a smog chamber at sub-and supersaturation of water vapor. Fresh soot particles show no significant hygroscopic growth nor cloud condensation nucleus (CCN) activity. Ageing by condensation of SOA formed by photooxidation of the volatile organic carbon (VOC) emission leads to increased water uptake and CCN activity as well as to a compaction of the initially non-spherical soot particles when exposed to high relative humidity (RH). It is important to consider the latter effect for the interpretation of mobility based measurements. The vehicle with oxidation catalyst (EURO3) emits much fewer VOCs than the vehicle without after-treatment (EURO2). Consequently, more SOA is formed for the latter, resulting in more pronounced effects on particle hygroscopicity and CCN activity. Nevertheless, the aged soot particles did not reach the hygroscopicity of pure SOA particles formed from diesel VOC emissions, which are similarly hygroscopic (0.06 H-TDMA CCN < 0.14) as SOA from other precursor gases investigated in previous studies.

  9. Age and growth of the mutton hamlet Alphestes afer, with a review of the size and age of sex change among epinephelids.

    Science.gov (United States)

    Marques, S; Ferreira, B P

    2016-07-01

    This paper presents results on the age, growth and population structure of a small grouper, the mutton hamlet Alphestes afer, and discusses the observed size and age structure patterns in relation to reproductive strategies among the epinephelids. Ages were determined by examination of sectioned otoliths, which showed a distinct pattern of alternating translucent and opaque zones that formed annually, as validated with tetracycline labelling. The von Bertalanffy growth function was adjusted to the length-at-age data of the males and females, but no significant differences were observed between the resulting parameters. The females, however, were older at given sizes and attained larger sizes and ages, with a maximum observed longevity of 13 years and a total length (LT ) of 26 cm, while the males attained maximum longevities of only 10 years and a 22 cm maximum LT . The LT and age range for the sex change was 16-25 cm and 3-11 years. The total mortality rate (Z) was estimated to be 0·55 for females and 0·82 for males. With the males younger and smaller than the females, this species differed from the pattern commonly observed for protogynous epinephelids. Males had slower growth after maturation, probably due to energy allocation to sperm production during sexual development. This study shows that demography is an important tool to understand the pathways for reproductive strategies in grouper populations. PMID:27073155

  10. Age and growth of the mutton hamlet Alphestes afer, with a review of the size and age of sex change among epinephelids.

    Science.gov (United States)

    Marques, S; Ferreira, B P

    2016-07-01

    This paper presents results on the age, growth and population structure of a small grouper, the mutton hamlet Alphestes afer, and discusses the observed size and age structure patterns in relation to reproductive strategies among the epinephelids. Ages were determined by examination of sectioned otoliths, which showed a distinct pattern of alternating translucent and opaque zones that formed annually, as validated with tetracycline labelling. The von Bertalanffy growth function was adjusted to the length-at-age data of the males and females, but no significant differences were observed between the resulting parameters. The females, however, were older at given sizes and attained larger sizes and ages, with a maximum observed longevity of 13 years and a total length (LT ) of 26 cm, while the males attained maximum longevities of only 10 years and a 22 cm maximum LT . The LT and age range for the sex change was 16-25 cm and 3-11 years. The total mortality rate (Z) was estimated to be 0·55 for females and 0·82 for males. With the males younger and smaller than the females, this species differed from the pattern commonly observed for protogynous epinephelids. Males had slower growth after maturation, probably due to energy allocation to sperm production during sexual development. This study shows that demography is an important tool to understand the pathways for reproductive strategies in grouper populations.

  11. Aging and Wisdom: Age-related changes in economic and social decision making

    Directory of Open Access Journals (Sweden)

    Kenneth eLim

    2015-06-01

    Full Text Available World life expectancy is increasing and many populations will begin to age rapidly. The impeding prevalence of a greater number of older people living longer lives will have significant social and economic implications. It is important to understand how older people make economic and social decisions. Aging can be associated with a ‘phenomenon of decline’ and also greater wisdom. This paper seeks to examine the relationship between wisdom and aging. It reviews and connects the behavioral sciences and neuroscience literature on age differences in the following social and economic decision making domains that represent subcomponents of wisdom: 1 prosocial behavior in experimental economic games and competitive situations, 2 resolving social conflicts, 3 emotional homeostasis, 4 self-reflection, 5 dealing effectively with uncertainty in the domains of risk, ambiguity and intertemporal choice. Overall, we find a lack of research into how older people make economic and social decisions. There is, however, some evidence that older adults outperform young adults on certain subcomponents of wisdom, but the exact relationship between old age and each subcomponent remains unclear. A better understanding of these relationships holds the potential to alleviate a wide range of mental health problems, and has broad implications for social policies aimed at the elderly.

  12. Changes in soil bacterial community structure with increasing disturbance frequency.

    Science.gov (United States)

    Kim, Mincheol; Heo, Eunjung; Kang, Hojeong; Adams, Jonathan

    2013-07-01

    Little is known of the responsiveness of soil bacterial community structure to disturbance. In this study, we subjected a soil microcosm to physical disturbance, sterilizing 90 % of the soil volume each time, at a range of frequencies. We analysed the bacterial community structure using 454 pyrosequencing of the 16S rRNA gene. Bacterial diversity was found to decline with the increasing disturbance frequencies. Total bacterial abundance was, however, higher at intermediate and high disturbance frequencies, compared to low and no-disturbance treatments. Changing disturbance frequency also led to changes in community composition, with changes in overall species composition and some groups becoming abundant at the expense of others. Some phylogenetic groups were found to be relatively more disturbance-sensitive or tolerant than others. With increasing disturbance frequency, phylogenetic species variability (an index of community composition) itself became more variable from one sample to another, suggesting a greater role of chance in community composition. Compared to the tightly clustered community of the original undisturbed soil, in all the aged disturbed soils the lists of most abundant operational taxonomic units (OTUs) in each replicate were very different, suggesting a possible role of stochasticity in resource colonization and exploitation in the aged and disturbed soils. For example, colonization may be affected by whichever localized concentrations of bacterial populations happen to survive the last disturbance and be reincorporated in abundance into each pot. Overall, it appears that the soil bacterial community is very sensitive to physical disturbance, losing diversity, and that certain groups have identifiable 'high disturbance' vs. 'low disturbance' niches.

  13. Review Symposium on "Changing Teachers, Changing Times: Teachers' Work and Culture in the Postmodern Age," by Andy Hargreaves.

    Science.gov (United States)

    Strain, Michael

    1994-01-01

    In this review symposium on Andy Hargreaves's book "Changing Teachers, Changing Times: Teachers' Work and Culture in the Postmodern Age" (1994), Strain questions Hargreaves's treatment of modernity, postmodernism, and postmodernity and his materialistic, functionalist view of history and social change. Wong applauds Hargreaves' analysis of…

  14. Physiological and psychosocial age-related changes associated with reduced food intake in older persons

    NARCIS (Netherlands)

    de Boer, Antina; Ter Horst, Gert J.; Lorist, Monicque M.

    2013-01-01

    Dietary intake changes during the course of aging. Normally an increase in food intake is observed around 55 years of age, which is followed by a reduction in food intake in individuals over 65 years of age. This reduction in dietary intake results in lowered levels of body fat and body weight, a ph

  15. Multiple gait parameters derived from iPod accelerometry predict age-related gait changes

    NARCIS (Netherlands)

    Kosse, Nienke; Vuillerme, Nicolas; Hortobagyi, Tibor; Lamoth, Claude

    2016-01-01

    Introduction Normative data of how natural aging affects gait can serve as a frame of reference for changes in gait dynamics due to pathologies. Therefore, the present study aims (1) to identify gait variables sensitive to age-related changes in gait over the adult life span using the iPod and (2) t

  16. Learning to Manage Change in the Third Age

    Science.gov (United States)

    Innocent, Natasha

    2010-01-01

    Everyone is living through a period of considerable demographic change, which is predicted to continue and escalate. People are living longer and, generally, healthier lives, and the lifelong learning system in the UK needs to catch-up with this new reality. There is a need for a much more flexible approach that offers choice and opportunities to…

  17. White matter structure changes as adults learn a second language.

    Science.gov (United States)

    Schlegel, Alexander A; Rudelson, Justin J; Tse, Peter U

    2012-08-01

    Traditional models hold that the plastic reorganization of brain structures occurs mainly during childhood and adolescence, leaving adults with limited means to learn new knowledge and skills. Research within the last decade has begun to overturn this belief, documenting changes in the brain's gray and white matter as healthy adults learn simple motor and cognitive skills [Lövdén, M., Bodammer, N. C., Kühn, S., Kaufmann, J., Schütze, H., Tempelmann, C., et al. Experience-dependent plasticity of white-matter microstructure extends into old age. Neuropsychologia, 48, 3878-3883, 2010; Taubert, M., Draganski, B., Anwander, A., Müller, K., Horstmann, A., Villringer, A., et al. Dynamic properties of human brain structure: Learning-related changes in cortical areas and associated fiber connections. The Journal of Neuroscience, 30, 11670-11677, 2010; Scholz, J., Klein, M. C., Behrens, T. E. J., & Johansen-Berg, H. Training induces changes in white-matter architecture. Nature Neuroscience, 12, 1370-1371, 2009; Draganski, B., Gaser, C., Busch, V., Schuirer, G., Bogdahn, U., & May, A. Changes in grey matter induced by training. Nature, 427, 311-312, 2004]. Although the significance of these changes is not fully understood, they reveal a brain that remains plastic well beyond early developmental periods. Here we investigate the role of adult structural plasticity in the complex, long-term learning process of foreign language acquisition. We collected monthly diffusion tensor imaging scans of 11 English speakers who took a 9-month intensive course in written and spoken Modern Standard Chinese as well as from 16 control participants who did not study a language. We show that white matter reorganizes progressively across multiple sites as adults study a new language. Language learners exhibited progressive changes in white matter tracts associated with traditional left hemisphere language areas and their right hemisphere analogs. Surprisingly, the most significant changes

  18. White matter structure changes as adults learn a second language.

    Science.gov (United States)

    Schlegel, Alexander A; Rudelson, Justin J; Tse, Peter U

    2012-08-01

    Traditional models hold that the plastic reorganization of brain structures occurs mainly during childhood and adolescence, leaving adults with limited means to learn new knowledge and skills. Research within the last decade has begun to overturn this belief, documenting changes in the brain's gray and white matter as healthy adults learn simple motor and cognitive skills [Lövdén, M., Bodammer, N. C., Kühn, S., Kaufmann, J., Schütze, H., Tempelmann, C., et al. Experience-dependent plasticity of white-matter microstructure extends into old age. Neuropsychologia, 48, 3878-3883, 2010; Taubert, M., Draganski, B., Anwander, A., Müller, K., Horstmann, A., Villringer, A., et al. Dynamic properties of human brain structure: Learning-related changes in cortical areas and associated fiber connections. The Journal of Neuroscience, 30, 11670-11677, 2010; Scholz, J., Klein, M. C., Behrens, T. E. J., & Johansen-Berg, H. Training induces changes in white-matter architecture. Nature Neuroscience, 12, 1370-1371, 2009; Draganski, B., Gaser, C., Busch, V., Schuirer, G., Bogdahn, U., & May, A. Changes in grey matter induced by training. Nature, 427, 311-312, 2004]. Although the significance of these changes is not fully understood, they reveal a brain that remains plastic well beyond early developmental periods. Here we investigate the role of adult structural plasticity in the complex, long-term learning process of foreign language acquisition. We collected monthly diffusion tensor imaging scans of 11 English speakers who took a 9-month intensive course in written and spoken Modern Standard Chinese as well as from 16 control participants who did not study a language. We show that white matter reorganizes progressively across multiple sites as adults study a new language. Language learners exhibited progressive changes in white matter tracts associated with traditional left hemisphere language areas and their right hemisphere analogs. Surprisingly, the most significant changes

  19. Esophageal morphometric and biomechanical changes during aging in rats

    DEFF Research Database (Denmark)

    Zhao, Jingbo; Gregersen, Hans

    of experiment. Morphometry data were obtained by measuring the wall thickness and cross-sectional area. The mechanical test was performed as a step-wise distension experiment. The esophageal diameter and length were obtained from digitized images of the segments at pre-selected pressures and at no-load and zero-stress...... states. Circumferential and longitudinal stresses (force per area) and strains (deformation) were computed from the length, diameter and pressure data and from the zero-stress state geometry. Results The esophageal dimensions increased slightly from 6 to 22 months, e.g. the weight per unit length......, the wall thickness and the wall cross-sectional area increased about 17%, 18% and 35% respectively. The opening angle was gradually decreased from 90 degrees to 67 degrees during aging. The circumferential stress-strain curves shifted to the left after 12 month (p

  20. Intestinal morphometric and biomechanical changes during aging in rats

    DEFF Research Database (Denmark)

    Zhao, Jingbo; Gregersen, Hans

    2015-01-01

    . The mechanical test was performed as a step-wise distension experiment. The intestinal diameter and length were obtained from digitized images of the segments at pre-selected pressures and at no-load and zero-stress states. Circumferential and longitudinal stresses (force per area) and strains (deformation) were...... computed from the length, diameter and pressure data and from the zero-stress state geometry. Results: The duodenal and ileal dimensions increased slightly from 6 to 22 months, e.g. the weight per unit length, the wall thickness and the wall cross-sectional area increased 20%, 4% ,and 25% for duodenum...... and 12%, 5%, and 8% for ileum, respectively. The opening angle gradually decreased from 154 to 117 degrees for duodenum and from 144 to 87 degrees for ileum as function of aging. The circumferential stress-strain curves shifted to the left after 22 months (pstress...

  1. A Drosophila model for age-associated changes in sleep:wake cycles.

    Science.gov (United States)

    Koh, Kyunghee; Evans, Joshua M; Hendricks, Joan C; Sehgal, Amita

    2006-09-12

    One of the most consistent behavioral changes that occurs with age in humans is the loss of sleep consolidation. This can be quite disruptive and yet little is known about its underlying basis. To better understand the effects of aging on sleep:wake cycles, we sought to study this problem in Drosophila melanogaster, a powerful system for research on aging and behavior. By assaying flies of different ages as well as monitoring individual flies constantly over the course of their lifetime, we found that the strength of sleep:wake cycles decreased and that sleep became more fragmented with age in Drosophila. These changes in sleep:wake cycles became faster or slower with manipulations of ambient temperature that decreased or increased lifespan, respectively, demonstrating that they are a function of physiological rather than chronological age. The effect of temperature on lifespan was not mediated by changes in overall activity level or sleep amount. Flies treated with the oxidative stress-producing reagent paraquat showed a breakdown of sleep:wake cycles similar to that seen with aging, leading us to propose that the accumulation of oxidative damage with age contributes to the changes in rhythm and sleep. Together, these findings establish Drosophila as a valuable model for studying age-associated sleep fragmentation and breakdown of rhythm strength, and indicate that these changes in sleep:wake cycles are an integral part of the physiological aging process. PMID:16938867

  2. Age-related changes in the plasticity and toughness of human cortical bone at multiple length-scales

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, Elizabeth A.; Schaible, Eric; Bale, Hrishikesh; Barth, Holly D.; Tang, Simon Y.; Reichert, Peter; Busse, Bjoern; Alliston, Tamara; Ager III, Joel W.; Ritchie, Robert O.

    2011-08-10

    The structure of human cortical bone evolves over multiple length-scales from its basic constituents of collagen and hydroxyapatite at the nanoscale to osteonal structures at nearmillimeter dimensions, which all provide the basis for its mechanical properties. To resist fracture, bone’s toughness is derived intrinsically through plasticity (e.g., fibrillar sliding) at structural-scales typically below a micron and extrinsically (i.e., during crack growth) through mechanisms (e.g., crack deflection/bridging) generated at larger structural-scales. Biological factors such as aging lead to a markedly increased fracture risk, which is often associated with an age-related loss in bone mass (bone quantity). However, we find that age-related structural changes can significantly degrade the fracture resistance (bone quality) over multiple lengthscales. Using in situ small-/wide-angle x-ray scattering/diffraction to characterize sub-micron structural changes and synchrotron x-ray computed tomography and in situ fracture-toughness measurements in the scanning electron microscope to characterize effects at micron-scales, we show how these age-related structural changes at differing size-scales degrade both the intrinsic and extrinsic toughness of bone. Specifically, we attribute the loss in toughness to increased non-enzymatic collagen cross-linking which suppresses plasticity at nanoscale dimensions and to an increased osteonal density which limits the potency of crack-bridging mechanisms at micron-scales. The link between these processes is that the increased stiffness of the cross-linked collagen requires energy to be absorbed by “plastic” deformation at higher structural levels, which occurs by the process of microcracking.

  3. Visceral adipose tissue inflammation is associated with age-related brain changes and ischemic brain damage in aged mice.

    Science.gov (United States)

    Shin, Jin A; Jeong, Sae Im; Kim, Minsuk; Yoon, Joo Chun; Kim, Hee-Sun; Park, Eun-Mi

    2015-11-01

    Visceral adipose tissue is accumulated with aging. An increase in visceral fat accompanied by low-grade inflammation is associated with several adult-onset diseases. However, the effects of visceral adipose tissue inflammation on the normal and ischemic brains of aged are not clearly defined. To examine the role of visceral adipose tissue inflammation, we evaluated inflammatory cytokines in the serum, visceral adipose tissue, and brain as well as blood-brain barrier (BBB) permeability in aged male mice (20 months) underwent sham or visceral fat removal surgery compared with the young mice (2.5 months). Additionally, ischemic brain injury was compared in young and aged mice with sham and visceral fat removal surgery. Interleukin (IL)-1β, IL-6, and tumor necrosis factor-α levels in examined organs were increased in aged mice compared with the young mice, and these levels were reduced in the mice with visceral fat removal. Increased BBB permeability with reduced expression of tight junction proteins in aged sham mice were also decreased in mice with visceral fat removal. After focal ischemic injury, aged mice with visceral fat removal showed a reduction in infarct volumes, BBB permeability, and levels of proinflammatory cytokines in the ischemic brain compared with sham mice, although the neurological outcomes were not significantly improved. In addition, further upregulated visceral adipose tissue inflammation in response to ischemic brain injury was attenuated in mice with visceral fat removal. These results suggest that visceral adipose tissue inflammation is associated with age-related changes in the brain and contributes to the ischemic brain damage in the aged mice. We suggest that visceral adiposity should be considered as a factor affecting brain health and ischemic brain damage in the aged population. PMID:26184082

  4. Visceral adipose tissue inflammation is associated with age-related brain changes and ischemic brain damage in aged mice.

    Science.gov (United States)

    Shin, Jin A; Jeong, Sae Im; Kim, Minsuk; Yoon, Joo Chun; Kim, Hee-Sun; Park, Eun-Mi

    2015-11-01

    Visceral adipose tissue is accumulated with aging. An increase in visceral fat accompanied by low-grade inflammation is associated with several adult-onset diseases. However, the effects of visceral adipose tissue inflammation on the normal and ischemic brains of aged are not clearly defined. To examine the role of visceral adipose tissue inflammation, we evaluated inflammatory cytokines in the serum, visceral adipose tissue, and brain as well as blood-brain barrier (BBB) permeability in aged male mice (20 months) underwent sham or visceral fat removal surgery compared with the young mice (2.5 months). Additionally, ischemic brain injury was compared in young and aged mice with sham and visceral fat removal surgery. Interleukin (IL)-1β, IL-6, and tumor necrosis factor-α levels in examined organs were increased in aged mice compared with the young mice, and these levels were reduced in the mice with visceral fat removal. Increased BBB permeability with reduced expression of tight junction proteins in aged sham mice were also decreased in mice with visceral fat removal. After focal ischemic injury, aged mice with visceral fat removal showed a reduction in infarct volumes, BBB permeability, and levels of proinflammatory cytokines in the ischemic brain compared with sham mice, although the neurological outcomes were not significantly improved. In addition, further upregulated visceral adipose tissue inflammation in response to ischemic brain injury was attenuated in mice with visceral fat removal. These results suggest that visceral adipose tissue inflammation is associated with age-related changes in the brain and contributes to the ischemic brain damage in the aged mice. We suggest that visceral adiposity should be considered as a factor affecting brain health and ischemic brain damage in the aged population.

  5. Age-related changes in chest geometry during cardiopulmonary resuscitation.

    Science.gov (United States)

    Dean, J M; Koehler, R C; Schleien, C L; Michael, J R; Chantarojanasiri, T; Rogers, M C; Traystman, R J

    1987-06-01

    We studied alterations of chest geometry during conventional cardiopulmonary resuscitation in anesthetized immature swine. Pulsatile force was applied to the sternum in increments to determine the effects of increasing compression on chest geometry and intrathoracic vascular pressures. In 2-wk- and 1-mo-old piglets, permanent changes in chest shape developed due to incomplete recoil of the chest along the anteroposterior axis, and large intrathoracic vascular pressures were generated. In 3-mo-old animals, permanent chest deformity did not develop, and large intrathoracic vascular pressures were not produced. We propose a theoretical model of the chest as an elliptic cylinder. Pulsatile displacement along the minor axis of an ellipse produces a greater decrease in cross-sectional area than displacement of a circular cross section. As thoracic cross section became less circular due to deformity, greater changes in thoracic volume, and hence pressure, were produced. With extreme deformity at high force, pulsatile displacement became limited, diminishing pressure generation. We conclude that changes in chest geometry are important in producing intrathoracic intravascular pressure during conventional cardiopulmonary resuscitation in piglets. PMID:3610916

  6. Structural response of phyllomanganates to wet aging and aqueous Mn(II)

    Science.gov (United States)

    Hinkle, Margaret A. G.; Flynn, Elaine D.; Catalano, Jeffrey G.

    2016-11-01

    Naturally occurring Mn(IV/III) oxides are often formed through microbial Mn(II) oxidation, resulting in reactive phyllomanganates with varying Mn(IV), Mn(III), and vacancy contents. Residual aqueous Mn(II) may adsorb in the interlayer of phyllomanganates above vacancies in their octahedral sheets. The potential for interlayer Mn(II)-layer Mn(IV) comproportionation reactions and subsequent formation of structural Mn(III) suggests that aqueous Mn(II) may cause phyllomanganate structural changes that alters mineral reactivity or trace metal scavenging. Here we examine the effects of aging phyllomanganates with varying initial vacancy and Mn(III) content in the presence and absence of dissolved Mn(II) at pH 4 and 7. Three phyllomanganates were studied: two exhibiting turbostratic layer stacking (δ-MnO2 with high vacancy content and hexagonal birnessite with both vacancies and Mn(III) substitutions) and one with rotationally ordered layer stacking (triclinic birnessite containing predominantly Mn(III) substitutions). Structural analyses suggest that during aging at pH 4, Mn(II) adsorbs above vacancies and promotes the formation of phyllomanganates with rotationally ordered sheets and mixed symmetries arranged into supercells, while structural Mn(III) undergoes disproportionation. These structural changes at pH 4 correlate with reduced Mn(II) uptake onto triclinic and hexagonal birnessite after 25 days relative to 48 h of reaction, indicating that phyllomanganate reactivity decreases upon aging with Mn(II), or that recrystallization processes involving Mn(II) uptake occur over 25 days. At pH 7, Mn(II) adsorbs and causes limited structural effects, primarily increasing sheet stacking in δ-MnO2. These results show that aging-induced structural changes in phyllomanganates are affected by aqueous Mn(II), pH, and initial solid-phase Mn(III) content. Such restructuring likely alters manganese oxide reactions with other constituents in environmental and geologic systems

  7. Training-induced brain structure changes in the elderly.

    Science.gov (United States)

    Boyke, Janina; Driemeyer, Joenna; Gaser, Christian; Büchel, Christian; May, Arne

    2008-07-01

    It has been suggested that learning is associated with a transient and highly selective increase in brain gray matter in healthy young volunteers. It is not clear whether and to what extent the aging brain is still able to exhibit such structural plasticity. We built on our original study, now focusing on healthy senior citizens. We observed that elderly persons were able to learn three-ball cascade juggling, but with less proficiency compared with 20-year-old adolescents. Similar to the young group, gray-matter changes in the older brain related to skill acquisition were observed in area hMT/V5 (middle temporal area of the visual cortex). In addition, elderly volunteers who learned to juggle showed transient increases in gray matter in the hippocampus on the left side and in the nucleus accumbens bilaterally. PMID:18614670

  8. Changes in social relations in old age. Are they influenced by functional ability?

    DEFF Research Database (Denmark)

    Avlund, Kirsten; Due, Pernille; Holstein, Bjorn E;

    2002-01-01

    The aims of this article were to describe changes in social relations from ages 75 to 80, and analyze whether changes in social relations are influenced by functional ability at age 75. The study includes data from the NORA follow-up study of 75-80 year-old men and women in Jyväskylä (Finland...... for help in Physical Activities of Daily Living (PADL). Depressive symptoms, living alone and locality were included as covariates in the multivariate analyses. There were large changes in social relations in old age, but the changes included widely varying patterns of losses and gains among...

  9. The Developing, Aging Neocortex: How genetics and epigenetics influence early developmental patterning and age-related change.

    Directory of Open Access Journals (Sweden)

    Kelly J. Huffman

    2012-10-01

    Full Text Available A hallmark of mammalian development is the generation of functional subdivisions within the nervous system. In humans, this regionalization creates a complex system that regulates behavior, cognition, memory and emotion. During development, specification of neocortical tissue that leads to functional sensory and motor regions results from an interplay between cortically intrinsic, molecular processes, such as gene expression, and extrinsic processes regulated by sensory input. Cortical specification in mice occurs pre- and perinatally, when gene expression is robust and various anatomical distinctions are observed alongside an emergence of physiological function. After patterning, gene expression continues to shift and axonal connections mature into an adult form. The function of adult cortical gene expression may be to maintain neocortical subdivisions that were established during early patterning. As some changes in neocortical gene expression have been observed past early development into late adulthood, gene expression may also play a role in the altered neocortical function observed in age-related cognitive decline and brain dysfunction. This review provides a discussion of how neocortical gene expression and specific patterns of neocortical sensori-motor axonal connections develop and change throughout the lifespan of the animal. We posit that a role of neocortical gene expression in neocortex is to regulate plasticity mechanisms that impact critical periods for sensory and motor plasticity in aging. We describe results from several studies in aging brain that detail changes in gene expression that may relate to microstructural changes observed in brain anatomy. We discuss the role of altered glucocorticoid signaling in age-related cognitive and functional decline, as well as how aging in the brain may result from immune system activation. We describe how caloric restriction or reduction of oxidative stress may ameliorate effects of aging

  10. Mollified birth in natural-age-grid Galerkin methods for age-structured biological systems

    International Nuclear Information System (INIS)

    We present natural-age-grid Galerkin methods for a model of a biological population undergoing aging. We use a mollified birth term in the method and analysis. The error due to mollification is of arbitrary order, depending on the choice of mollifier. The methods in this paper generalize the methods presented in [1], where the approximation space in age was taken to be a discontinuous piecewise polynomial subspace of L2. We refer to these methods as 'natural-age-grid' Galerkin methods since transport in the age variable is computed through the smooth movement of the age grid at the natural dimensionless velocity of one. The time variable has been left continuous to emphasize this smooth motion, as well as the independence of the time and age discretizations. The methods are shown to be superconvergent in the age variable

  11. Structural changes in amber due to uranium mineralization.

    Science.gov (United States)

    Havelcová, Martina; Machovič, Vladimír; Mizera, Jiří; Sýkorová, Ivana; René, Miloš; Borecká, Lenka; Lapčák, Ladislav; Bičáková, Olga; Janeček, Oldřich; Dvořák, Zdeněk

    2016-07-01

    The presence of uranium, with a bulk mass fraction of about 1.5 wt% and radiolytic alterations are a feature of Cenomanian amber from Křižany, at the northeastern edge of the North Bohemian Cretaceous uranium ore district. Pores and microcracks in the amber were filled with a mineral admixture, mainly in the form of Zr-Y-REE enriched uraninite. As a result of radiolytic alterations due to the presence of uranium, structural changes were observed in the Křižany amber in comparison with a reference amber from Nové Strašecí in central Bohemia; this was of similar age and botanical origin but did not contain elevated levels of uranium. Structural changes involved an increase in aromaticity due to dehydroaromatization of aliphatic cyclic hydrocarbons, loss of oxygen functional groups, an increase in the degree of polymerization, crosslinking of CC bonds, formation of a three-dimensional hydrocarbon network in the bulk organic matrix, and carbonization of the organic matrix around the uraninite infill. PMID:27085038

  12. Computed tomography structural lung changes in discordant airflow limitation.

    Directory of Open Access Journals (Sweden)

    Firdaus A A Mohamed Hoesein

    Full Text Available BACKGROUND: There is increasing evidence that structural lung changes may be present before the occurrence of airflow limitation as assessed by spirometry. This study investigated the prevalence of computed tomography (CT quantified emphysema, airway wall thickening and gas trapping according to classification of airflow limitation (FEV1/FVC 70%; group 2LLN; and group 370% but FEV1 <80% predicted, were excluded. Multivariate regression analysis correcting for covariates was used to asses the extent of emphysema, airway wall thickening and gas trapping according to three groups of airflow limitation. RESULTS: Mean (standard deviation age was 62.5 (5.2 years and packyears smoked was 41.0 (18.0. Group 2 subjects when compared to group 1 had a significantly lower 15(th percentile, -920.6 HU versus -912.2 HU; a higher Pi10, 2.87 mm versus 2.57 mm; and a higher E/I-ratio, 88.6% versus 85.6% (all p<0.001. CONCLUSION: Subjects with an FEV1/FVC<70%, but above the LLN, have a significant greater degree of structural lung changes on CT compared to subjects without airflow limitation.

  13. [Age-dependent changes in mRNA transport (nucleus-cytoplasm)].

    Science.gov (United States)

    Müller, W E; Agutter, P S; Prochnow, D J; Fasold, H; Sève, A P; Tsiapalis, C M; Schröder, H C

    1993-01-01

    Transport of mRNA from nucleus to cytoplasm is an ATP-dependent process which occurs strictly vectorially. Because the mRNA is structurally bound during transport, mRNA transport is a "solid-state" process consisting of i) mRNA release from the nuclear matrix, ii) mRNA translocation through the nuclear pore, and iii) cytoskeletal binding. We identified and purified the following components involved in the translocation step: i) the nuclear envelope (NE) nucleoside triphosphatase (NTPase) which is stimulated by the 3'poly(A) tail of mRNA, ii) the poly(A)-recognizing mRNA carrier, iii) the NE protein kinase, and iv) the NE phosphatase. In addition, we found that an RNA helicase activity is present in NE, which also may be involved in RNA transport. Our results show that, besides poly(A), also double-stranded RNA structures may modulate RNA export. The amount of mRNA released from nuclei markedly decreases with age. Evidence is presented that this age-dependent change is caused by an impairment of polyadenylation of mRNA, hnRNA processing, release of mRNA from nuclear matrix, and translocations of mRNA from nuclear to cytoplasmic compartment (decrease in activities of NE NTPase, protein kinase, and phosphatase; decrease in poly(A)-binding affinity of mRNA carrier).

  14. Changing Structures; Changing Rules: The Development of the "Internal Market."

    Science.gov (United States)

    Penney, D.; Evans, J.

    1995-01-01

    Explores the 1988 Education Reform Act's effects on providing physical education and sports in British schools, and specifically, implementation of the National Curriculum for Physical Education. The ERA and local school management have not only changed interschool and school-government agency relationships, but have fostered potentially damaging…

  15. The Political Structure of Cilicia in Iron Age

    Directory of Open Access Journals (Sweden)

    Mehmet KURT

    2009-06-01

    Full Text Available The plains of Cilicia (Çukurova, which was called Que by the Assyrians, is mentioned as Hume in the Neo-Babylonian sources. The equivalent of Hilakku, which is used for all of the Mountainous Cilicia or at least a part of it n the Assyrian sources, is Pirindu in the Neo-Babylonian texts. Cilicia, consisting of two different regions with completely opposite features; has a geographical dversity with its mountains, rivers, plains and straits. Both the local inscriptions as well as the Assyrian and Neo-Babylonian texts have shown that the geographical diversity had brought a political diversity, too. Thus, an administrational structure with a multiplicity in the local powers and a hierarchy in the political problems was prevalent in the region during the whole Iron Age. Starting from the Neo-Assyrian State, this political organisation, which was provided through the small local kingdoms that were the vassals of the big kingdoms had been applied without any interruption until the occupation of the Macedonian King Alexander the Great.

  16. Sensitivity analysis of the age-structured malaria transmission model

    Science.gov (United States)

    Addawe, Joel M.; Lope, Jose Ernie C.

    2012-09-01

    We propose an age-structured malaria transmission model and perform sensitivity analyses to determine the relative importance of model parameters to disease transmission. We subdivide the human population into two: preschool humans (below 5 years) and the rest of the human population (above 5 years). We then consider two sets of baseline parameters, one for areas of high transmission and the other for areas of low transmission. We compute the sensitivity indices of the reproductive number and the endemic equilibrium point with respect to the two sets of baseline parameters. Our simulations reveal that in areas of either high or low transmission, the reproductive number is most sensitive to the number of bites by a female mosquito on the rest of the human population. For areas of low transmission, we find that the equilibrium proportion of infectious pre-school humans is most sensitive to the number of bites by a female mosquito. For the rest of the human population it is most sensitive to the rate of acquiring temporary immunity. In areas of high transmission, the equilibrium proportion of infectious pre-school humans and the rest of the human population are both most sensitive to the birth rate of humans. This suggests that strategies that target the mosquito biting rate on pre-school humans and those that shortens the time in acquiring immunity can be successful in preventing the spread of malaria.

  17. Thermally induced structural changes in Nomex fibres

    Indian Academy of Sciences (India)

    Anjana Jain; Kalyani Vijayan

    2002-08-01

    Thermally aged Nomex fibres manifest several residual effects viz. reduction in X-ray crystallinity, weight loss and deterioration in tensile characteristics. Surface damages in the form of longitudinal openings, holes, material deposits etc have also been observed. Based on the data from thermally exposed fibres, the time needed for states of zero tensile strength and modulus have been predicted.

  18. Arctic security in an age of climate change

    Energy Technology Data Exchange (ETDEWEB)

    Kraska, James (ed.)

    2013-03-01

    Publisher review: This book examines Arctic defense policy and military security from the perspective of all eight Arctic states. In light of climate change and melting ice in the Arctic Ocean, Canada, Russia, Denmark (Greenland), Norway and the United States, as well as Iceland, Sweden and Finland, are grappling with an emerging Arctic security paradigm. This volume brings together the world's most seasoned Arctic political-military experts from Europe and North America to analyze how Arctic nations are adapting their security postures to accommodate increased shipping, expanding naval presence, and energy and mineral development in the polar region. The book analyzes the ascent of Russia as the first 'Arctic superpower', the growing importance of polar security for NATO and the Nordic states, and the increasing role of Canada and the United States in the region.(Author)

  19. Age-dependent changes in innate immune phenotype and function in rhesus macaques (Macaca mulatta

    Directory of Open Access Journals (Sweden)

    Mark Asquith

    2012-06-01

    Full Text Available Aged individuals are more susceptible to infections due to a general decline in immune function broadly referred to as immune senescence. While age-related changes in the adaptive immune system are well documented, aging of the innate immune system remains less well understood, particularly in nonhuman primates. A more robust understanding of age-related changes in innate immune function would provide mechanistic insight into the increased susceptibility of the elderly to infection. Rhesus macaques have proved a critical translational model for aging research, and present a unique opportunity to dissect age-dependent modulation of the innate immune system. We examined age-related changes in: (i innate immune cell frequencies; (ii expression of pattern recognition receptors (PRRs and innate signaling molecules; (iii cytokine responses of monocytes and dendritic cells (DC following stimulation with PRR agonists; and (iv plasma cytokine levels in this model. We found marked changes in both the phenotype and function of innate immune cells. This included an age-associated increased frequency of myeloid DC (mDC. Moreover, we found toll-like receptor (TLR agonists lipopolysaccharide (TLR4, fibroblast stimulating ligand-1 (TLR2/6, and ODN2006 (TLR7/9 induced reduced cytokine responses in aged mDC. Interestingly, with the exception of the monocyte-derived TNFα response to LPS, which increased with age, TNFα, IL-6, and IFNα responses declined with age. We also found that TLR4, TLR5, and innate negative regulator, sterile alpha and TIR motif containing protein (SARM, were all expressed at lower levels in young animals. By contrast, absent in melanoma 2 and retinoic acid-inducible gene I expression was lowest in aged animals. Together, these observations indicate that several parameters of innate immunity are significantly modulated by age and contribute to differential immune function in aged macaques.

  20. Estimation of age structure of fish populations from length-frequency data

    International Nuclear Information System (INIS)

    A probability model is presented to determine the age structure of a fish population from length-frequency data. It is shown that when the age-length key is available, maximum-likelihood estimates of the age structure can be obtained. When the key is not available, approximate estimates of the age structure can be obtained. The model is used for determination of the age structure of populations of channel catfish and white crappie. Practical applications of the model to impact assessment are discussed

  1. Age-related molecular genetic changes of murine bone marrow mesenchymal stem cells

    Directory of Open Access Journals (Sweden)

    Webster Keith A

    2010-04-01

    Full Text Available Abstract Background Mesenchymal stem cells (MSC are pluripotent cells, present in the bone marrow and other tissues that can differentiate into cells of all germ layers and may be involved in tissue maintenance and repair in adult organisms. Because of their plasticity and accessibility these cells are also prime candidates for regenerative medicine. The contribution of stem cell aging to organismal aging is under debate and one theory is that reparative processes deteriorate as a consequence of stem cell aging and/or decrease in number. Age has been linked with changes in osteogenic and adipogenic potential of MSCs. Results Here we report on changes in global gene expression of cultured MSCs isolated from the bone marrow of mice at ages 2, 8, and 26-months. Microarray analyses revealed significant changes in the expression of more than 8000 genes with stage-specific changes of multiple differentiation, cell cycle and growth factor genes. Key markers of adipogenesis including lipoprotein lipase, FABP4, and Itm2a displayed age-dependent declines. Expression of the master cell cycle regulators p53 and p21 and growth factors HGF and VEGF also declined significantly at 26 months. These changes were evident despite multiple cell divisions in vitro after bone marrow isolation. Conclusions The results suggest that MSCs are subject to molecular genetic changes during aging that are conserved during passage in culture. These changes may affect the physiological functions and the potential of autologous MSCs for stem cell therapy.

  2. The Vintage Effect in TPF-Growth : An Analysis of the Age Structure of Capital

    NARCIS (Netherlands)

    Gittleman, M.; Ten Raa, T.; Wolff, E.N.

    2003-01-01

    The age structure of capital plays an important role in the measurement of productivity.It has been argued that the slowdown in the 1970 s can be ascribed to the aging of the stock of capital.In this paper we incorporate the age structure in productivity measurement.One proposition proves that Nelso

  3. Ecological Changes in Coyotes (Canis latrans) in Response to the Ice Age Megafaunal Extinctions

    OpenAIRE

    Meachen, Julie A.; Adrianna C Janowicz; Jori E Avery; Rudyard W Sadleir

    2014-01-01

    Coyotes (Canis latrans) are an important species in human-inhabited areas. They control pests and are the apex predators in many ecosystems. Because of their importance it is imperative to understand how environmental change will affect this species. The end of the Pleistocene Ice Age brought with it many ecological changes for coyotes and here we statistically determine the changes that occurred in coyotes, when these changes occurred, and what the ecological consequences were of these chang...

  4. TOURISM'S CHANGING FACE: NEW AGE TOURISM VERSUS OLD TOURISM

    Directory of Open Access Journals (Sweden)

    Molnar Elisabeta

    2011-07-01

    Full Text Available Abstract: Times are changing and so are the demands and expectations of the 'new' traveller, the search for different experiences, different adventures, different lifestyles has paved the way for this concept called the 'new tourism' Attention is being turned to exploring new frontiers or daring to go where traditional thought did not allow. "New" tourists however, are increasingly being seen to be environmentally sensitive, displaying respect for the culture of host nations and looking to experience and learn rather than merely stand back and gaze. "New" tourists are participators not spectators. Things that would never appear on the list of the "mass" tourist such as adventure, getting of the beaten track and mingling with the locals are now the foundations of the new tourist experiences. Responding to the shift in market dynamics towards a "New" style of tourist, a number of initiatives have or are likely to fuel the growth of experiential tourism, these include: network tourism initiatives; the development of interpretive highways; the explosion of interpretive centers;the latest trend towards regional base camps. A new era has arrived, and a new kind of tourism is emerging, sustainable, environmentally and socially responsible, and characterized by flexibility and choice. A new type of tourist is driving it: more educated, experienced, independent, conservation-minded, respectful of cultures, and insistent on value for money. Typically these tourists are turning away from travel and prefer to have a high level of involvement in the organisation of their trip.

  5. Age of Onset of Schizophrenia: Perspectives From Structural Neuroimaging Studies

    OpenAIRE

    Gogtay, Nitin; Nora S Vyas; Testa, Renee; Wood, Stephen J.; Pantelis, Christos

    2011-01-01

    Many of the major neuropsychiatric illnesses, including schizophrenia, have a typical age of onset in late adolescence. Late adolescence may reflect a critical period in brain development making it particularly vulnerable for the onset of psychopathology. Neuroimaging studies that focus on this age range may provide unique insights into the onset and course of psychosis. In this review, we examine the evidence from 2 unique longitudinal cohorts that span the ages from early childhood through ...

  6. Relative Energy Dissipation: Sensitive to Structural Changes of Liquids

    Institute of Scientific and Technical Information of China (English)

    祖方遒; 郭丽君; 朱震刚; 凤仪

    2002-01-01

    Energy dissipation techniques, widely used in solid physics previously, are proven to be sensitive also to changes in liquid structure. It has been suggested from relative energy dissipation that changes in liquid structure can occur as a function of temperature in some ordinary binary systems such as Pb-Sn, In-Sn and In-Bi. This finding may be helpful to understand liquid structure changing patterns, therefore enriching the phenomenology of liquid state physics. This is significant for engineering practices.

  7. Changes in the educational structure of the population of Vojvodina

    Directory of Open Access Journals (Sweden)

    Markov Slobodanka

    2007-01-01

    Full Text Available This paper will consider the changes in the educational structure of the Vojvodina population during the second half of the 20th century. The analysis, based on the 1953, 1981 and 2002 census data, takes into account the degree of illiteracy, structure according to level of education, as well as regional, gender and generational aspects of the above-mentioned changes. The basic finding is that, with the expansion of the network of educational institutions, there was a fast and significant increase in the number of people with occupational and professional education, accompanied by a slower decrease in the number of illiterate people as well as people with incomplete elementary education. The outcome of these changes is that in Vojvodina according to the results of the 2002 census, the most numerous category is that of people with the secondary education - 44% of the population over the age of 15 compared to 8.29% in 1953 - while the percentage of people with the higher and university education was 9.52% compared 0.55% in 1953, which is a significant civilisational effect of a half century development of education. However, the 20% of people with incomplete or without elementary school along with the 25% of people with elementary school education, make up the other half of the population without any qualifications. Gender inequalities have been radically decreased in the whole range from elementary to the highest level of education, whereas generational differences have also constantly decreased, while significant differences remain mainly between the oldest and youngest generations.

  8. Elderly and sun-affected skin. Distinguishing between changes caused by aging and changes caused by habitual exposure to sun.

    OpenAIRE

    2001-01-01

    OBJECTIVE: To review and distinguish between skin changes produced by aging and changes produced by habitual exposure to sun. QUALITY OF EVIDENCE: The literature was searched from 1969 to 1999 for articles on dermatoheliosis and sun-damaged skin. Surprisingly few were found comparing the difference between elderly skin and sun-damaged skin. A few articles focused on certain small aspects of sun-damaged skin. Many excellent articles described particular changes (e.g., actinic keratosis), but f...

  9. Genome-wide age-related changes in DNA methylation and gene expression in human PBMCs.

    Science.gov (United States)

    Steegenga, Wilma T; Boekschoten, Mark V; Lute, Carolien; Hooiveld, Guido J; de Groot, Philip J; Morris, Tiffany J; Teschendorff, Andrew E; Butcher, Lee M; Beck, Stephan; Müller, Michael

    2014-06-01

    Aging is a progressive process that results in the accumulation of intra- and extracellular alterations that in turn contribute to a reduction in health. Age-related changes in DNA methylation have been reported before and may be responsible for aging-induced changes in gene expression, although a causal relationship has yet to be shown. Using genome-wide assays, we analyzed age-induced changes in DNA methylation and their effect on gene expression with and without transient induction with the synthetic transcription modulating agent WY14,643. To demonstrate feasibility of the approach, we isolated peripheral blood mononucleated cells (PBMCs) from five young and five old healthy male volunteers and cultured them with or without WY14,643. Infinium 450K BeadChip and Affymetrix Human Gene 1.1 ST expression array analysis revealed significant differential methylation of at least 5 % (ΔYO > 5 %) at 10,625 CpG sites between young and old subjects, but only a subset of the associated genes were also differentially expressed. Age-related differential methylation of previously reported epigenetic biomarkers of aging including ELOVL2, FHL2, PENK, and KLF14 was confirmed in our study, but these genes did not display an age-related change in gene expression in PBMCs. Bioinformatic analysis revealed that differentially methylated genes that lack an age-related expression change predominantly represent genes involved in carcinogenesis and developmental processes, and expression of most of these genes were silenced in PBMCs. No changes in DNA methylation were found in genes displaying transiently induced changes in gene expression. In conclusion, aging-induced differential methylation often targets developmental genes and occurs mostly without change in gene expression.

  10. Genome-wide age-related changes in DNA methylation and gene expression in human PBMCs.

    Science.gov (United States)

    Steegenga, Wilma T; Boekschoten, Mark V; Lute, Carolien; Hooiveld, Guido J; de Groot, Philip J; Morris, Tiffany J; Teschendorff, Andrew E; Butcher, Lee M; Beck, Stephan; Müller, Michael

    2014-06-01

    Aging is a progressive process that results in the accumulation of intra- and extracellular alterations that in turn contribute to a reduction in health. Age-related changes in DNA methylation have been reported before and may be responsible for aging-induced changes in gene expression, although a causal relationship has yet to be shown. Using genome-wide assays, we analyzed age-induced changes in DNA methylation and their effect on gene expression with and without transient induction with the synthetic transcription modulating agent WY14,643. To demonstrate feasibility of the approach, we isolated peripheral blood mononucleated cells (PBMCs) from five young and five old healthy male volunteers and cultured them with or without WY14,643. Infinium 450K BeadChip and Affymetrix Human Gene 1.1 ST expression array analysis revealed significant differential methylation of at least 5 % (ΔYO > 5 %) at 10,625 CpG sites between young and old subjects, but only a subset of the associated genes were also differentially expressed. Age-related differential methylation of previously reported epigenetic biomarkers of aging including ELOVL2, FHL2, PENK, and KLF14 was confirmed in our study, but these genes did not display an age-related change in gene expression in PBMCs. Bioinformatic analysis revealed that differentially methylated genes that lack an age-related expression change predominantly represent genes involved in carcinogenesis and developmental processes, and expression of most of these genes were silenced in PBMCs. No changes in DNA methylation were found in genes displaying transiently induced changes in gene expression. In conclusion, aging-induced differential methylation often targets developmental genes and occurs mostly without change in gene expression. PMID:24789080

  11. Using the gradient of human cortical bone properties to determine age-related bone changes via ultrasonic guided waves.

    Science.gov (United States)

    Baron, Cécile

    2012-06-01

    Bone fragility depends not only on bone mass but also on bone quality (structure and material). To accurately evaluate fracture risk or propose therapeutic treatment, clinicians need a criterion, which reflects the determinants of bone strength: geometry, structure and material. In human long bone, the changes due to aging, accentuated by osteoporosis are often revealed through the trabecularization of cortical bone, i.e., increased porosity of endosteal bone inducing a thinning of the cortex. Consequently, the intracortical porosity gradient corresponding to the spatial variation in porosity across the cortical thickness is representative of loss of mass, changes in geometry (thinning) and variations in structure (porosity). This article examines the gradient of material properties and its age-related evolution as a relevant parameter to assess bone geometry, structure and material. By applying a homogenization process, cortical bone can be considered as an anisotropic functionally graded material with variations in material properties. A semi-analytical method based on the sextic Stroh formalism is proposed to solve the wave equation in an anisotropic functionally graded waveguide for two geometries, a plate and a tube, without using a multilayered model to represent the structure. This method provides an analytical solution called the matricant and explicitly expressed under the Peano series expansion form. Our findings indicate that ultrasonic guided waves are sensitive to the age-related evolution of realistic gradients in human bone properties across the cortical thickness and have their place in a multimodal clinical protocol. PMID:22502890

  12. Age Differences in Personality Structure: A Cluster Analytic Approach

    Science.gov (United States)

    Costa, Paul T., Jr.; McCrae, Robert R.

    1976-01-01

    Presented at the 81st APA Convention, Montreal, 1973, this study showed how a cluster analytic approach was used to determine age differences in personality measured by the Sixteen Personality Factor Questionnaire (16PF). Subjects were 969 adult male volunteers, 25 to 34, 35 to 54, and 55 to 82. Openness to experience showed age-related…

  13. Morphological Changes in the Suprachiasmatic Nucleus of Aging Female Marmosets (Callithrix jacchus

    Directory of Open Access Journals (Sweden)

    Rovena Clara G. J. Engelberth

    2014-01-01

    Full Text Available The suprachiasmatic nuclei (SCN are pointed to as the mammals central circadian pacemaker. Aged animals show internal time disruption possibly caused by morphological and neurochemical changes in SCN components. Some studies reported changes of neuronal cells and neuroglia in the SCN of rats and nonhuman primates during aging. The effects of senescence on morphological aspects in SCN are important for understanding some alterations in biological rhythms expression. Therefore, our aim was to perform a comparative study of the morphological aspects of SCN in adult and aged female marmoset. Morphometric analysis of SCN was performed using Nissl staining, NeuN-IR, GFAP-IR, and CB-IR. A significant decrease in the SCN cells staining with Nissl, NeuN, and CB were observed in aged female marmosets compared to adults, while a significant increase in glial cells was found in aged marmosets, thus suggesting compensatory process due to neuronal loss evoked by aging.

  14. Age-related changes in the macula. A histopathological study of fifty Indian donor eyes

    Directory of Open Access Journals (Sweden)

    Biswas Jyotirmay

    2002-01-01

    Full Text Available PURPOSE: Age-related macular degeneration (ARMD is clinically less common in India compared to the West. Therefore, clinicians are unfamiliar with histopathologic evidence of age-related macular changes in the Indian population. METHODS: Fifty consecutive human donor eyes removed for corneal grafting were studied for gross, microscopic and histochemical features of age-related changes in the macula in the Indian population. A horizontal block was cut from the globe including the optic disc, and the macula. Six sections, 6 microns thick, were cut from three levels in the macula at a distance of 140 microns. These were stained with haemotoxylin-eosin, periodic acid-Schiff, Mallory, Masson trichrome, alcian blue and von Kossa stains. The presence of basal laminar deposits, drusen and thickening and calcification of Bruch′s membrane in the macula were assessed at 400 x magnification using a modified version of Sark′s classification. RESULTS: Twenty-four donor eyes (48% had some form of age-related macular change. These included basal laminar deposits, hard drusen, soft drusen, extensive retinal pigment epithelium atrophy of the macula, and disciform degeneration of macula. A combination of changes was often seen. Age-related changes were more common in the seventh and eighth decade. CONCLUSION: Our study shows that histological changes characteristic of the early stages of age-related macular degeneration are fairly common in the Indian population. However, advanced macular changes are significantly rare.

  15. Age-related changes in AMP-activated protein kinase after stroke

    OpenAIRE

    Liu, Fudong; Benashski, Sharon E; Persky, Rebecca; Xu, Yan; Li, Jun; McCullough, Louise D.

    2011-01-01

    Adenosine monophosphate-activated protein kinase (AMPK) is an evolutionary conserved energy sensor sensitive to changes in cellular AMP/ATP ratio which is activated by phosphorylation (pAMPK). pAMPK levels decrease in peripheral tissues with age, but whether this also occurs in the aged brain, and how this contributes to the ability of the aged brain to cope with ischemic stress is unknown. This study investigated the activation of AMPK and the response to AMPK inhibition after induced stroke...

  16. Correlation of cognitive performance and morphological changes in neocortical pyramidal neurons in aging

    OpenAIRE

    Allard, Simon; Scardochio, Tina; Cuello, A. Claudio; Ribeiro-da-Silva, Alfredo

    2010-01-01

    It is well established that the cerebral cortex undergoes extensive remodeling in aging. In this study, we used behaviorally characterized rats to correlate age-related morphological changes with cognitive impairment. For this, young and aged animals were tested in the Morris water maze to evaluate their cognitive performance. Following behavioral characterization, the animals were perfused and a combination of intracellular labeling and immunohistochemistry was applied. Using this approach, ...

  17. Upgrade and Design of Coastal Structures Exposed to Climate Changes

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Quvang Harck

    This thesis "Upgrade and Design of Coastal Structures Exposed to Climate Changes" evaluates the performance of existing types of structures when exposed to climate changes. This includes also the potential of using cost‐sharing multipurpose structures for protection against the effects of future...... climate changes. The thesis consists of three parts. The first part evaluates the performance of existing design formulae for estimation of wave actions on structures, especially in shallow water since these structures are most vulnerable to the rising sea water levels caused by climate changes. Existing...... of coastal protection structures, which are extended to a wider range of wave conditions, and which can be used to more accurately estimate the influence from climate changes. In the second part of the thesis, the extended and modified formulae are used in case studies to evaluate the influence from climate...

  18. Loss of muscle performance in seniors: changes to the dynamic muscle structure and muscle gearing

    OpenAIRE

    Randhawa, Avleen

    2012-01-01

    Muscle structure changes with ageing in a manner that can alter its contractile mechanics, resulting in a reduction in strength and mobility. Fascicles within a muscle can shorten at slower velocities than the muscle belly, in a process known as belly gearing. Belly gearing allows the fascicles to produce a greater force when they contract. However, it may be compromised when we age. The gastrocnemii muscles in the calf were imaged in young adults and seniors using ultrasound. Their muscle st...

  19. Structural change in OECD comparative advantage

    NARCIS (Netherlands)

    Brakman, Steven; Inklaar, Robert; Van Marrewijk, Charles

    2013-01-01

    In the post-war period, the goods composition of trade in Organisation for Economic Cooperation and Development (OECD) countries has changed considerably. We analyze the evolution of comparative advantage using a detailed trade data set and a new analytical tool: the Harmonic Mass index (HM index),

  20. Age-related changes in normal adult pancreas: MR imaging evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Tomohiro, E-mail: tomohiro@med.kawasaki-m.ac.jp [Department of Radiology, Kawasaki Medical School, Matsushima, Kurashiki City, Okayama, 701-0192 (Japan); Ito, Katsuyoshi, E-mail: itokatsu@med.kawasaki-m.ac.jp [Department of Radiology, Kawasaki Medical School, Matsushima, Kurashiki City, Okayama, 701-0192 (Japan); Tamada, Tsutomu, E-mail: ttamada@med.kawasaki-m.ac.jp [Department of Radiology, Kawasaki Medical School, Matsushima, Kurashiki City, Okayama, 701-0192 (Japan); Sone, Teruki, E-mail: tsone@med.kawasaki-m.ac.jp [Department of Radiology, Kawasaki Medical School, Matsushima, Kurashiki City, Okayama, 701-0192 (Japan); Noda, Yasufumi, E-mail: yasufumi@med.kawasaki-m.ac.jp [Department of Radiology, Kawasaki Medical School, Matsushima, Kurashiki City, Okayama, 701-0192 (Japan); Higaki, Atsushi, E-mail: ahah@med.kawasaki-m.ac.jp [Department of Radiology, Kawasaki Medical School, Matsushima, Kurashiki City, Okayama, 701-0192 (Japan); Kanki, Akihiko, E-mail: ponbon@med.kawasaki-m.ac.jp [Department of Radiology, Kawasaki Medical School, Matsushima, Kurashiki City, Okayama, 701-0192 (Japan); Tanimoto, Daigo, E-mail: daigoro@med.kawasaki-m.ac.jp [Department of Radiology, Kawasaki Medical School, Matsushima, Kurashiki City, Okayama, 701-0192 (Japan); Higashi, Hiroki, E-mail: higahiro@med.kawasaki-m.ac.jp [Department of Radiology, Kawasaki Medical School, Matsushima, Kurashiki City, Okayama, 701-0192 (Japan)

    2012-09-15

    Objective: To investigate age-related changes in normal adult pancreas as identified by magnetic resonance imaging (MRI). Materials and methods: We examined 115 patients without pancreatic diseases (21–90 years) who underwent upper abdominal MRI to evaluate the normal pancreatic MRI findings related to aging. The parameters examined were the pancreatic anteroposterior (AP) diameter, pancreatic lobulation, pancreatic signal intensity (SI), depiction of the main pancreatic duct (MPD), grade of the visual SI decrease on the opposed-phase T1-weighted images compared with in-phase images, and enhancement effect of the pancreas in the arterial phase of dynamic imaging. Results: The pancreatic AP diameter significantly reduced (head, p = 0.0172; body, p = 0.0007; tail, p < 0.0001), and lobulation (p < 0.0001) and parenchymal fatty change (p < 0.0001) became more evident with aging. No significant correlation was observed between aging and pancreatic SI, however the SI on the in-phase T1-weighted images tended to decrease with aging. No significant correlation was observed between aging and the depiction of the MPD as well as aging and contrast enhancement. Conclusion: MRI findings of pancreatic atrophy, lobulation, and fatty degeneration are characteristic changes related to aging, and it is necessary to recognize these changes in the interpretation of abdominal MRI in patients with and without pancreatic disease.

  1. Age-related changes in normal adult pancreas: MR imaging evaluation

    International Nuclear Information System (INIS)

    Objective: To investigate age-related changes in normal adult pancreas as identified by magnetic resonance imaging (MRI). Materials and methods: We examined 115 patients without pancreatic diseases (21–90 years) who underwent upper abdominal MRI to evaluate the normal pancreatic MRI findings related to aging. The parameters examined were the pancreatic anteroposterior (AP) diameter, pancreatic lobulation, pancreatic signal intensity (SI), depiction of the main pancreatic duct (MPD), grade of the visual SI decrease on the opposed-phase T1-weighted images compared with in-phase images, and enhancement effect of the pancreas in the arterial phase of dynamic imaging. Results: The pancreatic AP diameter significantly reduced (head, p = 0.0172; body, p = 0.0007; tail, p < 0.0001), and lobulation (p < 0.0001) and parenchymal fatty change (p < 0.0001) became more evident with aging. No significant correlation was observed between aging and pancreatic SI, however the SI on the in-phase T1-weighted images tended to decrease with aging. No significant correlation was observed between aging and the depiction of the MPD as well as aging and contrast enhancement. Conclusion: MRI findings of pancreatic atrophy, lobulation, and fatty degeneration are characteristic changes related to aging, and it is necessary to recognize these changes in the interpretation of abdominal MRI in patients with and without pancreatic disease

  2. Obesity and Age-Related Changes in Markers of Oxidative Stress and Inflammation Across Four Generations

    NARCIS (Netherlands)

    Hulsegge, Gerben; Herber-Gast, Gerrie-Cor M; Spijkerman, Annemieke M W; Susan, H; Picavet, J; van der Schouw, Yvonne T; Bakker, Stephan J L; Gansevoort, Ron T; Dollé, Martijn E T; Smit, Henriette A; Monique Verschuren, W M

    2016-01-01

    OBJECTIVE: The prevalence of obesity increases with age and is higher in each younger generation (unfavorable generation shift). This may influence patterns of oxidative stress and inflammation. Age-related changes and generation shifts in markers of oxidative stress and inflammation were investigat

  3. High Resolution Topography of Age-Related Changes in Non-Rapid Eye Movement Sleep Electroencephalography.

    Directory of Open Access Journals (Sweden)

    Kate E Sprecher

    Full Text Available Sleeping brain activity reflects brain anatomy and physiology. The aim of this study was to use high density (256 channel electroencephalography (EEG during sleep to characterize topographic changes in sleep EEG power across normal aging, with high spatial resolution. Sleep was evaluated in 92 healthy adults aged 18-65 years old using full polysomnography and high density EEG. After artifact removal, spectral power density was calculated for standard frequency bands for all channels, averaged across the NREM periods of the first 3 sleep cycles. To quantify topographic changes with age, maps were generated of the Pearson's coefficient of the correlation between power and age at each electrode. Significant correlations were determined by statistical non-parametric mapping. Absolute slow wave power declined significantly with increasing age across the entire scalp, whereas declines in theta and sigma power were significant only in frontal regions. Power in fast spindle frequencies declined significantly with increasing age frontally, whereas absolute power of slow spindle frequencies showed no significant change with age. When EEG power was normalized across the scalp, a left centro-parietal region showed significantly less age-related decline in power than the rest of the scalp. This partial preservation was particularly significant in the slow wave and sigma bands. The effect of age on sleep EEG varies substantially by region and frequency band. This non-uniformity should inform the design of future investigations of aging and sleep. This study provides normative data on the effect of age on sleep EEG topography, and provides a basis from which to explore the mechanisms of normal aging as well as neurodegenerative disorders for which age is a risk factor.

  4. High Resolution Topography of Age-Related Changes in Non-Rapid Eye Movement Sleep Electroencephalography.

    Science.gov (United States)

    Sprecher, Kate E; Riedner, Brady A; Smith, Richard F; Tononi, Giulio; Davidson, Richard J; Benca, Ruth M

    2016-01-01

    Sleeping brain activity reflects brain anatomy and physiology. The aim of this study was to use high density (256 channel) electroencephalography (EEG) during sleep to characterize topographic changes in sleep EEG power across normal aging, with high spatial resolution. Sleep was evaluated in 92 healthy adults aged 18-65 years old using full polysomnography and high density EEG. After artifact removal, spectral power density was calculated for standard frequency bands for all channels, averaged across the NREM periods of the first 3 sleep cycles. To quantify topographic changes with age, maps were generated of the Pearson's coefficient of the correlation between power and age at each electrode. Significant correlations were determined by statistical non-parametric mapping. Absolute slow wave power declined significantly with increasing age across the entire scalp, whereas declines in theta and sigma power were significant only in frontal regions. Power in fast spindle frequencies declined significantly with increasing age frontally, whereas absolute power of slow spindle frequencies showed no significant change with age. When EEG power was normalized across the scalp, a left centro-parietal region showed significantly less age-related decline in power than the rest of the scalp. This partial preservation was particularly significant in the slow wave and sigma bands. The effect of age on sleep EEG varies substantially by region and frequency band. This non-uniformity should inform the design of future investigations of aging and sleep. This study provides normative data on the effect of age on sleep EEG topography, and provides a basis from which to explore the mechanisms of normal aging as well as neurodegenerative disorders for which age is a risk factor.

  5. Age-related changes in the testes and prostate of the Beagle dog

    International Nuclear Information System (INIS)

    Age-related changes in the histologic morphology of the Beagle dog prostate and testes must be separated from those changes that may result from the testing of experimental compounds. The prostate and testes of healthy age-matched Beagle dogs 3 to 14 yr of age were obtained. Serum to evaluate testosterone levels was also obtained from each dog at the time of euthanasia. Tissue sections from the prostate and testes were examined by light microscopy for both qualitative and quantitative morphologic assessment. A statistically significant increase in prostatic weight with increased age was noted. Significant morphometric findings in the prostate included a decrease in the relative percent of epithelial cells and an increase in the relative lumen size of glandular acini with increased age. The absolute volume of prostate interstitial tissue and inflammation showed a statistically significant increase with age. Stereological analysis of the testes showed a decrease in the relative percent epithelium with increasing age. No distinct age-related trend could be detected in serum testosterone levels. Serum testosterone levels did not correlate with the morphologic age-related changes observed in the testes or prostate. (author)

  6. Morphological Changes in the Suprachiasmatic Nucleus of Aging Female Marmosets (Callithrix jacchus)

    OpenAIRE

    2014-01-01

    The suprachiasmatic nuclei (SCN) are pointed to as the mammals central circadian pacemaker. Aged animals show internal time disruption possibly caused by morphological and neurochemical changes in SCN components. Some studies reported changes of neuronal cells and neuroglia in the SCN of rats and nonhuman primates during aging. The effects of senescence on morphological aspects in SCN are important for understanding some alterations in biological rhythms expression. Therefore, our aim was to ...

  7. Developmental changes in facial expression recognition in Japanese school-age children

    OpenAIRE

    Naruse, Susumu; Hashimoto, Toshiaki; Mori, Kenji; TSUDA, Yoshimi; Takahara, Mitsue; Kagami, Shoji

    2013-01-01

    Purpose : Facial expressions hold abundant information and play a central part in communication. In daily life, we must construct amicable interpersonal relationships by communicating through verbal and nonverbal behaviors. While school-age is a period of rapid social growth, few studies exist that study developmental changes in facial expression recognition during this age. This study investigated developmental changes in facial expression recognition by examining observers’ gaze on others’ ...

  8. AED Treatment Through Different Ages: As Our Brains Change, Should Our Drug Choices Also?

    OpenAIRE

    French, Jacqueline A.; Staley, Brigid A.

    2012-01-01

    Patient age can impact selection of the optimal antiepileptic drug for a number of reasons. Changes in brain physiology from neonate to elderly, as well as changes in underlying etiologies of epilepsy, could potentially affect the ability of different drugs to control seizures. Unfortunately, much of this is speculative, as good studies demonstrating differences in efficacy across age ranges do not exist. Beyond the issue of efficacy, certain drugs may be more or less appropriate at different...

  9. Changes in soleus H-reflex during walking in middle-aged, healthy subjects

    DEFF Research Database (Denmark)

    Raffalt, Peter C; Alkjær, Tine; Simonsen, Erik B

    2015-01-01

    INTRODUCTION: To assess the effect of aging on stretch reflex modulation during walking, soleus H-reflexes obtained in 15 middle-aged (mean age 56.4±6.9 years) and 15 young (mean age 23.7±3.9 years) subjects were compared. METHODS: The H-reflex amplitude, muscle activity (EMG) of the soleus......-reflex amplitude during walking was affected by aging, and changes during the swing phase could be seen in the middle-aged subjects. Subdividing the 2 age groups into groups of facilitated or suppressed swing-phase H-reflex revealed that the H-reflex amplitude modulation pattern in the group with facilitated swing...

  10. Age-related compaction of lens fibers affects the structure and optical properties of rabbit lenses

    Directory of Open Access Journals (Sweden)

    Al-Ghoul Walid M

    2007-12-01

    Full Text Available Abstract Background The goal of this investigation was to correlate particular age-related structural changes (compaction to the amount of scatter in rabbit lenses and to determine if significant fiber compaction occurred in the nuclear and inner cortical regions. Methods New Zealand White rabbits at 16–20 months old (adult; n = 10 and at 3.5–4 years old (aged; n = 10 were utilized for this study. Immediately after euthanising, scatter was assessed in fresh lenses by low power helium-neon laser scan analysis. Scatter data was analyzed both for whole lenses and regionally, to facilitate correlation with morphometric data. After functional analysis, lenses were fixed and processed for scanning electron microcopy (SEM; right eyes and light microscopy (LM; left eyes. Morphometric analysis of SEM images was utilized to evaluate compaction of nuclear fibers. Similarly, measurements from LM images were used to assess compaction of inner cortical fibers. Results Scatter was significantly greater in aged lenses as compared to adult lenses in all regions analyzed, however the difference in the mean was slightly more pronounced in the inner cortical region. The anterior and posterior elliptical angles at 1 mm (inner fetal nucleus were significantly decreased in aged vs. adult lenses (anterior, p = 0.040; posterior, p = 0.036. However, the average elliptical angles at 2.5 mm (outer fetal nucleus were not significantly different in adult and aged lenses since all lenses examined had comparable angles to inner fetal fibers of aged lenses, i.e. they were all compacted. In cortical fibers, measures of average cross-sectional fiber area were significantly different at diameters of both 6 and 7 mm as a function of age (p = 0.011 and p = 0.005, respectively. Accordingly, the estimated fiber volume was significantly decreased in aged as compared to adult lenses at both 6 mm diameter (p = 0.016 and 7 mm diameter (p = 0.010. Conclusion Morphometric data indicates

  11. Voluntary wheel running reverses age-induced changes in hippocampal gene expression.

    Directory of Open Access Journals (Sweden)

    Rachel A Kohman

    Full Text Available Normal aging alters expression of numerous genes within the brain. Some of these transcription changes likely contribute to age-associated cognitive decline, reduced neural plasticity, and the higher incidence of neuropathology. Identifying factors that modulate brain aging is crucial for improving quality of life. One promising intervention to counteract negative effects of aging is aerobic exercise. Aged subjects that exercise show enhanced cognitive performance and increased hippocampal neurogenesis and synaptic plasticity. Currently, the mechanisms behind the anti-aging effects of exercise are not understood. The present study conducted a microarray on whole hippocampal samples from adult (3.5-month-old and aged (18-month-old male BALB/c mice that were individually housed with or without running wheels for 8 weeks. Results showed that aging altered genes related to chromatin remodeling, cell growth, immune activity, and synapse organization compared to adult mice. Exercise was found to modulate many of the genes altered by aging, but in the opposite direction. For example, wheel running increased expression of genes related to cell growth and attenuated expression of genes involved in immune function and chromatin remodeling. Collectively, findings show that even late-onset exercise may attenuate age-related changes in gene expression and identifies possible pathways through which exercise may exert its beneficial effects.

  12. Does foraging performance change with age in female little penguins (Eudyptula minor?

    Directory of Open Access Journals (Sweden)

    Ilka Zimmer

    Full Text Available Age-related changes in breeding performance are likely to be mediated through changes in parental foraging performance. We investigated the relationship of foraging performance with age in female little penguins at Phillip Island, Australia, during the guard phase of the 2005 breeding season. Foraging parameters were recorded with accelerometers for birds grouped into three age-classes: (1 young, (2 middle age and (3 old females. We found the diving behaviour of middle-aged birds differed from young and old birds. The dive duration of middle age females was shorter than that of young and old birds while their dive effort (measure for dive and post-dive duration relation was lower than that of young ones, suggesting middle-aged birds were in better physical condition than other ones. There was no difference in prey pursuit frequency or duration between age classes, but in the hunting tactic. Females pursued more prey around and after reaching the maximum depth of dives the more experienced they were (old > middle age > young, an energy saving hunting tactic by probably taking advantage of up-thrust momentum. We suggest middle age penguins forage better than young or old ones because good physical condition and foraging experience could act simultaneously.

  13. Age-dependent change in executive function and gamma 40 Hz phase synchrony.

    Science.gov (United States)

    Paul, Robert H; Clark, C Richard; Lawrence, Jeffrey; Goldberg, Elkhonon; Williams, Leanne M; Cooper, Nicholas; Cohen, Ronald A; Brickman, Adam M; Gordon, Evian

    2005-03-01

    Decline in cognitive function is well recognized, yet few neurophysiological correlates of age-related cognitive decline have been identified. In this study we examined the impact of age on neurocognitive function and Gamma phase synchrony among 550 normal subjects (aged 11-70). Gamma phase synchrony was acquired to targets in the auditory oddball paradigm. The two tasks of executive function were switching of attention and an electronic maze. Subjects were divided into four age groups, which were balanced for sex. We hypothesized that reduced cognitive performance among older healthy individuals would be associated with age-related changes in gamma phase synchrony. Results showed a significant decrease in executive function in the oldest (51-70 years) age group. ANOVAs of age-by-frontal Gamma synchrony also showed a significant effect of age on Gamma phase synchrony in the left frontal region that corresponded modestly to the age effect found on executive task performance, with reduced performance associated with increased gamma synchrony. The results indicate that age-related changes in cognitive function evident among elderly individuals may in part be related to decreased ability to integrate information and this may be reflected as a compensatory increase in gamma synchrony in frontal regions of the brain. PMID:16035141

  14. Structural changes in bunched crystalline ion beams

    International Nuclear Information System (INIS)

    Measurements of the spatial distribution of bunched crystalline ion beams in the radio frequency quadrupole storage ring PALLAS are presented for different ratios of the longitudinal and the transverse confinement strengths. The length of highly elongated crystalline ion bunches and its dependence on the bunching voltage is compared to predictions for a one-dimensional ion string and three-dimensional space-charge-dominated beams. The length is found to be considerably shorter than that predicted by the models. Furthermore, the scaling of the length with the bunching voltage is shown to differ from the expected inverse cube root scaling. These differences can partially be attributed to the formation of a mixed crystalline structure. Additionally, a concise mapping of the structural transition from a string to a zig-zag configuration as a function of the ratio of the confinement strengths is presented, which in a similar way deviates from the predictions

  15. Structural changes in bunched crystalline ion beams

    CERN Document Server

    Bussmann, M; Schätz, T; Habs, D

    2003-01-01

    Measurements of the spatial distribution of bunched crystalline ion beams in the radio frequency quadrupole storage ring PALLAS are presented for different ratios of the longitudinal and the transverse confinement strengths. The length of highly elongated crystalline ion bunches and its dependence on the bunching voltage is compared to predictions for a one-dimensional ion string and three-dimensional space-charge-dominated beams. The length is found to be considerably shorter than that predicted by the models. Furthermore, the scaling of the length with the bunching voltage is shown to differ from the expected inverse cube root scaling. These differences can partially be attributed to the formation of a mixed crystalline structure. Additionally, a concise mapping of the structural transition from a string to a zig-zag configuration as a function of the ratio of the confinement strengths is presented, which in a similar way deviates from the predictions.

  16. Population and Employment Densities: Structure and Change

    OpenAIRE

    Small, Kenneth A.; Song, Shunfeng

    1994-01-01

    We examine spatial patterns and their changes during the 1970s for the Los Angeles region, by estimating monocentric and polycentric density functions for employment and population. Downtown Los Angeles is clearly identified as the statistical monocentric center of the region, and it is the most consistently strong center in the polycentric patterns. Polycentric models fit statistically better than monocentric models, and there was some shift in employment distribution toward a more polycentr...

  17. Leading Change: Faculty Development through Structured Collaboration

    Directory of Open Access Journals (Sweden)

    Suzanne Painter

    2015-06-01

    Full Text Available There are relentless calls for innovation in higher education programs in response to media and policy-makers attention to such concerns as instructional quality, relevance to employment, costs, and time-to-degree. At the same time, the individual course remains the primary unit of instruction and there is little evidence of faculty development strategies to assist with changing core instructional practices. We faced that dilemma when we led an innovative doctoral program in educational leadership. Soon after beginning, we implemented a regular meeting of all faculty members teaching and advising in the program to address upcoming events and review student progress. Our retrospective analysis indicates that these meetings evolved as a practical and sustainable framework for faculty development in support of deep change for instructional practices. Here we describe the challenge of faculty development for change and draw lessons learned from our four years of leadership centered on experiential learning and community sense-making. We hope that program leaders who aspire to promote faculty development in conjunction with graduate program implementation will find these lessons useful.

  18. Age of Onset of Schizophrenia: Perspectives From Structural Neuroimaging Studies

    Science.gov (United States)

    Gogtay, Nitin; Vyas, Nora S.; Testa, Renee; Wood, Stephen J.; Pantelis, Christos

    2011-01-01

    Many of the major neuropsychiatric illnesses, including schizophrenia, have a typical age of onset in late adolescence. Late adolescence may reflect a critical period in brain development making it particularly vulnerable for the onset of psychopathology. Neuroimaging studies that focus on this age range may provide unique insights into the onset and course of psychosis. In this review, we examine the evidence from 2 unique longitudinal cohorts that span the ages from early childhood through young adulthood; a study of childhood-onset schizophrenia where patients and siblings are followed from ages 6 through to their early twenties, and an ultra-high risk study where subjects (mean age of 19 years) are studied before and after the onset of psychosis. From the available evidence, we make an argument that subtle, regionally specific, and genetically influenced alterations during developmental age windows influence the course of psychosis and the resultant brain phenotype. The importance of examining trajectories of development and the need for future combined approaches, using multimodal imaging together with molecular studies is discussed. PMID:21505117

  19. Age of onset of schizophrenia: perspectives from structural neuroimaging studies.

    Science.gov (United States)

    Gogtay, Nitin; Vyas, Nora S; Testa, Renee; Wood, Stephen J; Pantelis, Christos

    2011-05-01

    Many of the major neuropsychiatric illnesses, including schizophrenia, have a typical age of onset in late adolescence. Late adolescence may reflect a critical period in brain development making it particularly vulnerable for the onset of psychopathology. Neuroimaging studies that focus on this age range may provide unique insights into the onset and course of psychosis. In this review, we examine the evidence from 2 unique longitudinal cohorts that span the ages from early childhood through young adulthood; a study of childhood-onset schizophrenia where patients and siblings are followed from ages 6 through to their early twenties, and an ultra-high risk study where subjects (mean age of 19 years) are studied before and after the onset of psychosis. From the available evidence, we make an argument that subtle, regionally specific, and genetically influenced alterations during developmental age windows influence the course of psychosis and the resultant brain phenotype. The importance of examining trajectories of development and the need for future combined approaches, using multimodal imaging together with molecular studies is discussed. PMID:21505117

  20. Nuclear power plant life extension: How aging affects performance of containments & other structures

    Institute of Scientific and Technical Information of China (English)

    Robert A Dameron; Sun Junling

    2013-01-01

    This paper focuses on how aging can affect performance of safety-related structures in nuclear power plant (NPP).Knowledge and assessment of impacts of aging on structures are essential to plant life extension analysis,especially performance to severe loadings such as loss-of-coolant-accidents or major seismic events.Plant life extension issues are of keen interest in countries (like the United States) which have a large,aging fleet of NPPs.This paper addresses the overlap and relationship of structure aging to severe loading performance,with particular emphasis on containment structures.

  1. Structural conformation and leaching from in vitro aged and retrieved Invisalign appliances.

    Science.gov (United States)

    Schuster, Susan; Eliades, George; Zinelis, Spiros; Eliades, Theodore; Bradley, T Gerard

    2004-12-01

    The objectives of this study were to investigate the structure of Invisalign appliances (Align Technology, Santa Clara, Calif) after intraoral exposure, and to qualitatively and quantitatively characterize the substances leached from the aligners after accelerated in vitro aging. Samples of Invisalign appliances were randomly selected from 10 patients before intraoral placement and after retrieval, and the prepared specimens were subjected to (1) bright-field optical reflection microscopy to study the surface morphology; (2) Fourier transform infrared microspectroscopy to characterize the in vivo changes in molecular composition induced on appliance surfaces, (3) scanning electron microscopy and energy dispersive X-ray microanalysis to identify the elemental composition of integuments formed on the surface, and (4) Vickers hardness (HV 200) testing. Another set of reference and retrieved appliances was subjected to artificial aging for 2 weeks, and the extracts were subjected to gas chromatography-mass spectroscopy. The retrieved appliances demonstrated substantial morphological variation relative to the as-received specimens involving abrasion at the cusp tips, adsorption of integuments, and localized calcification of the precipitated biofilm at stagnation sites. Buccal segments of retrieved appliances showed an increase in hardness, which might be attributed to mastication-induced cold work; however, the clinical implication of this effect on mechanotherapy is unknown. In vitro aged and retrieved appliances were found to leach no traceable amount of substances in an ethanol aging solution.

  2. Age-related changes in predictive capacity versus internal model adaptability: electrophysiological evidence that individual differences outweigh effects of age

    Directory of Open Access Journals (Sweden)

    Ina eBornkessel-Schlesewsky

    2015-11-01

    Full Text Available Hierarchical predictive coding has been identified as a possible unifying principle of brain function, and recent work in cognitive neuroscience has examined how it may be affected by age–related changes. Using language comprehension as a test case, the present study aimed to dissociate age-related changes in prediction generation versus internal model adaptation following a prediction error. Event-related brain potentials (ERPs were measured in a group of older adults (60–81 years; n=40 as they read sentences of the form The opposite of black is white/yellow/nice. Replicating previous work in young adults, results showed a target-related P300 for the expected antonym (white; an effect assumed to reflect a prediction match, and a graded N400 effect for the two incongruous conditions (i.e. a larger N400 amplitude for the incongruous continuation not related to the expected antonym, nice, versus the incongruous associated condition, yellow. These effects were followed by a late positivity, again with a larger amplitude in the incongruous non-associated versus incongruous associated condition. Analyses using linear mixed-effects models showed that the target-related P300 effect and the N400 effect for the incongruous non-associated condition were both modulated by age, thus suggesting that age-related changes affect both prediction generation and model adaptation. However, effects of age were outweighed by the interindividual variability of ERP responses, as reflected in the high proportion of variance captured by the inclusion of by-condition random slopes for participants and items. We thus argue that – at both a neurophysiological and a functional level – the notion of general differences between language processing in young and older adults may only be of limited use, and that future research should seek to better understand the causes of interindividual variability in the ERP responses of older adults and its relation to cognitive

  3. Probing structural changes of self assembled i-motif DNA

    KAUST Repository

    Lee, Iljoon

    2015-01-01

    We report an i-motif structural probing system based on Thioflavin T (ThT) as a fluorescent sensor. This probe can discriminate the structural changes of RET and Rb i-motif sequences according to pH change. This journal is

  4. Variation Principles and Applications in the Study of Cell Structure and Aging

    Science.gov (United States)

    Economos, Angelos C.; Miquel, Jaime; Ballard, Ralph C.; Johnson, John E., Jr.

    1981-01-01

    In this report we have attempted to show that "some reality lies concealed in biological variation". This "reality" has its principles, laws, mechanisms, and rules, only a few of which we have sketched. A related idea we pursued was that important information may be lost in the process of ignoring frequency distributions of physiological variables (as is customary in experimental physiology and gerontology). We suggested that it may be advantageous to expand one's "statistical field of vision" beyond simple averages +/- standard deviations. Indeed, frequency distribution analysis may make visible some hidden information not evident from a simple qualitative analysis, particularly when the effect of some external factor or condition (e.g., aging, dietary chemicals) is being investigated. This was clearly illustrated by the application of distribution analysis in the study of variation in mouse liver cellular and fine structure, and may be true of fine structural studies in general. In living systems, structure and function interact in a dynamic way; they are "inseparable," unlike in technological systems or machines. Changes in fine structure therefore reflect changes in function. If such changes do not exceed a certain physiologic range, a quantitative analysis of structure will provide valuable information on quantitative changes in function that may not be possible or easy to measure directly. Because there is a large inherent variation in fine structure of cells in a given organ of an individual and among individuals, changes in fine structure can be analyzed only by studying frequency distribution curves of various structural characteristics (dimensions). Simple averages +/- S.D. do not in general reveal all information on the effect of a certain factor, because often this effect is not uniform; on the contrary, this will be apparent from distribution analysis because the form of the curves will be affected. We have also attempted to show in this chapter that

  5. Local structure changes of Cu55 cluster during heating

    Institute of Scientific and Technical Information of China (English)

    Zhang Lin; Zhang Cai-Bei; Qi Yang

    2007-01-01

    The structural relaxation of a cluster containing 55 atoms at elevated temperatures is simulated by molecular dynamics. The interatomic interactions are given by using the embedded atom method (EAM) potential. By decomposing the peaks of the radial distribution functions (RDFs) according to the pair analysis technique, the local structural patterns are identified for this cluster. During increasing temperature, structural changes of different shells determined by atom density profiles result in an abrupt increase in internal energy. The simulations show how local structural changes can strongly cause internal energy to change accordingly.

  6. A Drosophila model for age-associated changes in sleep:wake cycles

    OpenAIRE

    Koh, Kyunghee; Evans, Joshua M.; Hendricks, Joan C.; Sehgal, Amita

    2006-01-01

    One of the most consistent behavioral changes that occurs with age in humans is the loss of sleep consolidation. This can be quite disruptive and yet little is known about its underlying basis. To better understand the effects of aging on sleep:wake cycles, we sought to study this problem in Drosophila melanogaster, a powerful system for research on aging and behavior. By assaying flies of different ages as well as monitoring individual flies constantly over the course of their lifetime, we f...

  7. Personality in old and very old age: stability but also change

    OpenAIRE

    Mõttus, Rene; Johnson, Wendy; Deary, Ian

    2011-01-01

    Personality development in old age is a largely underexplored area, especially in the ninth decade of life. Lothian Birth Cohorts 1936 and 1921 were used to study the longitudinal stability and change of Five-Factor Model personality traits from ages 69 to 72 years and from ages 81 to 87 years, and cross-cohort stability and mean-level differences between ages 69 and 81 years. Measurements within the FFM framework appeared to be adequately stable both within and across cohorts, and high rank-...

  8. Changes in the morphology of porous anodic films formed on aluminium in natural and artificial ageing

    Directory of Open Access Journals (Sweden)

    López, V.

    2003-12-01

    Full Text Available Transmission electron microscopy and electrochemical impedance spectroscopy are used to demonstrate that the water retained in porous anodic aluminium oxide films is the main reason for their reactivity under electron beam irradiation in the TEM, accelerated ageing in an oven at 100 °C, or natural ageing over months and years in an outdoor atmosphere. Though the kinetics in each medium is highly different, there is a clear similarity between the structural and physical-chemical transformations that take place. Unsealed layers, practically free of water, hardly change their structure under the effect of electron beams and show the same impedance plots after hours at 100 °C or after years at environmental temperature in dry atmospheres.

    La microscopía electrónica de transmisión, por una parte, y la espectroscopia de impedancia electroquímica, por otra, demuestran que el agua retenida en las películas anódicas porosas de óxido de aluminio es la principal responsable de su reactividad bajo la irradiación del haz de electrones en el MET, en el envejecimiento acelerado en la estufa a 100 ºC o en el envejecimiento natural de meses y años en la atmósfera a temperatura ambiente. Aunque, de cinéticas muy diferentes, existe una indudable semejanza entre las transformaciones estructurales y físico-químicas que tienen lugar en los tres medios. Las capas sin sellar, prácticamente exentas de agua, apenas cambian su estructura por efecto del haz de electrones y muestran los mismos diagramas de impedancia después de horas a 100 ºC o de años a temperatura ambiente en atmósferas secas.

  9. Upgrade and Design of Coastal Structures Exposed to Climate Changes

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Quvang Harck

    This thesis “Upgrade and Design of Coastal Structures Exposed to Climate Changes” evaluates the performance of existing types of structures when exposed to climate changes. This includes also the potential of using cost‐sharing multipurpose structures for protection against the effects of future...... climate changes. The thesis consists of three parts. The first part evaluates the performance of existing design formulae for estimation of wave actions on structures, especially in shallow water since these structures are most vulnerable to the rising sea water levels caused by climate changes. Existing...... of coastal protection structures, which are extended to a wider range of wave conditions, and which can be used to more accurately estimate the influence from climate changes. In the second part of the thesis, the extended and modified formulae are used in case studies to evaluate the influence from climate...

  10. Glutamate-related gene expression changes with age in the mouse auditory midbrain.

    Science.gov (United States)

    Tadros, Sherif F; D'Souza, Mary; Zettel, Martha L; Zhu, Xiaoxia; Waxmonsky, Nicole C; Frisina, Robert D

    2007-01-01

    Glutamate is the main excitatory neurotransmitter in both the peripheral and central auditory systems. Changes of glutamate and glutamate-related genes with age may be an important factor in the pathogenesis of age-related hearing loss-presbycusis. In this study, changes in glutamate-related mRNA gene expression in the CBA mouse inferior colliculus with age and hearing loss were examined and correlations were sought between these changes and functional hearing measures, such as the auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAEs). Gene expression of 68 glutamate-related genes was investigated using both genechip microarray and real-time PCR (qPCR) molecular techniques for four different age/hearing loss CBA mouse subject groups. Two genes showed consistent differences between groups for both the genechip and qPCR. Pyrroline-5-carboxylate synthetase enzyme (Pycs) showed down-regulation with age and a high-affinity glutamate transporter (Slc1a3) showed up-regulation with age and hearing loss. Since Pycs plays a role in converting glutamate to proline, its deficiency in old age may lead to both glutamate increases and proline deficiencies in the auditory midbrain, playing a role in the subsequent inducement of glutamate toxicity and loss of proline neuroprotective effects. The up-regulation of Slc1a3 gene expression may reflect a cellular compensatory mechanism to protect against age-related glutamate or calcium excitoxicity.

  11. The age structure of the Milky Way's halo

    CERN Document Server

    Carollo, Daniela; Placco, Vinicius; Santucci, Rafael; Denissenkov, Pavel; Tissera, Patricia; Lentner, Geoffrey; Rossi, Silvia; Lee, Young Sun; Tumlinson, Jason

    2016-01-01

    We present a new, high-resolution chronographic (age) map of the Milky Way's halo, based on the inferred ages of ~130,000 field blue horizontal-branch (BHB) stars with photometry from the Sloan Digital Sky Survey. Our map exhibits a strong central concentration of BHB stars with ages greater than 12 Gyr, extending up to ~15 kpc from the Galactic center (reaching close to the solar vicinity), and a decrease in the mean ages of field stars with distance by 1-1.5 Gyr out to ~45-50 kpc, along with an apparent increase of the dispersion of stellar ages, and numerous known (and previously unknown) resolved over-densities and debris streams, including the Sagittarius Stream. These results agree with expectations from modern LambdaCDM cosmological simulations, and support the existence of a dual (inner/outer) halo system, punctuated by the presence of over-densities and debris streams that have not yet completely phase-space mixed.

  12. Lake Erie Yellow perch age estimation based on three structures: Precision, processing times, and management implications

    Science.gov (United States)

    Vandergoot, C.S.; Bur, M.T.; Powell, K.A.

    2008-01-01

    Yellow perch Perca flavescens support economically important recreational and commercial fisheries in Lake Erie and are intensively managed. Age estimation represents an integral component in the management of Lake Erie yellow perch stocks, as age-structured population models are used to set safe harvest levels on an annual basis. We compared the precision associated with yellow perch (N = 251) age estimates from scales, sagittal otoliths, and anal spine sections and evaluated the time required to process and estimate age from each structure. Three readers of varying experience estimated ages. The precision (mean coefficient of variation) of estimates among readers was 1% for sagittal otoliths, 5-6% for anal spines, and 11-13% for scales. Agreement rates among readers were 94-95% for otoliths, 71-76% for anal spines, and 45-50% for scales. Systematic age estimation differences were evident among scale and anal spine readers; less-experienced readers tended to underestimate ages of yellow perch older than age 4 relative to estimates made by an experienced reader. Mean scale age tended to underestimate ages of age-6 and older fish relative to otolith ages estimated by an experienced reader. Total annual mortality estimates based on scale ages were 20% higher than those based on otolith ages; mortality estimates based on anal spine ages were 4% higher than those based on otolith ages. Otoliths required more removal and preparation time than scales and anal spines, but age estimation time was substantially lower for otoliths than for the other two structures. We suggest the use of otoliths or anal spines for age estimation in yellow perch (regardless of length) from Lake Erie and other systems where precise age estimates are necessary, because age estimation errors resulting from the use of scales could generate incorrect management decisions. ?? Copyright by the American Fisheries Society 2008.

  13. THE GENETIC STRUCTURE OF DIFFERENT AGE GROUPS OF SILVER (HYPOPHTHALMICHTHYS MOLITRIX AND BIGHEAD (ARISTICHTHYS NOBILIS CARPS FROM FISH FARM LIMANSKE

    Directory of Open Access Journals (Sweden)

    Т. Nagorniuk

    2015-09-01

    bighead carps to control the level of interspecies genetic variability. The obtained experimental data of the genetic structure analysis of silver and bighead carps of different age groups will be used for the monitoring of the genetic structure changes during their adaptation to new environmental conditions.

  14. Forecast of the Chemical Aging and Relevant Color Changes in Painting

    CERN Document Server

    Zilbergleyt, B

    2005-01-01

    The article describes the potential application of thermodynamic simulation to forecast chemical aging and relevant color changes in painting. Qualitative and numerical results were obtained by applying the method to various mixtures of pigments without and with atmospheric components. The results were compared to the legendary recommendations on incompatible pigment mixtures with about an 80 percent match regarding potential color changes in the aged mixtures. Results for the cadmium yellow-lead white and cadmium lemon-emerald green mixtures are illustrated by pictures, gradually showing color changes caused by the aging. The method of thermodynamic simulation can be a powerful tool to investigate old masterpieces, in developing new materials, and to forecast some aspects of the aging of real masterpieces.

  15. Changing the mindset[Lightweight composite structures

    Energy Technology Data Exchange (ETDEWEB)

    DeLuca, M.

    2002-12-01

    Advances in the use of composite technology are some of the more closely watched in the industry. In the industry all agree that to go deeper systems must get lighter, one way being examined is the replacement of heavy steel systems with lightweight composite structures.Composites offer high strength-to-weight ratio, fatigue, and corrosion-resistance, design flexibility, thermal insulation and stiffness over steel systems. Although generally more expensive on a direct component to component comparison, results in overall lower system cost, especially in the deepwater. Conoco-Phillips are one of the industry's leading advocates of composite technology advancement and this article reports on the discussions the author had with a senior research fellow of the company. Details of the research that has been carried out and how far these developments have reached are covered here.

  16. Structure Change of the Insulating Composite

    Directory of Open Access Journals (Sweden)

    Vaclav Mentlik

    2008-01-01

    Full Text Available Modern power electric drives brought advantages in induction motor control. In the same time appeared problems with high frequency square waveform voltage (pulse stress produced by the voltage converters. Voltage converters produce repetitive pulses with high level of voltage rise fronts (slew rates. Rise fronts attained values of up to tens kilovolts per microsecond and voltage pulse repetition frequency up to some tens of kilohertz. This technology is an advantage for a drive control. Significant is the impact of these voltage waveforms on the motor insulations. Degradation of the main wall insulation can reduce the reliability of the electric motor and whole drive. In this paper is discussed one possible solution. The promising modification in the insulation material structure is presented in the paper.

  17. A Structural Equation Model of Conceptual Change in Physics

    Science.gov (United States)

    Taasoobshirazi, Gita; Sinatra, Gale M.

    2011-01-01

    A model of conceptual change in physics was tested on introductory-level, college physics students. Structural equation modeling was used to test hypothesized relationships among variables linked to conceptual change in physics including an approach goal orientation, need for cognition, motivation, and course grade. Conceptual change in physics…

  18. The Analysis of the Age Structure of Regional Fixed Capital in the Agriculture

    Directory of Open Access Journals (Sweden)

    P. Mazouch

    2016-06-01

    Full Text Available The paper deals with an estimate and analysis of the value of regional net fixed capital stock and the age structure of machinery and equipment in Czech agriculture. In order to perform such analysis, the official model of perpetual inventory method is transformed into the Markov chain model and applied on regional data separately. Regional net fixed capital stock is presented for the period of 2008-2013. The development of the average age of machinery and equipment comprises a potential indicator of the modernisation process in the industry. The analysis of the age structure is based on the structure heterogeneity indicator. For these purposes, the real age structure in each Czech region is compared with the theoretical stable and stationary structure. Currently, the most heterogeneous age structure of machinery and equipment occurs in Prague and the Karlovy Vary region.

  19. Changes in waist circumference and mortality in middle-aged men and women

    DEFF Research Database (Denmark)

    Berentzen, Tina Landsvig; Jakobsen, Marianne Uhre; Halkjaer, Jytte;

    2010-01-01

    Waist circumference (WC) adjusted for body mass index (BMI) is positively associated with mortality, but the association with changes in WC is less clear. We investigated the association between changes in WC and mortality in middle-aged men and women, and evaluated the influence from concurrent...

  20. Changes in waist circumference and the incidence of diabetes in middle-aged men and women

    DEFF Research Database (Denmark)

    Berentzen, Tina Landsvig; Jakobsen, Marianne Uhre; Halkjaer, Jytte;

    2011-01-01

    Waist circumference (WC) is positively associated with diabetes, but the association with changes in WC (DWC) is less clear. We investigated the association between DWC and the subsequent risk of diabetes in middle-aged men and women, and evaluated the influence from concurrent changes in body mass...

  1. Age-related changes in the transmission properties of the human lens and their relevance to circadian entrainment

    DEFF Research Database (Denmark)

    Kessel, Line; Lundeman, Jesper Holm; Herbst, Kristina;

    2010-01-01

    To characterize age-related changes in the transmission of light through noncataractous human lenses.......To characterize age-related changes in the transmission of light through noncataractous human lenses....

  2. The impact of ageing and changing utilization patterns on future cardiovascular drug expenditure: a pharmacoepidemiological projection approach

    DEFF Research Database (Denmark)

    Kildemoes, Helle Wallach; Andersen, Morten; Støvring, Henrik

    2010-01-01

    To develop a method for projecting the impact of ageing and changing drug utilization patterns on future drug expenditure.......To develop a method for projecting the impact of ageing and changing drug utilization patterns on future drug expenditure....

  3. Age-structured optimal control in population economics

    OpenAIRE

    Gustav Feichtinger; Alexia Prskawetz; Veliov, Vladimir M.

    2002-01-01

    This paper brings both intertemporal and age-dependent features to a theory of population policy at the macro-level. A Lotkatype renewal model of population dynamics is combined with a Solow/Ramsey economy. By using a new maximum principle for distributed parameter control we derive meaningful qualitative results for the optimal migration path and the optimal saving rate.

  4. Topography and the structure of the surface of polyamide - glass composites after the ageing process

    Directory of Open Access Journals (Sweden)

    A. Pusz

    2011-01-01

    Full Text Available Purpose: Polymers have found applications in such diverse biomedical fields as tissue engineering, implantation of medical devices and artificial organs, prostheses, ophthalmology, dentistry, bone repair and many other medical fields. The requirements for materials used in the construction of removable dentures are becoming more and more demanding. The introduction of improved flexible materials has been a considerable advance. The aim of this work was to determine how the structure of thermoplastic materials changes over time in terms of weight changes and artificial saliva sorption. Purpose of this paper was to evaluate the influence of the ageing process on structure of polyamide - glass composites applied in dentistry.Design/methodology/approach: Polyamide samples about the diversified content of the glass fibre were produced with method of the injection moulding. Denotation the absorbency of artificial saliva was performed on standardized samples according to the norm. Samples were dried off to fixed mass, and then they were soaked in artificial saliva. Three temperatures of examination were applied 20ºC, 35ºC and 50ºC.Findings: Examinations allowed to show that the absorbency of artificial saliva through composite is dependent on the temperature.Research limitations/implications: To fully evaluate the influence of the ageing process on mechanical properties of polyamide - glass composites applied in human body environment it is planned to continue described research. Simultaneous influence of the ageing process on mechanical properties of polyamide - glass composites will be tested.Originality/value: Applying strengthened thermoplastics with glass fibre on dentures is a new look at materials applied in dentistry.

  5. Protein profile changes during porcine oocyte aging and effects of caffeine on protein expression patterns.

    Directory of Open Access Journals (Sweden)

    Guang-Jian Jiang

    Full Text Available It has been shown that oocyte aging critically affects reproduction and development. By using proteomic tools, in the present study, changes in protein profiles during porcine oocyte aging and effects of caffeine on oocyte aging were investigated. By comparing control MII oocytes with aging MII oocytes, we identified 23 proteins that were up-regulated and 3 proteins that were down-regulated during the aging process. In caffeine-treated oocytes, 6 proteins were identified as up-regulated and 12 proteins were identified as down-regulated. A total of 38 differentially expressed proteins grouped into 5 regulation patterns were determined to relate to the aging and anti-aging process. By using the Gene Ontology system, we found that numerous functional gene products involved in metabolism, stress response, reactive oxygen species and cell cycle regulation were differentially expressed during the oocyte aging process, and most of these proteins are for the first time reported in our study, including 2 novel proteins. In addition, several proteins were found to be modified during oocyte aging. These data contribute new information that may be useful for future research on cellular aging and for improvement of oocyte quality.

  6. Study on Land Use Structure Changes and Countermeasures

    Institute of Scientific and Technical Information of China (English)

    Zhiyou; LIU; Chunling; PU; Airong; ZHU; Zhiqiang; WANG

    2013-01-01

    Land structure change not only relates to the coordinated development of regional social economic,but also determines the ecological environment security in certain region. Ili river valley was chose as the study area. The scientific and quantitative assessment of land use struc- ture and spatial pattern is significant to the sustainable development of the Ili river valley area. Based on the detailed investigation date of land use from 2002 to 2008,and social and economic statistics of the Ili river valley in eight counties and one city in 2008,the study area’s land use structure changes were discussed in three aspects from the land use structure,the degree of land use,to the land use efficiency. The changes of land use structure were analyzed by the use of qualitative and quantitative methods. Factors that influence land use structure changes were analyzed. In the end,suggestions were put forward to optimize the management.

  7. Mathematical modeling of left ventricular dimensional changes in mice during aging

    Directory of Open Access Journals (Sweden)

    Yang Tianyi

    2012-12-01

    Full Text Available Abstract Cardiac aging is characterized by diastolic dysfunction of the left ventricle (LV, which is due in part to increased LV wall stiffness. In the diastolic phase, myocytes are relaxed and extracellular matrix (ECM is a critical determinant to the changes of LV wall stiffness. To evaluate the effects of ECM composition on cardiac aging, we developed a mathematical model to predict LV dimension and wall stiffness changes in aging mice by integrating mechanical laws and our experimental results. We measured LV dimension, wall thickness, LV mass, and collagen content for wild type (WT C57/BL6J mice of ages ranging from 7.3 months to those of 34.0 months. The model was established using the thick wall theory and stretch-induced tissue growth to an isotropic and homogeneous elastic composite with mixed constituents. The initial conditions of the simulation were set based on the data from the young mice. Matlab simulations of this mathematical model demonstrated that the model captured the major features of LV remodeling with age and closely approximated experimental results. Specifically, the temporal progression of the LV interior and exterior dimensions demonstrated the same trend and order-of-magnitude change as our experimental results. In conclusion, we present here a validated mathematical model of cardiac aging that applies the thick-wall theory and stretch-induced tissue growth to LV remodeling with age.

  8. Gene Transcriptional and Metabolic Profile Changes in Mimetic Aging Mice Induced by D-Galactose.

    Directory of Open Access Journals (Sweden)

    Yue-Yue Zhou

    Full Text Available D-galactose injection has been shown to induce many changes in mice that represent accelerated aging. This mouse model has been widely used for pharmacological studies of anti-aging agents. The underlying mechanism of D-galactose induced aging remains unclear, however, it appears to relate to glucose and 1ipid metabolic disorders. Currently, there has yet to be a study that focuses on investigating gene expression changes in D-galactose aging mice. In this study, integrated analysis of gas chromatography/mass spectrometry-based metabonomics and gene expression profiles was used to investigate the changes in transcriptional and metabolic profiles in mimetic aging mice injected with D-galactose. Our findings demonstrated that 48 mRNAs were differentially expressed between control and D-galactose mice, and 51 potential biomarkers were identified at the metabolic level. The effects of D-galactose on aging could be attributed to glucose and 1ipid metabolic disorders, oxidative damage, accumulation of advanced glycation end products (AGEs, reduction in abnormal substance elimination, cell apoptosis, and insulin resistance.

  9. Computed tomographic features of the feline brain change with advancing age?

    Directory of Open Access Journals (Sweden)

    Viviam R. Babicsak

    2015-12-01

    Full Text Available Abstract: A better understanding of normal or expected encephalic changes with increasing age in cats is needed as a growing number of these animals is attended in veterinary clinics, and imaging data referring to normal age-associated changes are extremely scarce in the literature. The objective of this study was to identify age-related changes in feline brain using CT imaging. Fifteen non-brachycephalic healthy cats with age between 1 to 6 years (adult group and others over 12 years (geriatric group were submitted to CT scan of the brain. Statistically significant differences were found between the groups for the ability to identify the left lateral ventricle and for falx cerebri calcification, both identified in a greater number of cats of the geriatric group. A significantly higher mean width of the third ventricle was also detected in geriatric animals. There were no statistically significant differences between lateral ventricular dimensions and encephalic parenchymal attenuation on pre and post-contrast CT phases. The results of the present study show an increase in the incidence of falx cerebri calcification and a third ventricular dilatation with advancing age in cats. Future researches using MRI scanners and a greater quantity of cats are needed in order to identify supplementary age-related changes.

  10. The effects of healthy aging on cerebral hemodynamic responses to posture change

    International Nuclear Information System (INIS)

    Aging is associated with an increased incidence of orthostatic hypotension, impairment of the baroreceptor reflex and lower baseline cerebral blood flow. The effect of aging on cerebrovascular autoregulation, however, remains to be fully elucidated. We used a novel optical instrument to assess microvascular cerebral hemodynamics in the frontal lobe cortex of 60 healthy subjects ranging from ages 20–78. Diffuse correlation spectroscopy (DCS) and near-infrared spectroscopy (NIRS) were used to measure relative cerebral blood flow (rCBF), total hemoglobin concentration (THC), oxyhemoglobin concentration (HbO2) and deoxyhemoglobin concentration (Hb). Cerebral hemodynamics were monitored for 5 min at each of the following postures: head-of-bed 30°, supine, standing and supine. Supine-to-standing posture change caused significant declines in rCBF, THC and HbO2, and an increase in Hb, across the age continuum (p < 0.01). Healthy aging did not alter postural changes in frontal cortical rCBF (p = 0.23) and was associated with a smaller magnitude of decline in HbO2 (p < 0.05) during supine-to-standing posture change. We conclude that healthy aging does not alter postural changes in frontal cortical perfusion

  11. Cellular changes in the hamster testicular interstitium with ageing and after exposure to short photoperiod.

    Science.gov (United States)

    Beltrán-Frutos, E; Seco-Rovira, V; Ferrer, C; Madrid, J F; Sáez, F J; Canteras, M; Pastor, L M

    2016-04-01

    The aim of this study was to evaluate the cellular changes that occur in the hamster testicular interstitium in two very different physiological situations involving testicular involution: ageing and exposure to a short photoperiod. The animals were divided into an 'age group' with three subgroups - young, adult and old animals - and a 'regressed group' with animals subjected to a short photoperiod. The testicular interstitium was characterised by light and electron microscopy. Interstitial cells were studied histochemically with regard to their proliferation, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP in situ nick end labelling (TUNEL+) and testosterone synthetic activity. We identified two types of Leydig cell: Type A cells showed a normal morphology, while Type B cells appeared necrotic. With ageing, pericyte proliferation decreased but there was no variation in the index of TUNEL-positive Leydig cells. In the regressed group, pericyte proliferation was greater and TUNEL-positive cells were not observed in the interstitium. The testicular interstitium suffered few ultrastructural changes during ageing and necrotic Leydig cells were observed. In contrast, an ultrastructural involution of Leydig cells with no necrosis was observed in the regressed group. In conclusion, the testicular interstitium of Mesocricetus auratus showed different cellular changes in the two groups (age and regressed), probably due to the irreversible nature of ageing and the reversible character of changes induced by short photoperiod. PMID:25437143

  12. Longitudinal Volumetric Brain Changes in Autism Spectrum Disorder Ages 6–35 Years

    Science.gov (United States)

    Lange, Nicholas; Travers, Brittany G.; Bigler, Erin D.; Prigge, Molly B.D.; Froehlich, Alyson L.; Nielsen, Jared A.; Cariello, Annahir N.; Zielinski, Brandon A.; Anderson, Jeffrey S.; Fletcher, P. Thomas; Alexander, Andrew A.; Lainhart, Janet E.

    2014-01-01

    LAY ABSTRACT Since the impairments associated with autism spectrum disorder (ASD) tend to persist or worsen from childhood into adulthood, it is of critical importance to examine how the brain develops over this growth epoch. We report initial findings on whole and regional longitudinal brain development in 100 male participants with ASD (226 high-quality MRI scans) compared to 56 typically developing male controls (TDCs) (117 high-quality scans) from childhood into adulthood, for a total of 156 participants scanned over an eight-year period. We provide volumetric growth curves for the entire brain, total gray matter (GM), frontal GM, temporal GM, parietal GM, occipital GM, total cortical white matter (WM), corpus callosum, caudate, thalamus, total cerebellum, and total ventricles. Mean volume of cortical WM was reduced significantly. Decreases in regional mean volumes in the ASD sample were most often due to decreases during late adolescence and adulthood. The growth curve of whole-brain volume showed increased volumes in young children with autism and subsequently decreased during adolescence to meet the TDC curve between 10 and 15 years of age. The volume of many structures continued to decline atypically into adulthood in the ASD sample. The data suggest that ASD is a dynamic disorder with complex changes in whole and regional brain volumes that change over time from childhood into adulthood. SCIENTIFIC ABSTRACT Since the impairments associated with autism spectrum disorder (ASD) tend to persist or worsen from childhood into adulthood, it is of critical importance to examine how the brain develops over this growth epoch. We report initial findings on whole and regional longitudinal brain development in 100 male participants with ASD (226 high-quality MRI scans; mean inter-scan interval 2.7 years) compared to 56 typically developing male controls (TDCs) (117 high-quality scans; mean inter-scan interval 2.6 years) from childhood into adulthood, for a total of 156

  13. Generation time, net reproductive rate, and growth in stage-age-structured populations

    DEFF Research Database (Denmark)

    Steiner, Uli; Tuljapurkar, Shripad; Coulson, Tim

    2014-01-01

    to age-structured populations. Here we generalize this result to populations structured by stage and age by providing a new, unique measure of reproductive timing (Tc) that, along with net reproductive rate (R0), has a direct mathematical relationship to and approximates growth rate (r). We use simple...

  14. 15 CFR 50.5 - Fee structure for age search and citizenship information.

    Science.gov (United States)

    2010-01-01

    ... THE CENSUS § 50.5 Fee structure for age search and citizenship information. Type of service Fee... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Fee structure for age search and citizenship information. 50.5 Section 50.5 Commerce and Foreign Trade Regulations Relating to Commerce...

  15. Reference ranges and age-related changes of peripheral blood lymphocyte subsets in Chinese healthy adults

    Institute of Scientific and Technical Information of China (English)

    JIAO Yang; QIU ZhiFeng; XIE Jing; LI DongJing; LI TaiSheng

    2009-01-01

    This study was performed to build region-specific reference ranges of peripheral blood lymphocyte subsets for Chinese healthy adults from the young to the elderly and analyze the trends of changes in lymphocyte subsets for evaluating the impact of age on the values. 151 healthy adults aged 19-86 were recruited based on the SENIEUR protocol. Three sets of reference ranges were finally built applicable for the healthy young (19-44 years), middle-aged (45-64 years) and elder adults (>65). Comparisons in parameters among the three cohorts showed that e statistically significant increase in CD16CD56+ NK cell was observed between the middle-aged and elder cohorts, whereas for the majority of the parameters, a significant decline was observed between the young and the middle-aged cohorts.Further results showed that inverse correlations were observed between the age and CD19+ B, CD3+T,CD3+CD4+1, CD4+CD45RA+CD62L+ naTve T cell and CD4+CD28+/CD4+, while the positive one was identified between the age end the NK cell. These significant changes of the most of immune parameters provided evidence for immunosenescence. Notably, T cell activation markers of CD8+CD38+ and CD8+HLA-DR+ showed reverse trends of association with age, which provides a clue for further researches on the mechanisms underlying the paradoxical clinical presentation of the elder patients.

  16. Aging changes in the kidneys of two poeciliid fishes, the guppy Poecilia reticulatus and the Amazon molly P. formosa

    Energy Technology Data Exchange (ETDEWEB)

    Woodhead, A.D.; Pond, V.; Dailey, K.

    1983-01-01

    Histological surveys of the kidneys of two poeciliid fishes, the Amazon molly Poecilia formosa and the guppy P. reticulatus, throughout their lifespans showed no regular aging trends. Few kidney lesions were found in the Amazon molly until very late in life, 60 months or more, when obsolescent glomeruli and dilated renal tubules occurred. Guppies showed involutional changes of the renal system earlier, and the lesions became more severe with age, particularly in male fish. Hemopoietic tissue was reduced in amount in older fish of both species. Guppies of a year and older had marked accumulation of melanin in the melanomacrophage centers of the kidney, and the amount present increased with age. By contrast, there was little melanin deposition in mollies until almost the end of the lifespan. Hyaline droplets were consistently seen in the renal tubules of the mollies, but were rare in guppies. The degenerative changes in the kidneys of these two teleosts are similar to those seen in the kidneys of aging mammals. Despite the loss of normal structure in older fish, it seemed unlikely that degeneration of the kidney was directly involved in aging and death.

  17. Early-age hydration and volume change of calcium sulfoaluminate cement-based binders

    Science.gov (United States)

    Chaunsali, Piyush

    Shrinkage cracking is a predominant deterioration mechanism in structures with high surface-to-volume ratio. One way to allay shrinkage-induced stresses is to use calcium sulfoaluminate (CSA) cement whose early-age expansion in restrained condition induces compressive stress that can be utilized to counter the tensile stresses due to shrinkage. In addition to enhancing the resistance against shrinkage cracking, CSA cement also has lower carbon footprint than that of Portland cement. This dissertation aims at improving the understanding of early-age volume change of CSA cement-based binders. For the first time, interaction between mineral admixtures (Class F fly ash, Class C fly ash, and silica fume) and OPC-CSA binder was studied. Various physico-chemical factors such as the hydration of ye'elimite (main component in CSA cement), amount of ettringite (the main phase responsible for expansion in CSA cement), supersaturation with respect to ettringite in cement pore solution, total pore volume, and material stiffness were monitored to examine early-age expansion characteristics. This research validated the crystallization stress theory by showing the presence of higher supersaturation level of ettringite, and therefore, higher crystallization stress in CSA cement-based binders. Supersaturation with respect to ettringite was found to increase with CSA dosage and external supply of gypsum. Mineral admixtures (MA) altered the expansion characteristics in OPC-CSA-MA binders with fixed CSA cement. This study reports that fly ash (FA) behaves differently depending on its phase composition. The Class C FA-based binder (OPC-CSA-CFA) ceased expanding beyond two days unlike other OPC-CSA-MA binders. Three factors were found to govern expansion of CSA cement-based binders: 1) volume fraction of ettringite in given pore volume, 2) saturation level of ettringite, and 3) dynamic modulus. Various models were utilized to estimate the macroscopic tensile stress in CSA cement

  18. Ageing management and Long-term operation of NPP structures and components

    International Nuclear Information System (INIS)

    The paper presents methodological aspects for ageing management and long-term operation of NPP structures and components considering experience accumulated in nuclear area of Ukraine and IAEA recommendations. The research shows the role of ageing management for lifetime extension and justification of long-term operation of NPP structures and components. The given information is recommended to be used during development of regulatory and technical documents on ageing management and long-term operation

  19. Conservation of acquired morphology and community structure in aged biofilms after facing environmental stress.

    Science.gov (United States)

    Saur, T; Escudié, R; Santa-Catalina, G; Bernet, N; Milferstedt, K

    2016-01-01

    The influence of growth history on biofilm morphology and microbial community structure is poorly studied despite its important role for biofilm development. Here, biofilms were exposed to a change in hydrodynamic conditions at different growth stages and we observed how biofilm age affected the change in morphology and bacterial community structure. Biofilms were developed in two bubble column reactors, one operated under constant shear stress and one under variable shear stress. Biofilms were transferred from one reactor to the other at different stages in their development by withdrawing and inserting the support medium from one reactor to the other. The developments of morphology and microbial community structure were followed by image analysis and molecular tools. When transferred early in biofilm development, biofilms adapted to the new hydrodynamic conditions and adopted features of the biofilm already developed in the receiving reactor. Biofilms transferred at a late state of biofilm development continued their initial trajectories of morphology and community development even in a new environment. These biofilms did not immediately adapt to their new environment and kept features acquired during their early growth phase, a property we called memory effect.

  20. Observations on morphologic changes in the aging and degenerating human disc: Secondary collagen alterations

    Directory of Open Access Journals (Sweden)

    Hanley Edward N

    2002-03-01

    Full Text Available Abstract Background In the annulus, collagen fibers that make up the lamellae have a wavy, planar crimped pattern. This crimping plays a role in disc biomechanical function by allowing collagen fibers to stretch during compression. The relationship between morphologic changes in the aging/degenerating disc and collagen crimping have not been explored. Methods Ultrastructural studies were performed on annulus tissue from 29 control (normal donors (aged newborn to 79 years and surgical specimens from 49 patients (aged 16 to 77 years. Light microscopy and specialized image analysis to visualize crimping was performed on additional control and surgical specimens. Human intervertebral disc tissue from the annulus was obtained in a prospective morphologic study of the annulus. Studies were approved by the authors' Human Subjects Institutional Review Board. Results Three types of morphologic changes were found to alter the crimping morphology of collagen: 1 encircling layers of unusual matrix disrupted the lamellar collagen architecture; 2 collagen fibers were reduced in amount, and 3 collagen was absent in regions with focal matrix loss. Conclusions Although proteoglycan loss is well recognized as playing a role in the decreased shock absorber function of the aging/degenerating disc, collagen changes have received little attention. This study suggests that important stretch responses of collagen made possible by collagen crimping may be markedly altered by morphologic changes during aging/degeneration and may contribute to the early tissue changes involved in annular tears.

  1. Oxidative stress and age-related changes in T cells: is thalassemia a model of accelerated immune system aging?

    Science.gov (United States)

    Ghatreh-Samani, Mahdi; Esmaeili, Nafiseh; Soleimani, Masoud; Asadi-Samani, Majid; Ghatreh-Samani, Keihan; Shirzad, Hedayatolah

    2016-01-01

    Iron overload in β-thalassemia major occurs mainly due to blood transfusion, an essential treatment for β-thalassemia major patients, which results in oxidative stress. It has been thought that oxidative stress causes elevation of immune system senescent cells. Under this condition, cells normally enhance in aging, which is referred to as premature immunosenescence. Because there is no animal model for immunosenescence, most knowledge on the immunosenescence pattern is based on induction of immunosenescence. In this review, we describe iron overload and oxidative stress in β-thalassemia major patients and how they make these patients a suitable human model for immunosenescence. We also consider oxidative stress in some kinds of chronic virus infections, which induce changes in the immune system similar to β-thalassemia major. In conclusion, a therapeutic approach used to improve the immune system in such chronic virus diseases, may change the immunosenescence state and make life conditions better for β-thalassemia major patients.

  2. Mixing in age-structured population models of infectious diseases.

    Science.gov (United States)

    Glasser, John; Feng, Zhilan; Moylan, Andrew; Del Valle, Sara; Castillo-Chavez, Carlos

    2012-01-01

    Infectious diseases are controlled by reducing pathogen replication within or transmission between hosts. Models can reliably evaluate alternative strategies for curtailing transmission, but only if interpersonal mixing is represented realistically. Compartmental modelers commonly use convex combinations of contacts within and among groups of similarly aged individuals, respectively termed preferential and proportionate mixing. Recently published face-to-face conversation and time-use studies suggest that parents and children and co-workers also mix preferentially. As indirect effects arise from the off-diagonal elements of mixing matrices, these observations are exceedingly important. Accordingly, we refined the formula published by Jacquez et al. [19] to account for these newly-observed patterns and estimated age-specific fractions of contacts with each preferred group. As the ages of contemporaries need not be identical nor those of parents and children to differ by exactly the generation time, we also estimated the variances of the Gaussian distributions with which we replaced the Kronecker delta commonly used in theoretical studies. Our formulae reproduce observed patterns and can be used, given contacts, to estimate probabilities of infection on contact, infection rates, and reproduction numbers. As examples, we illustrate these calculations for influenza based on "attack rates" from a prospective household study during the 1957 pandemic and for varicella based on cumulative incidence estimated from a cross-sectional serological survey conducted from 1988-94, together with contact rates from the several face-to-face conversation and time-use studies. Susceptibility to infection on contact generally declines with age, but may be elevated among adolescents and adults with young children. PMID:22037144

  3. Nanoscale Structure, Dynamics, and Aging Behavior of Metallic Glass Thin Films

    Science.gov (United States)

    Burgess, J. A. J.; Holt, C. M. B.; Luber, E. J.; Fortin, D. C.; Popowich, G.; Zahiri, B.; Concepcion, P.; Mitlin, D.; Freeman, M. R.

    2016-08-01

    Scanning tunnelling microscopy observations resolve the structure and dynamics of metallic glass Cu100‑xHfx films and demonstrate scanning tunnelling microscopy control of aging at a metallic glass surface. Surface clusters exhibit heterogeneous hopping dynamics. Low Hf concentration films feature an aged surface of larger, slower clusters. Argon ion-sputtering destroys the aged configuration, yielding a surface in constant fluctuation. Scanning tunnelling microscopy can locally restore the relaxed state, allowing for nanoscale lithographic definition of aged sections.

  4. Nanoscale Structure, Dynamics, and Aging Behavior of Metallic Glass Thin Films

    Science.gov (United States)

    Burgess, J. A. J.; Holt, C. M. B.; Luber, E. J.; Fortin, D. C.; Popowich, G.; Zahiri, B.; Concepcion, P.; Mitlin, D.; Freeman, M. R.

    2016-01-01

    Scanning tunnelling microscopy observations resolve the structure and dynamics of metallic glass Cu100−xHfx films and demonstrate scanning tunnelling microscopy control of aging at a metallic glass surface. Surface clusters exhibit heterogeneous hopping dynamics. Low Hf concentration films feature an aged surface of larger, slower clusters. Argon ion-sputtering destroys the aged configuration, yielding a surface in constant fluctuation. Scanning tunnelling microscopy can locally restore the relaxed state, allowing for nanoscale lithographic definition of aged sections. PMID:27498698

  5. Nanoscale Structure, Dynamics, and Aging Behavior of Metallic Glass Thin Films.

    Science.gov (United States)

    Burgess, J A J; Holt, C M B; Luber, E J; Fortin, D C; Popowich, G; Zahiri, B; Concepcion, P; Mitlin, D; Freeman, M R

    2016-08-08

    Scanning tunnelling microscopy observations resolve the structure and dynamics of metallic glass Cu100-xHfx films and demonstrate scanning tunnelling microscopy control of aging at a metallic glass surface. Surface clusters exhibit heterogeneous hopping dynamics. Low Hf concentration films feature an aged surface of larger, slower clusters. Argon ion-sputtering destroys the aged configuration, yielding a surface in constant fluctuation. Scanning tunnelling microscopy can locally restore the relaxed state, allowing for nanoscale lithographic definition of aged sections.

  6. End plate marrow changes in the asymptomatic lumbosacral spine: frequency, distribution and correlation with age and degenerative changes

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Christine B. [Department of Radiology, VA Healthcare System, 3350 La Jolla Village Drive, CA 92161, La Jolla (United States); Vande Berg, Bruno C.; Malghem, Jacques [Department of Radiology, Cliniques Universitaires St Luc Universite Catholique de Louvain, 10 av Hippocrate, 1200, Brussels (Belgium); Tavernier, Thierry [Service de Radiologie, Clinique de la Sauvegarde, Av David Ben Gourion, 69009, Lyon (France); Cotten, Anne [Service de Radiologie Osteoarticulaire, Hopital R Salengro, 59037, Lille Cedex (France); Laredo, Jean-Denis [Service de Radiologie Osteo-articulaire, Hopital Lariboisiere, 2 rue Ambroise Pare, 75475, Paris Cedex 10 (France); Vallee, Christian [Service d' imagerie medicale, Hopital Raymond Poincare, 104 Boulevard R.Poincare, 92380, Garches (France)

    2004-07-01

    To investigate the frequency and distribution of end plate marrow signal intensity changes in an asymptomatic population and to correlate these findings with patient age and degenerative findings in the spine. MR imaging studies of the lumbosacral (LS) spine in 59 asymptomatic subjects were retrospectively reviewed by 2 musculoskeletal radiologists to determine the presence and location of fat-like and edema-like marrow signal changes about the end plates of the L1-2 through L5-S1 levels. The presence of degenerative changes in the spine was recorded as was patient age. Descriptive statistics were utilized to determine the frequency and associations of end plate findings and degenerative changes in the spine. Interobserver variability was determined by a kappa score. Binomial probability was used to predict the prevalence of the end plate changes in a similar subject population. The Fisher exact test was performed to determine statistical significance of the relationship of end plate changes with degenerative changes in the spine, superior versus inferior location about the disc and age of the patient population. Focal fat-like signal intensity adjacent to the vertebral end-plate was noted in 15 out of 59 subjects by both readers, and involved 38 and 36 out of 590 end plates by readers 1 and 2, respectively. Focal edema-like signal intensity adjacent to the vertebral end plate was noted in 8 out of 59 subjects by both readers and involved 11 and 10 out of 590 end plates by readers 1 and 2, respectively. Either fat or edema signal intensity occurred most often at the anterior (p<.05) aspects of the mid-lumbar spine and was seen in an older sub-population of the study (p<.05). End plate marrow signal intensity changes are present in the lumbar spine of some asymptomatic subjects with a characteristic location along the spine and in vertebral end plates. (orig.)

  7. Structural change in the brazilian economy in the 2000s

    Directory of Open Access Journals (Sweden)

    Alexandre Messa

    2013-12-01

    Full Text Available This paper investigates the sources of structural change in the Brazilian economy in the 2000s. On that purpose, it uses the input-output structural decomposition analysis and introduces a method to correct the influence of prices on the time behavior of the technical coefficients, making them actually represent changes in the production structure. Results show that most of the growth differential between services and industry in that period was induced by the production structure: more precisely, by a lower intermediate consumption of domestic industrial inputs by the production chain of all economic sectors, concomitant with a higher intermediate consumption of services.

  8. Environmental Changes and Social Vulnerability in an Ageing Society: Portugal in the Transition from the 20th to the 21st Centuries

    Directory of Open Access Journals (Sweden)

    Maria João Guardado Moreira

    2010-11-01

    Full Text Available One of the main structural changes human societies are actually facing relies on demographic ageing process, with strong impacts on health system and quality of life. Social and environmental factors can be used as predictors for health conditions, functional and cognitive autonomy, wellbeing and satisfaction on older ages. Reduced incomes, low educational level, situation of loneliness, can also be pointed as predictive factors of a major and premature deterioration of health. The adaptation of social structures must be a priority for all ageing societies. Portugal will also have to find answers to these challenges. The main objective of this study is to understand the process of vulnerability and multiple dependency situations caused by changes in the Portuguese demographic structure, manly regarding old people, as concerns the following aspects: a levels of well-being in ageing regions determined by a statistical indicator; b specific health care and long-term care.

  9. Two Decades of Stability and Change in Age at First Union Formation.

    Science.gov (United States)

    Manning, Wendy D; Brown, Susan L; Payne, Krista K

    2014-04-01

    The landscape of union formation has been shifting; Americans are now marrying at the highest ages on record and the majority of young adults have cohabited. Yet little attention has been paid to the timing of cohabitation relative to marriage. Using the National Survey of Families and Households and 4 cycles of the National Survey of Family Growth, the authors examined the timing of marriage, cohabitation, and unions over 20 years. As the median age at first marriage has climbed, the age at cohabitation has remained stable for men and women. The changes in the timing of union formation have been similar according to race/ethnicity. The marked delay in marriage among women and men with low educational attainment has resulted in a near-convergence in the age at first marriage according to education. The authors conclude that the rise in cohabitation has offset changes in the levels and timing of marriage.

  10. Age-related changes in kynurenic acid production in rat brain

    DEFF Research Database (Denmark)

    Gramsbergen, J B; Schmidt, W; Turski, W A;

    1992-01-01

    -dependent increase of KYNA concentration in brain tissue, suggest an enhanced KYNA tone in the aged brain. Together with the reported decline in cerebral excitatory amino acid receptor densities with age, increased production of KYNA may play a role in cognitive and memory dysfunction in old animals....... investigated in tissue slices and was found to be significantly enhanced in the cortex and hippocampus of old animals. The effect of depolarizing agents or sodium replacement was virtually identical in tissues from young and old rats. These data, which are in excellent agreement with reports on an age...... months of age in all five brain regions examined. No changes were observed in the liver. The changes were particularly pronounced in the cortex and in the striatum where enzyme activity increased three-fold during the period studied. KYNA production from its bioprecursor L-kynurenine was also...

  11. Intrinsic Age-Dependent Changes and Cell-Cell Contacts Regulate Nephron Progenitor Lifespan.

    Science.gov (United States)

    Chen, Shuang; Brunskill, Eric W; Potter, S Steven; Dexheimer, Phillip J; Salomonis, Nathan; Aronow, Bruce J; Hong, Christian I; Zhang, Tongli; Kopan, Raphael

    2015-10-12

    During fetal development, nephrons of the metanephric kidney form from a mesenchymal progenitor population that differentiates en masse before or shortly after birth. We explored intrinsic and extrinsic mechanisms controlling progenitor lifespan in a transplantation assay that allowed us to compare engraftment of old and young progenitors into the same young niche. The progenitors displayed an age-dependent decrease in proliferation and concomitant increase in niche exit rates. Single-cell transcriptome profiling revealed progressive age-dependent changes, with heterogeneity increasing in older populations. Age-dependent elevation in mTor and reduction in Fgf20 could contribute to increased exit rates. Importantly, 30% of old progenitors remained in the niche for up to 1 week post engraftment, a net gain of 50% to their lifespan, but only if surrounded by young neighbors. We provide evidence in support of a model in which intrinsic age-dependent changes affect inter-progenitor interactions that drive cessation of nephrogenesis. PMID:26460946

  12. Two Decades of Stability and Change in Age at First Union Formation.

    Science.gov (United States)

    Manning, Wendy D; Brown, Susan L; Payne, Krista K

    2014-04-01

    The landscape of union formation has been shifting; Americans are now marrying at the highest ages on record and the majority of young adults have cohabited. Yet little attention has been paid to the timing of cohabitation relative to marriage. Using the National Survey of Families and Households and 4 cycles of the National Survey of Family Growth, the authors examined the timing of marriage, cohabitation, and unions over 20 years. As the median age at first marriage has climbed, the age at cohabitation has remained stable for men and women. The changes in the timing of union formation have been similar according to race/ethnicity. The marked delay in marriage among women and men with low educational attainment has resulted in a near-convergence in the age at first marriage according to education. The authors conclude that the rise in cohabitation has offset changes in the levels and timing of marriage. PMID:25147410

  13. Biological implications of longevity in dairy cows: 2. Changes in methane emissions and efficiency with age.

    Science.gov (United States)

    Grandl, F; Amelchanka, S L; Furger, M; Clauss, M; Zeitz, J O; Kreuzer, M; Schwarm, A

    2016-05-01

    Previous studies indicated that absolute CH4 emissions and CH4 yield might increase and that milk production efficiency might decrease with age in cattle. Both would make strategies to increase longevity in dairy cattle less attractive. These aspects were experimentally determined in Brown Swiss cattle distributed continuously across a large age range. Thirty lactating dairy cows (876-3,648 d of age) received diets consisting of hay, corn silage, and grass pellets supplemented with 0 or 5kg of concentrate per day. Twelve heifers (199-778 d of age) received hay only. Cows and heifers were members of herds subjected to the 2 different feeding regimens (with or without concentrate) for the past 10 yr. Methane emissions were measured individually for 2 d in open-circuit respiration chambers, followed by quantifying individual feed intake and milk yield over 8 d. Additional data on digestibility, rumination time, and passage time of feed of all experimental animals were available. Regression analyses were applied to evaluate effects of age and feeding regimen. Body weight, milk yield, and the hay proportion of forage dry matter intake were considered as covariates. Methane emissions per unit of intake, body weight, and milk yield were significantly related to age. Their development in the cows with age was characterized by an increase to maximum at around 2,000 d of age, followed by a decline. This response was not accompanied by corresponding age-related changes in intake, chewing activity, digesta passage time, and digestibility of organic matter, which would have explained shifts in CH4. However, fiber digestibility showed a similar change with age as methane emissions, resulting in quite stable methane emissions per unit of digestible fiber. As expected, methane emissions intensity per unit of milk produced was greater by 8% without concentrate than with concentrate, but no difference was noted in the response to age when the animals were subjected to different

  14. Changes in the axonal conduction velocity of pyramidal tract neurons in the aged cat.

    Science.gov (United States)

    Xi, M C; Liu, R H; Engelhardt, J K; Morales, F R; Chase, M H

    1999-01-01

    The present study was undertaken to determine whether age-dependent changes in axonal conduction velocity occur in pyramidal tract neurons. A total of 260 and 254 pyramidal tract neurons were recorded extracellularly in the motor cortex of adult control and aged cats, respectively. These cells were activated antidromically by electrical stimulation of the medullary pyramidal tract. Fast- and slow-conducting neurons were identified according to their axonal conduction velocity in both control and aged cats. While 51% of pyramidal tract neurons recorded in the control cats were fast conducting (conduction velocity greater than 20 m/s), only 26% of pyramidal tract neurons in the aged cats were fast conducting. There was a 43% decrease in the median conduction velocity for the entire population of pyramidal tract neurons in aged cats when compared with that of pyramidal tract neurons in the control cats (P cats. However, the regression slope was significantly reduced in aged cats. This reduction was due to the appearance of a group of pyramidal tract neurons with relatively shorter spike durations but slower axonal conduction velocities in the aged cat. Sample intracellular data confirmed the above results. These observations form the basis for the following conclusions: (i) there is a decrease in median conduction velocity of pyramidal tract neurons in aged cats; (ii) the reduction in the axonal conduction velocity of pyramidal tract neurons in aged cats is due, in part, to fibers that previously belonged to the fast-conducting group and now conduct at slower velocity. PMID:10392844

  15.  Age-related changes of skeletal muscles: physiology, pathology and regeneration

    Directory of Open Access Journals (Sweden)

    Aleksandra Ławniczak

    2012-06-01

    Full Text Available  This review provides a short presentation of the aging-related changes of human skeletal muscles. The aging process is associated with the loss of skeletal muscle mass (sarcopenia and strength. This results from fibre atrophy and apoptosis, decreased regeneration capacity, mitochondrial dysfunction, gradual reduction of the number of spinal cord motor neurons, and local and systemic metabolic and hormonal alterations. The latter involve age-related decrease of the expression and activity of some mitochondrial and cytoplasmic enzymes, triacylglycerols and lipofuscin accumulation inside muscle fibres, increased proteolytic activity, insulin resistance and decreased serum growth hormone and IGF-1 concentrations. Aging of the skeletal muscles is also associated with a decreased number of satellite cells and their proliferative activity. The age-related reduction of skeletal muscle mass and function may be partially prevented by dietary restriction and systematic physical exercises.

  16. Mechanical and morphological evaluation of age-related changes in the Beagle spine

    International Nuclear Information System (INIS)

    Age-related changes were evaluated in the spines of Beagle dogs by biomechanical testing, radiology and pathology. Thirty age-matched healthy Beagle dogs were divided into five groups having mean ages of 2, 5, 8, 11, and 14 years. Spinal radiographs of anesthetized dogs were taken prior to euthanasia and on defleshed pines following necropsy. Cervical, thoracic, and lumbar segments were tested in compression to calculate peak stress, peak strain, and elastic modulus. Adjacent spinal segments were examined histologically. Histological evidence of the disc degeneration and changes in the mechanical properties of the intervertebral disc joint preceded radiographical evidence of spondylosis. Changes in the mechanical properties of the disc space were probably a result of the disc degeneration rather than the spondylytic lesions. 3 references, 4 figures

  17. What will 1984 be like? Socioeconomic implications of recent twists in age structure.

    Science.gov (United States)

    Easterlin, R A

    1978-11-01

    Since 1940, under conditions of restricted immigration and high and sustained growth in aggregate demand, shifts in the relative number of younger versus older adults have had a pervasive impact on American life. Before 1960, younger males were in increasingly short supply and their relative economic position substantially improved; after 1960, the opposite was true. Since the early sixties, as the relative condition of young adults has deteriorated, marriage has been increasingly deferred and fertility reduced. The labor force participation of young women has risen at above average rates, and that of older women has risen at below average rates. Changes in the age structure of the working age population have also contributed to a combination of rising unemployment and accelerating inflation. Cohort divorce rates, suicide among young males, crime rates, and political alienation have worsened. The rise in college enrollment rates has been interrupted, and SAT scores have declined. In contrast, in the period 1940-1960, changes in these various magnitudes were typically of a more favorable sort. The United States is now at the start of a new period of growing scarcity of young adults as a result of the birth rate decline that set in after 1960. This implies that the 1980s will see a turnaround or amelioration in a wide variety of these social, political, and economic conditions, some of which have been taken as symptomatic of a hardening social malaise. PMID:738471

  18. Dynamic Changes in Sarcoplasmic Reticulum Structure in Ventricular Myocytes

    Directory of Open Access Journals (Sweden)

    Amanda L. Vega

    2011-01-01

    sarcoplasmic reticulum (SR and the sarcolemma where Ca2+ release is activated. Here, we tested the hypothesis that the SR is a structurally inert organelle in ventricular myocytes. Our data suggest that rather than being static, the SR undergoes frequent dynamic structural changes. SR boutons expressing functional ryanodine receptors moved throughout the cell, approaching or moving away from the sarcolemma of ventricular myocytes. These changes in SR structure occurred in the absence of changes in [Ca2+] during EC coupling. Microtubules and the molecular motors dynein and kinesin 1(Kif5b were important regulators of SR motility. These findings support a model in which the SR is a motile organelle capable of molecular motor protein-driven structural changes.

  19. Age-related changes of the diffusion tensor imaging parameters of the normal cervical spinal cord

    International Nuclear Information System (INIS)

    Highlights: • It is essential to determine the DTI parameters in the whole CSC. • To analyze DTI parameters in all intervertebral space levels of the CSC. • To study the impact of age on these parameters in healthy Chinese subjects. • Provide better insights in factors that could bias the diagnosis of CSC pathologies. - Abstract: Background: The diffusion tensor imaging (DTI) parameters of the cervical spinal cord (CSC) changes with age. However, previous studies only examined specific CSC areas. Objectives: To analyze the DTI parameters in all intervertebral space levels of the whole normal CSC and to study the impact of age on these parameters in a Chinese population. Methods: Thirty-six healthy subjects aged 20–77 years were recruited. DTI parameters were calculated for gray matter (GM) and white matter (WM) funiculi in all the CSC intervertebral spaces (C1/2-C6/7). Age-related changes of DTI parameters were analyzed for the GM and WM funiculi. Results: Fractional anisotropy (FA) and mean diffusivity (MD) were lower in GM than in WM. MD and FA values were lower in the WM in the lower CSC compared with the upper CSC (all P < 0.05), but no difference was observed in GM. In ventral funiculi, MD increased with age, while FA decreased (all P < 0.001). In lateral and dorsal funiculi, MD and FA decreased with age (all P < 0.001). In GM, MD and FA decreased with age (all P < 0.001). Significant age-related changes were observed in FA and MD from GM and WM funiculi. FA was correlated with age in all funiculi (ventral: r = −0.733; lateral: r = −0.468; dorsal: r = −0.607; GM: r = −0.724; all P < 0.01). Conclusion: Important changes in MD and FA were observed with advancing age at all levels of CSC in Chinese patients. DTI parameters may be useful to assess CSC pathology, but the influence of age and segments need to be taken into account in diagnosis

  20. Age-related changes in conventional road versus off-road triathlon performance

    OpenAIRE

    Lepers, Romuald; Stapley, P.J.

    2011-01-01

    International audience The aims of this study were: i) to analyze age-related declines in swimming, cycling, and running performances for road-based and off-road triathlons, and ii) to compare age-related changes in these three disciplines between road-based and off-road triathlons. Swimming, cycling, running and total time performances of the top 5 males between 20 and 70 years of age (in 5 year intervals) were analyzed for short distance road-based (1.5 km swim, 40 km cycle, and 10 km ru...

  1. Effects of age and beta-amyloid on cognitive changes in normal elderly people

    OpenAIRE

    Oh, Hwamee; Madison, Cindee,; Haight, Thaddeus J.; Markley, Candace; Jagust, William J.

    2012-01-01

    Age-related decline is common in multiple cognitive domains. β-amyloid (Aβ) deposition, a pathological hallmark of Alzheimer’s disease, is also associated with cognitive changes in many older people. In this study, we examined a wide range of cognitive function in order to differentiate the effect of age and Aβ on cognition during aging. Using PET imaging with the radiotracer Pittsburgh compound B (PIB), we classified normal older subjects as High PIB-Old and Low PIB-Old and applied sequentia...

  2. Age-related changes of the diffusion tensor imaging parameters of the normal cervical spinal cord

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Kun, E-mail: medsciwangkun@126.com [Orthopedics Department, Changhai Hospital Affiliated to Second Military Medical University, Shanghai (China); Song, Qingxin; Zhang, Fan; Chen, Zhi; Hou, Canglong; Tang, Yixing [Orthopedics Department, Changhai Hospital Affiliated to Second Military Medical University, Shanghai (China); Chen, Shiyue [Radiology Department, Changhai Hospital Affiliated to Second Military Medical University, Shanghai (China); Hao, Qiang, E-mail: haoqiang@189.cn [Radiology Department, Changhai Hospital Affiliated to Second Military Medical University, Shanghai (China); Shen, Hongxing, E-mail: shenhxgk@126.com [Orthopedics Department, Changhai Hospital Affiliated to Second Military Medical University, Shanghai (China)

    2014-12-15

    Highlights: • It is essential to determine the DTI parameters in the whole CSC. • To analyze DTI parameters in all intervertebral space levels of the CSC. • To study the impact of age on these parameters in healthy Chinese subjects. • Provide better insights in factors that could bias the diagnosis of CSC pathologies. - Abstract: Background: The diffusion tensor imaging (DTI) parameters of the cervical spinal cord (CSC) changes with age. However, previous studies only examined specific CSC areas. Objectives: To analyze the DTI parameters in all intervertebral space levels of the whole normal CSC and to study the impact of age on these parameters in a Chinese population. Methods: Thirty-six healthy subjects aged 20–77 years were recruited. DTI parameters were calculated for gray matter (GM) and white matter (WM) funiculi in all the CSC intervertebral spaces (C1/2-C6/7). Age-related changes of DTI parameters were analyzed for the GM and WM funiculi. Results: Fractional anisotropy (FA) and mean diffusivity (MD) were lower in GM than in WM. MD and FA values were lower in the WM in the lower CSC compared with the upper CSC (all P < 0.05), but no difference was observed in GM. In ventral funiculi, MD increased with age, while FA decreased (all P < 0.001). In lateral and dorsal funiculi, MD and FA decreased with age (all P < 0.001). In GM, MD and FA decreased with age (all P < 0.001). Significant age-related changes were observed in FA and MD from GM and WM funiculi. FA was correlated with age in all funiculi (ventral: r = −0.733; lateral: r = −0.468; dorsal: r = −0.607; GM: r = −0.724; all P < 0.01). Conclusion: Important changes in MD and FA were observed with advancing age at all levels of CSC in Chinese patients. DTI parameters may be useful to assess CSC pathology, but the influence of age and segments need to be taken into account in diagnosis.

  3. Sex-specific age-related changes of information processing rate indicators during childhood and adolescence.

    Science.gov (United States)

    Zebec, Mislav S; Budimir, Sanja; Merkas, Marina; Szirovicza, Lajos; Zivicnjak, Miroslav

    2014-06-01

    Despite the relevant findings on non-average information processing rate (IPR) indicators-intelligence relation, and on age-related changes of some of these indicators during aging, the research on sex-specific age-related changes of these indicators during childhood and adolescence are lacking. In a transversal study, 1197 school children (598 girls) aged 8-18 have been individually measured on 5 IPR indicators--two averages (mean_t, median_t) and three non-averages (min_t, max_t, sd_t). The results corroborated the expected non-linear changes of average IPR indicators in the observed developmental period, whereby the sex difference in related developmental patterns was detected: marked age-related decrement in girls ceased at the age of 12, and in boys around the age of 13-14, after which progress in both sexes gradually ceased by the age of 18 and was less pronounced in girls. Generally similar non-linear age-related decrements of non-average indicators were registered, but they showed mutual intensity differences at specific ages and sex difference in developmental patterns was detected, analogously to average indicators. Systematic sex differences in the whole observed period were obtained only in two non-average indicators: girls showed minor sd_t and boys showed minor min_t. In specific age groups, a number of sex differences were obtained that are explainable by two possible mechanisms: earlier maturation in girls and sex bias of the IPR task content. The justifiability of separate, average and non-average, IPR indicators application was corroborated by their distribution form differences, by mutual, predominantly low and medium correlations, by the different intensity of their developmental changes and by their different ability to detect sex differences. For all registered phenomena, the theoretical and/or empirical explanations were offered from the domain of sex specific intellectual, motor and neural development, and it has been shown that non

  4. Physical aging and structural recovery in a colloidal glass subjected to volume-fraction jump conditions.

    Science.gov (United States)

    Peng, Xiaoguang; McKenna, Gregory B

    2016-04-01

    Three important kinetic phenomena have been cataloged by Kovacs in the investigation of molecular glasses during structural recovery or physical aging. These are responses to temperature-jump histories referred to as intrinsic isotherms, asymmetry of approach, and memory effect. Here we use a thermosensitive polystyrene-poly (N-isopropylacrylamide)-poly (acrylic acid) core-shell particle-based dispersion as a colloidal model and by working at a constant number concentration of particles we use temperature changes to create volume-fraction changes. This imposes conditions similar to those defined by Kovacs on the colloidal system. We use creep experiments to probe the physical aging and structural recovery behavior of colloidal glasses in the Kovacs-type histories and compare the results with those seen in molecular glasses. We find that there are similarities in aging dynamics between molecular glasses and colloidal glasses, but differences also persist. For the intrinsic isotherms, the times t_{eq} needed for relaxing or evolving into the equilibrium (or stationary) state are relatively insensitive to the volume fraction and the values of t_{eq} are longer than the α-relaxation time τ_{α} at the same volume fraction. On the other hand, both of these times grow at least exponentially with decreasing temperature in molecular glasses. For the asymmetry of approach, similar nonlinear behavior is observed for both colloidal and molecular glasses. However, the equilibration time t_{eq} is the same for both volume-fraction up-jump and down-jump experiments, different from the finding in molecular glasses that it takes longer for the structure to evolve into equilibrium for the temperature up-jump condition than for the temperature down-jump condition. For the two-step volume-fraction jumps, a memory response is observed that is different from observations of structural recovery in two-step temperature histories in molecular glasses. The concentration dependence of the

  5. Transcriptome analysis of murine thymocytes reveals age-associated changes in thymic gene expression

    Directory of Open Access Journals (Sweden)

    Ana Lustig, Arnell Carter, Dorothy Bertak, Divya Enika, Bolormaa Vandanmagsar, William Wood, Kevin G. Becker, Ashani T. Weeraratna, Dennis D. Taub

    2009-01-01

    Full Text Available The decline in adaptive immunity, naïve T-cell output and a contraction in the peripheral T cell receptor (TCR repertoire with age are largely attributable to thymic involution and the loss of critical cytokines and hormones within the thymic microenvironment. To assess the molecular changes associated with this loss of thymic function, we used cDNA microarray analyses to examine the transcriptomes of thymocytes from mice of various ages ranging from very young (1 month to very old (24 months. Genes associated with various biological and molecular processes including oxidative phosphorylation, T- and B- cell receptor signaling and antigen presentation were observed to significantly change with thymocyte age. These include several immunoglobulin chains, chemokine and ribosomal proteins, annexin A2, vav 1 and several S100 signaling proteins. The increased expression of immunoglobulin genes in aged thymocytes could be attributed to the thymic B cells which were found to be actively producing IgG and IgM antibodies. Upon further examination, we found that purified thymic T cells derived from aged but not young thymi also exhibited IgM on their cell surface suggesting the possible presence of auto-antibodies on the surface thymocytes with advancing age. These studies provide valuable insight into the cellular and molecular mechanisms associated with thymic aging.

  6. Empirical analysis of structural change in Credit Default Swap volatility

    International Nuclear Information System (INIS)

    The purpose of this paper is to study the structural change in Credit Default Swap volatility. We use statistical properties and a network approach to better understand the behavior of CDS volatility. We hypothesize that structural change occurs in CDS index during a financial crisis and it requires subperiod analysis, rather than full period analysis, to investigate properly. Our results show that the probability of large volatility is related to the structure of volatility but it is more significantly related to the size of volatility. Both the memory property and the size of volatility are confirmed to have dependence on the structure of volatility. The linked degree of CDS volatilities is highly related to the probability of large volatility and its predictability, regardless of structural change in volatility. Another interesting result is that the CDS volatility of a country is more related to the behavior of other volatilities, not the geographical location

  7. Factor structure of functional state of primary school age children

    Directory of Open Access Journals (Sweden)

    Davidenko O.V.

    2011-02-01

    Full Text Available The examination of primary school children to determine the ranking of significant factors that determine the structure of their functional state depending on the level of physical health. It is shown that the main factor in the structure of the functional state of younger schoolchildren in low-and lower-middle level of physical fitness is selected morpho-functional status, which characterizes the functions of the body at rest. For children with average or above average level of physical fitness is a leading factor in physical fitness of schoolchildren.

  8. CT STUDY COMPARING SULCAL CHANGES AND THIRD VENTRICLE SIZE AS AGE PROGRESSES FROM 40 TO 80

    Directory of Open Access Journals (Sweden)

    Vinu C

    2014-09-01

    Full Text Available INTRODUCTION: Computerized tomography, also called CT combines a series of X-ray views taken from many different angles and computer processing to create cross-sectional images of the bones and soft tissues inside your body. It has brought about tremendous changes in the field of diagnostic and research medicine. Here CT is used to measure the various dimensions of 6 selected sulci of brain and third ventricle. With the recent advances in technology, sulcal pattern and development is being studied extensively to understand the functioning of brain. There is evidence of sulcal dimensional changes as age of an individual progress. This may be responsible for behavioral or intellectual changes in a individual. Through this study I intend to understand how the sulcal dimension may vary with the help of CT scans. 6 sulci were selected and their width was measured in 80 individuals between the age group of 40 and 80. Through statistical analysis the data will reveal any recognizable changes in the width of the selected sulcus with progression of age. The third ventricle size may also be influenced by the age of the individual. Using the help of CT scan I am intending to measure the dimensions of the third ventricle. Recent studies have shown that size and volume of the third ventricle have significant role in the geriatric population. AIMS AND OBJECTIVES: To study the age related changes in the width of left and right central sulcus, superior temporal sulcus, parieto-occipital sulcus and to study the age related changes in third ventricle depth, length and width through the use of CT scans. STUDY SETTINGS: A cross-sectional study comprising of 60 patients coming to the radiology department for the C T scan. The CT scans for the study were taken randomly between the ages of 40 to 80. RESULTS: The purpose of the study was to study the changes in the dimensions of sulci and the third ventricle of the brain. Hypothesis was that the sulcal width increases

  9. Age-dependent changes in β-adrenoceptor function in human detrusors and possible mechanisms

    Institute of Scientific and Technical Information of China (English)

    李刚; 李凯; 李振华; 王平

    2003-01-01

    Objective To study age-dependent changes in β-adrenergic responsiveness and their possible mechanisms.Methods Responsiveness to the β-adrenergic agonists isoprenaline, BRL37344, forskolin, and dibutyryl cyclic AMP (DBcAMP) was examined in samples from 10 older patients by using a cellular function test. A radioligand binding assay was performed using the non-selective β-adrenergic receptor ligand [3H]- dihydroalprenolol ([3H]-DHA). Specimens from 10 young men were used as controls.Results There were no age-dependent changes in contractile response to KCl. The relaxation responses to isoprenaline, BRL37344, and forskolin decreased in the aged group by 15.0%, 17.6%, and 12.6%, respectively (P<0.001). The pD2 values for isoprenaline and BRL37344 also declined significantly. There was no difference in the responsiveness to dibutyryl cyclic AMP (DBcAMP) between the two groups; the maximum binding site decreased significantly with increasing age, but the equilibrium-dissociation constant did not change. Conclusions There is an age-related decline in β-adrenergic responsiveness which might be one of the causative factors of reduced bladder compliance in the elderly. A decrease in cAMP level caused by reduced receptor density and adenylyl cyclase activity might be the underlying molecular mechanism of the changes in β-adrenergic responsiveness.

  10. Age-related changes in thyroid hormone levels of bonobos and chimpanzees indicate heterochrony in development.

    Science.gov (United States)

    Behringer, Verena; Deschner, Tobias; Murtagh, Róisín; Stevens, Jeroen M G; Hohmann, Gottfried

    2014-01-01

    We present information on age related changes of thyroid hormone levels in bonobos (N = 96) and chimpanzees (N = 100) ranging between one and 56 years of age. Fresh urine samples were used for hormone measurements with a commercial competitive total triiodothyronine (T3) ELISA. In both species, immature individuals had higher TT3 levels than adults and there was a marked decrease in TT3 levels between age classes. The two species differed in terms of the timing of TT3 level changes, with chimpanzees experiencing a significant decline in TT3 levels after 10 years of age and bonobos after 20 years of age. The decline of TT3 in chimpanzees appears to coincide with the time when somatic growth terminates while TT3 values in bonobos decrease much later. This temporal asymmetry in urinary thyroid hormone levels indicates heterochrony in the ontogenetic changes of the two sister species and developmental delay in bonobos. The prolongation of high TT3 levels in bonobos, which is characteristic of immatures of both Pan species may affect the behavior of bonobos; namely, the low intensity of aggression they display. Given that developmental studies are often based on post-mortem analyses of skeletons, measures of urinary thyroid hormones offer a non-invasive tool for exploring ontogenetic changes in living wild and captive hominoids. PMID:24275194

  11. Age-Associated Changes in the Spectral and Statistical Parameters of Surface Electromyogram of Tibialis Anterior.

    Science.gov (United States)

    Siddiqi, Ariba; Arjunan, Sridhar Poosapadi; Kumar, Dinesh Kant

    2016-01-01

    Age-related neuromuscular change of Tibialis Anterior (TA) is a leading cause of muscle strength decline among the elderly. This study has established the baseline for age-associated changes in sEMG of TA at different levels of voluntary contraction. We have investigated the use of Gaussianity and maximal power of the power spectral density (PSD) as suitable features to identify age-associated changes in the surface electromyogram (sEMG). Eighteen younger (20-30 years) and 18 older (60-85 years) cohorts completed two trials of isometric dorsiflexion at four different force levels between 10% and 50% of the maximal voluntary contraction. Gaussianity and maximal power of the PSD of sEMG were determined. Results show a significant increase in sEMG's maximal power of the PSD and Gaussianity with increase in force for both cohorts. It was also observed that older cohorts had higher maximal power of the PSD and lower Gaussianity. These age-related differences observed in the PSD and Gaussianity could be due to motor unit remodelling. This can be useful for noninvasive tracking of age-associated neuromuscular changes. PMID:27610379

  12. Structural Changes and Global Trends in European Union Trade

    OpenAIRE

    Ishak Mesic

    2009-01-01

    The article aims at researching and presenting structural changes and global trends in distributive trade of European Union, resulted from liberalization of economic activities within the EU. During the last decades, EU trade went through deep transformation and structural changes. Traditional distributive trade has been replaced by organized and concentrated distribution. Even though, there are many developing trends which unify the EU trade, still there are some differences specific for par...

  13. Stress reduction correlates with structural changes in the amygdala

    OpenAIRE

    Hölzel, Britta K.; Carmody, James; Evans, Karleyton C.; Hoge, Elizabeth A.; Dusek, Jeffery A; Morgan, Lucas; Pitman, Roger K.; Lazar, Sara W.

    2009-01-01

    Stress has significant adverse effects on health and is a risk factor for many illnesses. Neurobiological studies have implicated the amygdala as a brain structure crucial in stress responses. Whereas hyperactive amygdala function is often observed during stress conditions, cross-sectional reports of differences in gray matter structure have been less consistent. We conducted a longitudinal MRI study to investigate the relationship between changes in perceived stress with changes in amygdala ...

  14. Measurement of choroid plexus perfusion using dynamic susceptibility MR imaging: capillary permeability and age-related changes

    Energy Technology Data Exchange (ETDEWEB)

    Bouzerar, Roger; Chaarani, Bader; Baledent, Olivier [University Hospital, Image Processing Department, Amiens (France); Gondry-Jouet, Catherine [University Hospital, Radiology Department, Amiens (France); Zmudka, Jadwiga [University Hospital, Geriatric Unit, Amiens (France)

    2013-12-15

    The cerebrospinal fluid (CSF) plays a major role in the physiology of the central nervous system. The continuous turnover of CSF is mainly attributed to the highly vascularized choroid plexus (CP) located in the cerebral ventricles which represent a complex interface between blood and CSF. We propose a method for evaluating CP functionality in vivo using perfusion MR imaging and establish the age-related changes of associated parameters. Fifteen patients with small intracranial tumors were retrospectively studied. MR Imaging was performed on a 3T MR Scanner. Gradient-echo echo planar images were acquired after bolus injection of gadolinium-based contrast agent (CA). The software developed used the combined T1- and T2-effects. The decomposition of the relaxivity signals enables the calculation of the CP capillary permeability (K{sub 2}). The relative cerebral blood volume (rCBV), mean transit time (MTT), and signal slope decrease (SSD) were also calculated. The mean permeability K{sub 2} of the extracted CP was 0.033+/-0.18 s{sup -1}. K{sub 2} and SSD significantly decreased with subject's age whereas MTT significantly increased with subject's age. No significant correlation was found for age-related changes in rCBV and rCBF. The decrease in CP permeability is in line with the age-related changes in CSF secretion observed in animals. The MTT increase indicates significant structural changes corroborated by microscopy studies in animals or humans. Overall, DSC MR-perfusion enables an in vivo evaluation of the hemodynamic state of CP. Clinical applications such as neurodegenerative diseases could be considered thanks to specific functional studies of CP. (orig.)

  15. Changes in social relations in old age. Are they influenced by functional ability?

    DEFF Research Database (Denmark)

    Avlund, Kirsten; Due, Pernille; Holstein, Bjørn Evald;

    2002-01-01

    The aims of this article were to describe changes in social relations from ages 75 to 80, and analyze whether changes in social relations are influenced by functional ability at age 75. The study includes data from the NORA follow-up study of 75-80 year-old men and women in Jyväskylä (Finland......, close friends, acquaintances, and neighbors; 2) diversity of social relations (number of types of social contacts); 3) telephone contacts; and 4) social participation. The function of social relations was measured by instrumental social support. Functional ability was measured by tiredness and need for...

  16. Chromatin Structure in Cell Differentiation, Aging and Cancer

    NARCIS (Netherlands)

    S. Kheradmand Kia (Sima)

    2009-01-01

    textabstractChromatin is the structure that the eukaryotic genome is packaged into, allowing over a metre of DNA to fit into the small volume of the nucleus. It is composed of DNA and proteins, most of which are histones. This DNA-protein complex is the template for a number of essential cell proces

  17. Structural changes of linear DNA molecules induced by cisplatin

    International Nuclear Information System (INIS)

    Interaction between long DNA molecules and activated cisplatin is believed to be crucial to anticancer activity. However, the exact structural changes of long DNA molecules induced by cisplatin are still not very clear. In this study, structural changes of long linear double-stranded DNA (dsDNA) and short single-stranded DNA (ssDNA) induced by activated cisplatin have been investigated by atomic force microscopy (AFM). The results indicated that long DNA molecules gradually formed network structures, beads-on-string structures and their large aggregates. Electrostatic and coordination interactions were considered as the main driving forces producing these novel structures. An interesting finding in this study is the beads-on-string structures. Moreover, it is worth noting that the beads-on-string structures were linked into the networks, which can be ascribed to the strong DNA–DNA interactions. This study expands our knowledge of the interactions between DNA molecules and cisplatin. - Highlights: • We investigate structural changes of dsDNA and ssDNA induced by cisplatin. • AFM results indicated long dsDNA formed network, beads-on-string and aggregates. • ssDNA can form very similar structures as those of long linear dsDNA. • A possible formation process of theses novel structure is proposed

  18. Structural changes of linear DNA molecules induced by cisplatin

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhiguo, E-mail: cn.zguoliu@yahoo.com [State Engineering Laboratory of Bio-Resource Eco-Utilization, Harbin 150040 (China); Engineering Research Center of Forest Bio-preparation, Ministry of Education, Northeast Forestry University, Harbin 150040 (China); Key Laboratory of Forest Plant Ecology of Ministry of Education, Northeast Forestry University, Harbin 150040 (China); Liu, Ruisi; Zhou, Zhen; Zu, Yuangang; Xu, Fengjie [State Engineering Laboratory of Bio-Resource Eco-Utilization, Harbin 150040 (China); Engineering Research Center of Forest Bio-preparation, Ministry of Education, Northeast Forestry University, Harbin 150040 (China); Key Laboratory of Forest Plant Ecology of Ministry of Education, Northeast Forestry University, Harbin 150040 (China)

    2015-02-20

    Interaction between long DNA molecules and activated cisplatin is believed to be crucial to anticancer activity. However, the exact structural changes of long DNA molecules induced by cisplatin are still not very clear. In this study, structural changes of long linear double-stranded DNA (dsDNA) and short single-stranded DNA (ssDNA) induced by activated cisplatin have been investigated by atomic force microscopy (AFM). The results indicated that long DNA molecules gradually formed network structures, beads-on-string structures and their large aggregates. Electrostatic and coordination interactions were considered as the main driving forces producing these novel structures. An interesting finding in this study is the beads-on-string structures. Moreover, it is worth noting that the beads-on-string structures were linked into the networks, which can be ascribed to the strong DNA–DNA interactions. This study expands our knowledge of the interactions between DNA molecules and cisplatin. - Highlights: • We investigate structural changes of dsDNA and ssDNA induced by cisplatin. • AFM results indicated long dsDNA formed network, beads-on-string and aggregates. • ssDNA can form very similar structures as those of long linear dsDNA. • A possible formation process of theses novel structure is proposed.

  19. [Changes in olfaction during ageing and in certain neurodegenerative diseases: up-to-date].

    Science.gov (United States)

    Bianchi, A-J; Guépet-Sordet, H; Manckoundia, P

    2015-01-01

    Olfaction is a complex sensory system, and increasing interest is being shown in the link between olfaction and cognition, notably in the elderly. In this literature review, we revisit the specific neurophysiological features of the olfactory system and odorants that lead to a durable olfactory memory and an emotional memory, for which the implicit component produces subconscious olfactory conditioning. Olfaction is known to affect cognitive abilities and mood. We also consider the impairment of olfactory function due to ageing and to neurodegenerative diseases, in particular Alzheimer's disease and Parkinson's disease, through anatomopathological changes in the peripheral and central olfactory structures. The high frequency of these olfactory disorders as well as their early occurrence in Alzheimer disease and Parkinson disease are in favour of their clinical detection in subjects suffering from these two neurodegenerative diseases. Finally, we analyse the impact of olfactory stimulation on cognitive performance and attention. Current observational data from studies in elderly patients with Alzheimer-type dementia are limited to multiple sensory stimulation methods, such as the Snoezelen method, and aromatherapy. These therapies have shown benefits for dementia-related mood and behaviour disorders in the short term, with few side effects. Since olfactory chemosensory stimulation may be beneficial, it may be proposed in patients with dementia, especially Alzheimer-type dementia, as a complementary or even alternative therapy to existing medical strategies. PMID:25304170

  20. [Changes in olfaction during ageing and in certain neurodegenerative diseases: up-to-date].

    Science.gov (United States)

    Bianchi, A-J; Guépet-Sordet, H; Manckoundia, P

    2015-01-01

    Olfaction is a complex sensory system, and increasing interest is being shown in the link between olfaction and cognition, notably in the elderly. In this literature review, we revisit the specific neurophysiological features of the olfactory system and odorants that lead to a durable olfactory memory and an emotional memory, for which the implicit component produces subconscious olfactory conditioning. Olfaction is known to affect cognitive abilities and mood. We also consider the impairment of olfactory function due to ageing and to neurodegenerative diseases, in particular Alzheimer's disease and Parkinson's disease, through anatomopathological changes in the peripheral and central olfactory structures. The high frequency of these olfactory disorders as well as their early occurrence in Alzheimer disease and Parkinson disease are in favour of their clinical detection in subjects suffering from these two neurodegenerative diseases. Finally, we analyse the impact of olfactory stimulation on cognitive performance and attention. Current observational data from studies in elderly patients with Alzheimer-type dementia are limited to multiple sensory stimulation methods, such as the Snoezelen method, and aromatherapy. These therapies have shown benefits for dementia-related mood and behaviour disorders in the short term, with few side effects. Since olfactory chemosensory stimulation may be beneficial, it may be proposed in patients with dementia, especially Alzheimer-type dementia, as a complementary or even alternative therapy to existing medical strategies.

  1. Special challenges for public health with climate change and aging populations: Waterborne illness - 20th Annual John K. Friesen Conference - Growing Old in a Changing Climate: Exploring the Interface Between Population Aging and Global Warming (2011)

    OpenAIRE

    Takaro, Tim

    2011-01-01

    This video clip comprises the four presentations of Panel Session 4, “Preparing Aging Populations for Climate Change in British Columbia and Beyond” held at the 20th Annual John K. Friesen Conference, "Growing Old in a Changing Climate: Exploring the Interface Between Population Aging and Global Warming," MAY 25-26, 2011, Vancouver, BC. Dr. Tim Takaro "Special challenges for public health with climate change and aging populations: Waterborne illness" - Climate change is causing public health ...

  2. Longitudinal and cross-sectional changes with age in selected anthropometric and physiological traits in hospitalized adults: an insight from the Polish Longitudinal Study of Aging (PLSA

    Directory of Open Access Journals (Sweden)

    Chmielewski Piotr

    2015-12-01

    Full Text Available Longitudinal studies of aging concerning individuals with comparable lifestyle, diet, health profile, socioeconomic status, and income remain extraordinarily rare. The purposes of our ongoing project are as follows: (i to collect extensive data on biological and medical aspects of aging in the Polish population, (ii to determine factors affecting the rate and course of aging, (iii to understand how aging unfolds as a dynamic and malleable process in ontogeny, and (iv to find novel predictors of longevity. Our investigation followed 142 physically healthy asylum inmates, including 68 males and 74 females, for at least 25 years from the age of 45 years onward. Cross-sectional assessment involved 225 inmates, including 113 males and 112 females. All the patients lived for a very long time under similar and good environmental conditions at the hospital in Cibórz, Lubuskie Province. They maintained virtually the same daily schedule and lifestyle. The rate and direction of changes with age in selected anthropometric and physiological traits were determined using ANOVA, t-test, and regression analysis. There were sex differences in the rate and pattern of age-related changes in certain characteristics such as relative weight, red blood cell count, monocyte count, thymol turbidity value, systolic blood pressure, and body temperature. Body weight, the body mass index (BMI, and total bilirubin level increased with advancing age, while body height decreased with age in both sexes. In conclusion, the aging process was associated with many regressive alterations in biological traits in both sexes but the rate and pattern of these changes depended on biological factors such as age and sex. There were only few characteristics which did not change significantly during the period under study. On the basis of comparison between the pattern of longitudinal changes with aging and the pattern of cross-sectional changes with age in the analyzed traits, we were able

  3. The Corneoscleral Shell of the Eye: an Age-Related Analysis of Structural Biomechanical Properties. Literature review

    Directory of Open Access Journals (Sweden)

    E. N. Iomdina

    2016-01-01

    Full Text Available Structural biomechanical properties of the ocular corneoscleral shell largely determine its anatomic and optical parameters and its supporting and protective function. Therefore, changes related to age restructuring processes may affect the state of the cornea and the sclera, which should be taken into account in diagnosing eye diseases, especially age-related. According to actual literary data, age-related changes of the corneoscleral shell affecting its biomechanical properties involve all connective tissue components of the extracellular matrix: fibrous proteins (collagen and elastin and intermediate substance components (proteoglycans and glycosaminoglycans. Aged patients have a larger diameter of elastic fiber fibrils in the external part of the sclera and a lower density of fibrils in the center as compared to young patients, which is an evidence of elastin damage at the molecular level and fibril degeneration. Age-related changes of proteoglycans are primarilymanifested in hydration loss, which leads to an increase in corneal and sclera density and regional thinning of tissues. Agerelated changes of collagen are less expressed than those of elastin and proteoglycans. Yet, the distance between collagen fibrils in the cornea becomes smaller with age; they are subject to destruction, and small spaces devoid of collagen tend to appear in the posterior stroma. The most pronounced age-related degenerative changes of collagen in the deeper layers of the corneal stroma occur in the limb, which accumulates more cross striated collagen fibrils. Recent years of research have shown that the formation of cross-linked chemical bonds, i.e. intra- and intermolecular cross links of collagen is the most important structural factor. It is this particular process that is responsible for structural stability of the corneal and scleral tissue, which tends to change with age or due to certain eye diseases, such as keratoconus or progressive myopia

  4. Age-Related Changes in Segmental Body Composition by Ethnicity and History of Weight Change across the Adult Lifespan

    Science.gov (United States)

    Tian, Simiao; Morio, Béatrice; Denis, Jean-Baptiste; Mioche, Laurence

    2016-01-01

    This study assessed age-related changes in body composition (specifically in trunk fat and appendicular lean masses), with consideration of body mass index (BMI) at age 20 years (BMI reference age, “BMIref”), ethnicity and lifetime weight change history. A cross-sectional dual-energy X-ray absorptiometry-based dataset was extracted from the U.S. National Health and Nutrition Examination Survey (NHANES) 1999–2004. Only European-American and African-American subjects were used (2705 men, 2527 women). For each gender and ethnicity, 6 analytic cases were considered, based on three BMIref categories (normal, overweight and obese, being 22, 27 and 30 kg/m2, respectively) and two weight contexts (stable weight or weight gain across the lifespan). A nonparametric model was developed to investigate age-related changes in body composition. Then, parametric modelling was developed for assessing BMIref- and ethnicity-specific effects during aging. In the stable weight, both genders’ and ethnicities’ trunk fat (TF) increased gradually; body fat (BF) remained stable until 40 years and increased thereafter; trunk lean (TL) remained stable, but appendicular lean (APL) and body lean (BL) declined from 20 years. In the weight gain context, TF and BF increased at a constant rate, while APL, TL and BL increased until 40–50 years, and then declined slightly. Compared with European-American subjects of both genders, African-American subjects had lower TF and BF masses. Ethnic differences in body composition were quantified and found to remain constant across the lifespan. PMID:27529269

  5. Changes in household size and structure in China.

    Science.gov (United States)

    Jiang, Z; Zeng, Y

    1994-12-01

    Chinese population policies have affected family dynamics as well as population size. The erratic administration of policies in rural and urban areas and among minorities and the Han majority has resulted in big differences in fertility and household size. The political structure allows for rapid changes in policy to be felt immediately. The family planning network has been effective and future fertility decline is expected. The mean age at marriage and divorces are expected to increase during the modernization process in China. Households will be affected under rapid socioeconomic development. Co-residence between parents and married children will become more undesirable, and household size will continue to decline. Co-residence will be affected differently by various factors. Co-residence will decline due to rapid economic development, access to pensions and social security, new housing construction, and relaxation of restriction migration policies. Co-residence will flourish under policies that promote the rural family contract responsibility system of production, that exclude rural farmers from a pension system, and that do not promote the three-generation household as a Chinese cultural tradition. Migration may add to extended families on a temporary basis. The Chinese ethical tradition of caring for the old is still alive. The opposing forces of tradition and change will determine the future structure of households. Children born during the 1970s will have fewer siblings, which will lessen the chances of leaving the parental home. A time may come when below replacement fertility will not allow for co-residence. The speed of transition to nuclear families has not yet been determined. From the 1920s through the 1940s household size was 5.3 members. By 1953 and 1964 household size had declined to 4.3 members. Even up to the 1960s fertility was around 5.68 members; reforms in land allocation began during the 1950s. By 1982 household size increased slightly to 4

  6. Does competitive entry structurally change key marketing metrics?

    NARCIS (Netherlands)

    Kornelis, M.; Dekimpe, de M.G.; Leeflang, P.S.H.

    2008-01-01

    To what extent does competitive entry create a structural change in keymarketingmetrics? New players may just be a temporal nuisance to incumbents, but could also fundamentally change the latter's performance evolution, or induce them to permanently alter their spending levels and/or pricing decisio

  7. Does competitive entry structurally change key marketing metrics?

    NARCIS (Netherlands)

    Kornelis, Marcel; Dekimpe, Marnik G.; Leeflang, Peter S. H.

    2008-01-01

    To what extent does competitive entry create a structural change in key marketing metrics? New players mayjust be a temporal nuisance to incumbents, but could also fundamentally change the latter's performance evolution, or induce them to permanently alter their spending levels and/or pricing decisi

  8. Age-related histomorphologic changes in the canine gastrointestinal tract: A histologic and immunohistologic study

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    AIM: To examine the changes in the histomorphology of the gastric, jejunal and colonic wall of dogs due to physiological aging.METHODS: Full thickness biopsies were taken from the gastrointestinal tracts of 28 dogs of different ages.The thickness of the different layers of the wall was measured and the numbers of proliferating cells as indicated by immunohistochemical detection of Ki67 were counted.RESULTS: In the three excision sites, the thickness of all subepithelial layers increased with rising age. The strongest correlation between age and thickness of the intestinal wall was found in the first 10 years of life and in the jejunum (r = 0.6-0.71 for the deep lamina propria mucosa, the muscularis mucosa, and the circular layer of the tunica muscularis). The number of proliferating cells decreased during aging, with the strongest correlation in the lamina propria mucosa and lamina muscularis mucosa of the jejunum and in the colonic submucosa (r= -0.61 to -0.71). Epithelial proliferation was only weakly correlated to the age.CONCLUSION: The morphology of the deeper layers and the proliferation of mesenchymal cells of the intestinal wall of healthy dogs are correlated with age.Gastrointestinal epithelial proliferation is only weakly age-correlated.

  9. Aging-induced changes in brain regional serotonin receptor binding: Effect of Carnosine.

    Science.gov (United States)

    Banerjee, S; Poddar, M K

    2016-04-01

    Monoamine neurotransmitter, serotonin (5-HT) has its own specific receptors in both pre- and post-synapse. In the present study the role of carnosine on aging-induced changes of [(3)H]-5-HT receptor binding in different brain regions in a rat model was studied. The results showed that during aging (18 and 24 months) the [(3)H]-5-HT receptor binding was reduced in hippocampus, hypothalamus and pons-medulla with a decrease in their both Bmax and KD but in cerebral cortex the [(3)H]-5-HT binding was increased with the increase of its only Bmax. The aging-induced changes in [(3)H]-5-HT receptor binding with carnosine (2.0 μg/kg/day, intrathecally, for 21 consecutive days) attenuated in (a) 24-month-aged rats irrespective of the brain regions with the attenuation of its Bmax except hypothalamus where both Bmax and KD were significantly attenuated, (b) hippocampus and hypothalamus of 18-month-aged rats with the attenuation of its Bmax, and restored toward the [(3)H]-5-HT receptor binding that observed in 4-month-young rats. The decrease in pons-medullary [(3)H]-5-HT binding including its Bmax of 18-month-aged rats was promoted with carnosine without any significant change in its cerebral cortex. The [(3)H]-5-HT receptor binding with the same dosages of carnosine in 4-month-young rats (a) increased in the cerebral cortex and hippocampus with the increase in their only Bmax whereas (b) decreased in hypothalamus and pons-medulla with a decrease in their both Bmax and KD. These results suggest that carnosine treatment may (a) play a preventive role in aging-induced brain region-specific changes in serotonergic activity (b) not be worthy in 4-month-young rats in relation to the brain regional serotonergic activity. PMID:26808776

  10. Aging and perceived event structure as a function of modality.

    Science.gov (United States)

    Magliano, Joseph; Kopp, Kristopher; McNerney, M Windy; Radvansky, Gabriel A; Zacks, Jeffrey M

    2012-01-01

    The majority of research on situation model processing in older adults has focused on narrative texts. Much of this research has shown that many important aspects of constructing a situation model for a text are preserved and may even improve with age. However, narratives need not be text-based, and little is known as to whether these findings generalize to visually-based narratives. The present study assessed the impact of story modality on event segmentation, which is a basic component of event comprehension. Older and younger adults viewed picture stories or read text versions of them and segmented them into events. There was comparable alignment between the segmentation judgments and a theoretically guided analysis of shifts in situational features across modalities for both populations. These results suggest that situation models provide older adults with a stable basis for event comprehension across different modalities of expereinces.

  11. 3-Deoxyglucosone: a potential glycating agent accountable for structural alteration in H3 histone protein through generation of different AGEs.

    Directory of Open Access Journals (Sweden)

    Jalaluddin M Ashraf

    Full Text Available Advanced glycation end-products (AGEs are heterogeneous group of compounds, known to be implicated in diabetic complications. One of the consequences of the Maillard reaction is attributed to the production of reactive intermediate products such as α-oxoaldehydes. 3-deoxyglucosone (3-DG, an α-oxoaldehyde has been found to be involved in accelerating vascular damage during diabetes. In the present study, calf thymus histone H3 was treated with 3-deoxyglucosone to investigate the generation of AGEs (Nε-carboxymethyllysine, pentosidine, by examining the degree of side chain modifications and formation of different intermediates and employing various physicochemical techniques. The results clearly indicate the formation of AGEs and structural changes upon glycation of H3 by 3-deoxyglucosone, which may hamper the normal functioning of H3 histone, that may compromise the veracity of chromatin structures and function in secondary complications of diabetes.

  12. Structural Changes of Polyethylene Terephthalate Fibers Grafted by Acrylamide

    Institute of Scientific and Technical Information of China (English)

    施琴芬; 戴礼兴

    2003-01-01

    A group of grafted PET fibers with different graft yield are formed by grafiing acrylamide onto the PET main chains. The structure of grafted fibers are studied by scanning electronic microscope ( SEM ), infra-red spectrophotometer (IR), and differential scanning calorimetry( DSC ). At the same time, the moisture regain, dyeability, strength, and elongation at break of the samples are measured and their relations with structural changes are discussed. Compared with ungrafted fiber, shape of the fiber cross-section, IR characteristic absorption peaks, and melting behavior of the grafted fibers have been changed, causing the fiber dyeability and moisture regain to be increased, and mechanical properties to be changed.

  13. Continuous Age-Structured Model for Bovine Tuberculosis in African buffalo

    Science.gov (United States)

    Anguelov, R.; Kojouharov, H.

    2009-10-01

    The paper deals with a model of the spread of bovine tuberculosis in the buffalo population in the Kruger National Park in South Africa. The model uses continuous age structure and it is formulated in terms of partial differential equations using eight epidemiological classes (compartments). More precisely, the age density for each class at time t satisfies a one way wave equation, where the age is the space variable. The continuous age model discussed here is derived from a 2006 age groups model by P. C. Cross and W. M. Getz.

  14. Age-related changes in intrinsic function of the superior temporal sulcus in autism spectrum disorders.

    Science.gov (United States)

    Alaerts, Kaat; Nayar, Kritika; Kelly, Clare; Raithel, Jessica; Milham, Michael P; Di Martino, Adriana

    2015-10-01

    Currently, the developmental trajectories of neural circuits implicated in autism spectrum disorders (ASD) are largely unknown. Here, we specifically focused on age-related changes in the functional circuitry of the posterior superior temporal sulcus (pSTS), a key hub underlying social-cognitive processes known to be impaired in ASD. Using a cross-sectional approach, we analysed resting-state functional magnetic resonance imaging (fMRI) data collected from children, adolescents and adults available through the autism brain imaging data exchange repository [n = 106 with ASD and n = 109 typical controls (TC), ages 7-30 years]. The observed age-related changes of pSTS intrinsic functional connectivity (iFC) suggest that no single developmental pattern characterizes ASD. Instead, pSTS circuitry displayed a complex developmental picture, with some functional circuits showing patterns consistent with atypical development in ASD relative to TC (pSTS-iFC with fusiform gyrus and angular gyrus) and others showing delayed maturation (pSTS-iFC with regions of the action perception network). Distinct developmental trajectories in different functional circuits in ASD likely reflect differential age-related changes in the socio-cognitive processes they underlie. Increasing insight on these mechanisms is a critical step in the development of age-specific interventions in ASD. PMID:25809403

  15. Age-related changes in retinoic, docosahexaenoic and arachidonic acid modulation in nuclear lipid metabolism.

    Science.gov (United States)

    Gaveglio, Virginia L; Pascual, Ana C; Giusto, Norma M; Pasquaré, Susana J

    2016-08-15

    The aim of this work was to study how age-related changes could modify several enzymatic activities that regulate lipid mediator levels in nuclei from rat cerebellum and how these changes are modulated by all-trans retinoic acid (RA), docosahexaenoic acid (DHA) and arachidonic acid (AA). The higher phosphatidate phosphohydrolase activity and lower diacylglycerol lipase (DAGL) activity observed in aged animals compared with adults could augment diacylglycerol (DAG) availability in the former. Additionally, monoacylglycerol (MAG) availability could be high due to an increase in lysophosphatidate phosphohydrolase (LPAPase) activity and a decrease in monocylglycerol lipase activity. Interestingly, RA, DHA and AA were observed to modulate these enzymatic activities and this modulation was found to change in aged rats. In adult nuclei, whereas RA led to high DAG and MAG production through inhibition of their hydrolytic enzymes, DHA and AA promoted high MAG production by LPAPase and DAGL stimulation. In contrast, in aged nuclei RA caused high MAG generation whereas DHA and AA diminished it through LPAPase activity modulation. These results demonstrate that aging promotes a different nuclear lipid metabolism as well as a different type of non-genomic regulation by RA, DHA and AA, which could be involved in nuclear signaling events. PMID:27355428

  16. Lifespan Changes in the Countermanding Performance of Young and Middle Aged Adult Rats.

    Science.gov (United States)

    Beuk, Jonathan; Beninger, Richard J; Paré, Martin

    2016-01-01

    Inhibitory control can be investigated with the countermanding task, which requires subjects to make a response to a go signal and cancel that response when a stop signal is presented occasionally. Adult humans performing the countermanding task typically exhibit impaired response time (RT), stop signal response time (SSRT) and response accuracy as they get older, but little change in post-error slowing. Rodent models of the countermanding paradigm have been developed recently, yet none have directly examined age-related changes in performance throughout the lifespan. Male Wistar rats (N = 16) were trained to respond to a visual stimulus (go signal) by pressing a lever directly below an illuminated light for food reward, but to countermand the lever press subsequent to a tone (stop signal) that was presented occasionally (25% of trials) at a variable delay. Subjects were tested in 1 h sessions at approximately 7 and 12 months of age with intermittent training in between. Rats demonstrated longer go trial RT, a higher proportion of go trial errors and performed less total trials at 12, compared to 7 months of age. Consistent SSRT and post-error slowing were observed for rats at both ages. These results suggest that the countermanding performance of rats does vary throughout the lifespan, in a manner similar to humans, suggesting that rodents may provide a suitable model for behavioral impairment related to normal aging. These findings also highlight the importance of indicating the age at which rodents are tested in countermanding investigations. PMID:27555818

  17. Age-related changes to the neural correlates of working memory which emerge after midlife

    Directory of Open Access Journals (Sweden)

    Helen N Macpherson

    2014-04-01

    Full Text Available Previous research has indicated that the neural processes which underlie working memory change with age. Both age-related increases and decreases to cortical activity have been reported. This study investigated which stages of working memory are most vulnerable to age-related changes after midlife. To do this we examined age-differences in the 13Hz steady state visually evoked potential (SSVEP associated with a spatial working memory delayed response task. Participants were 130 healthy adults separated into a midlife (40 to 60 years and an older group (61 to 82 years. Relative to the midlife group, older adults demonstrated greater bilateral frontal activity during encoding and this pattern of activity was related to better working memory performance. In contrast, evidence of age-related under activation was identified over left frontal regions during retrieval. Findings from this study suggest that after midlife, under-activation of frontal regions during retrieval contributes to age-related decline in working memory performance.

  18. Age-related changes to the neural correlates of working memory which emerge after midlife

    Science.gov (United States)

    Macpherson, Helen N.; White, David J.; Ellis, Kathryn A.; Stough, Con; Camfield, David; Silberstein, Richard; Pipingas, Andrew

    2014-01-01

    Previous research has indicated that the neural processes which underlie working memory change with age. Both age-related increases and decreases to cortical activity have been reported. This study investigated which stages of working memory are most vulnerable to age-related changes after midlife. To do this we examined age-differences in the 13 Hz steady state visually evoked potential (SSVEP) associated with a spatial working memory delayed response task. Participants were 130 healthy adults separated into a midlife (40–60 years) and an older group (61–82 years). Relative to the midlife group, older adults demonstrated greater bilateral frontal activity during encoding and this pattern of activity was related to better working memory performance. In contrast, evidence of age-related under activation was identified over left frontal regions during retrieval. Findings from this study suggest that after midlife, under-activation of frontal regions during retrieval contributes to age-related decline in working memory performance. PMID:24795625

  19. Lifespan Changes in the Countermanding Performance of Young and Middle Aged Adult Rats

    Science.gov (United States)

    Beuk, Jonathan; Beninger, Richard J.; Paré, Martin

    2016-01-01

    Inhibitory control can be investigated with the countermanding task, which requires subjects to make a response to a go signal and cancel that response when a stop signal is presented occasionally. Adult humans performing the countermanding task typically exhibit impaired response time (RT), stop signal response time (SSRT) and response accuracy as they get older, but little change in post-error slowing. Rodent models of the countermanding paradigm have been developed recently, yet none have directly examined age-related changes in performance throughout the lifespan. Male Wistar rats (N = 16) were trained to respond to a visual stimulus (go signal) by pressing a lever directly below an illuminated light for food reward, but to countermand the lever press subsequent to a tone (stop signal) that was presented occasionally (25% of trials) at a variable delay. Subjects were tested in 1 h sessions at approximately 7 and 12 months of age with intermittent training in between. Rats demonstrated longer go trial RT, a higher proportion of go trial errors and performed less total trials at 12, compared to 7 months of age. Consistent SSRT and post-error slowing were observed for rats at both ages. These results suggest that the countermanding performance of rats does vary throughout the lifespan, in a manner similar to humans, suggesting that rodents may provide a suitable model for behavioral impairment related to normal aging. These findings also highlight the importance of indicating the age at which rodents are tested in countermanding investigations. PMID:27555818

  20. Age-related changes in postural control to the demands of a precision task.

    Science.gov (United States)

    Yeh, Ting-Ting; Cinelli, Michael E; Lyons, James L; Lee, Timothy D

    2015-12-01

    Optimal sensorimotor integration is needed to maintain the precision of a visuomotor postural task. Furthermore, cognitive resources have been suggested to be involved in maintaining balance, especially in older adults. This study investigated how older and younger adults differed in employing sensorimotor strategies in a dual-task situation. Older (age 65-84 years) and younger adults (age 19-30 years) performed a visually-based, postural tracking task in different body orientations (from 0° to 45°), which necessitated slightly different task goals. On some trials, participants performed a concurrent silent arithmetic task with the visuomotor tracking task. The results demonstrated that sensorimotor control declined with age. Older adults showed greater medial-lateral center of pressure variability compared to younger adults in the precision task. Younger adults displayed a trend to decrease anterior-posterior variability, but older adults exhibited an opposite trend when the body orientation changed from 0° to 45°. The addition of a dual-task situation decreased overall postural variability in both age groups. Age-related changes in postural control may degrade the flexible coordination of the sensory feedback and motor execution. This study suggested that medial-lateral stability may be more sensitive to this age-related decline and may be closely associated with postural instability and falls.

  1. Light-induced structural changes in a monomeric bacteriophytochrome

    Science.gov (United States)

    Takala, Heikki; Niebling, Stephan; Berntsson, Oskar; Björling, Alexander; Lehtivuori, Heli; Häkkänen, Heikki; Panman, Matthijs; Gustavsson, Emil; Hoernke, Maria; Newby, Gemma; Zontone, Federico; Wulff, Michael; Menzel, Andreas; Ihalainen, Janne A.; Westenhoff, Sebastian

    2016-01-01

    Phytochromes sense red light in plants and various microorganism. Light absorption causes structural changes within the protein, which alter its biochemical activity. Bacterial phytochromes are dimeric proteins, but the functional relevance of this arrangement remains unclear. Here, we use time-resolved X-ray scattering to reveal the solution structural change of a monomeric variant of the photosensory core module of the phytochrome from Deinococcus radiodurans. The data reveal two motions, a bend and a twist of the PHY domain with respect to the chromophore-binding domains. Infrared spectroscopy shows the refolding of the PHY tongue. We conclude that a monomer of the phytochrome photosensory core is sufficient to perform the light-induced structural changes. This implies that allosteric cooperation with the other monomer is not needed for structural activation. The dimeric arrangement may instead be intrinsic to the biochemical output domains of bacterial phytochromes. PMID:27679804

  2. The development of pathogen resistance in Daphnia magna: implications for disease spread in age-structured populations.

    Science.gov (United States)

    Garbutt, Jennie S; O'Donoghue, Anna J P; McTaggart, Seanna J; Wilson, Philip J; Little, Tom J

    2014-11-01

    Immunity in vertebrates is well established to develop with time, but the ontogeny of defence in invertebrates is markedly less studied. Yet, age-specific capacity for defence against pathogens, coupled with age structure in populations, has widespread implications for disease spread. Thus, we sought to determine the susceptibility of hosts of different ages in an experimental invertebrate host-pathogen system. In a series of experiments, we show that the ability of Daphnia magna to resist its natural bacterial pathogen Pasteuria ramosa changes with host age. Clonal differences make it difficult to draw general conclusions, but the majority of observations indicate that resistance increases early in the life of D. magna, consistent with the idea that the defence system develops with time. Immediately following this, at about the time when a daphnid would be most heavily investing in reproduction, resistance tends to decline. Because many ecological factors influence the age structure of Daphnia populations, our results highlight a broad mechanism by which ecological context can affect disease epidemiology. We also show that a previously observed protective effect of restricted maternal food persists throughout the entire juvenile period, and that the protective effect of prior treatment with a small dose of the pathogen ('priming') persists for 7 days, observations that reinforce the idea that immunity in D. magna can change over time. Together, our experiments lead us to conclude that invertebrate defence capabilities have an ontogeny that merits consideration with respect to both their immune systems and the epidemic spread of infection. PMID:25214486

  3. Direct measurement of riverine particulate organic carbon age structure

    Science.gov (United States)

    Rosenheim, Brad E.; Galy, Valier

    2012-10-01

    Carbon cycling studies focusing on transport and transformation of terrigenous carbon sources toward marine sedimentary sinks necessitate separation of particulate organic carbon (OC) derived from many different sources and integrated by river systems. Much progress has been made on isolating and characterizing young biologically-formed OC that is still chemically intact, however quantification and characterization of old, refractory rock-bound OC has remained troublesome. Quantification of both endmembers of riverine OC is important to constrain exchanges linking biologic and geologic carbon cycles and regulating atmospheric CO2 and O2. Here, we constrain petrogenic OC proportions in suspended sediment from the headwaters of the Ganges River in Nepal through direct measurement using ramped pyrolysis radiocarbon analysis. The unique results apportion the biospheric and petrogenic fractions of bulk particulate OC and characterize biospheric OC residence time. Compared to the same treatment of POC from the lower Mississippi-Atchafalaya River system, contrast in age spectra of the Ganges tributary samples illustrates the difference between small mountainous river systems and large integrative ones in terms of the global carbon cycle.

  4. Longitudinal change in language production: effects of aging and dementia on grammatical complexity and propositional content.

    Science.gov (United States)

    Kemper, S; Marquis, J; Thompson, M

    2001-12-01

    Mixed modeling was used to examine longitudinal changes in linguistic ability in healthy older adults and older adults with dementia. Language samples, vocabulary scores, and digit span scores were collected annually from healthy older adults and semiannually from older adults with dementia. The language samples were scored for grammatical complexity and propositional content. For the healthy group, age-related declines in grammatical complexity and propositional content were observed. The declines were most rapid in the mid 70s. For the group with dementia, grammatical complexity and propositional content also declined over time, regardless of age. Rates of decline were uniform across individuals. These analyses reveal how both grammatical complexity and propositional content are related to late-life changes in cognition in healthy older adults aswell as those with dementia. Alzheimer's disease accelerates this decline, regardless of age.

  5. Deep sleep and parietal cortex gene expression changes are related to cognitive deficits with age.

    Directory of Open Access Journals (Sweden)

    Heather M Buechel

    Full Text Available BACKGROUND: Age-related cognitive deficits negatively affect quality of life and can presage serious neurodegenerative disorders. Despite sleep disruption's well-recognized negative influence on cognition, and its prevalence with age, surprisingly few studies have tested sleep's relationship to cognitive aging. METHODOLOGY: We measured sleep stages in young adult and aged F344 rats during inactive (enhanced sleep and active (enhanced wake periods. Animals were behaviorally characterized on the Morris water maze and gene expression profiles of their parietal cortices were taken. PRINCIPAL FINDINGS: Water maze performance was impaired, and inactive period deep sleep was decreased with age. However, increased deep sleep during the active period was most strongly correlated to maze performance. Transcriptional profiles were strongly associated with behavior and age, and were validated against prior studies. Bioinformatic analysis revealed increased translation and decreased myelin/neuronal pathways. CONCLUSIONS: The F344 rat appears to serve as a reasonable model for some common sleep architecture and cognitive changes seen with age in humans, including the cognitively disrupting influence of active period deep sleep. Microarray analysis suggests that the processes engaged by this sleep are consistent with its function. Thus, active period deep sleep appears temporally misaligned but mechanistically intact, leading to the following: first, aged brain tissue appears capable of generating the slow waves necessary for deep sleep, albeit at a weaker intensity than in young. Second, this activity, presented during the active period, seems disruptive rather than beneficial to cognition. Third, this active period deep sleep may be a cognitively pathologic attempt to recover age-related loss of inactive period deep sleep. Finally, therapeutic strategies aimed at reducing active period deep sleep (e.g., by promoting active period wakefulness and/or inactive

  6. The quantum age of it why everything you know about it is about to change

    CERN Document Server

    Araujo, Charles

    2012-01-01

    In The Quantum Age of IT, Charles Araujo examines what has led us to this point and what it means to the future of IT organizations. With a broad perspective on the fundamental changes affecting the industry, he offers practical guidance that every IT professional needs to compete in this new era of IT.

  7. Sexism and eating disorders: gender differences, changes with age, and relations between both constructs

    OpenAIRE

    Garaigordobil, Maite; Maganto, Carmen

    2013-01-01

    Concern about the prevalence of sexism and eating disorders (EDs) underlies this study, which had two goals: 1) To analyze gender differences and changes with age in sexism and in eating disorders (EDs) (DT-drive for thinness, BN-bulimia, BD-body dissatis

  8. Segmentation of age-related white matter changes in a clinical multi-center study

    DEFF Research Database (Denmark)

    Dyrby, Tim B.; Rostrup, E.; Baare, W.F.C.;

    2008-01-01

    Age-related white matter changes (WMC) are thought to be a marker of vascular pathology, and have been associated with motor and cognitive deficits. In the present study, an optimized artificial neural network was used as an automatic segmentation method to produce probabilistic maps of WMC...

  9. Condylar Changes and Its Association with Age, TMD, and Dentition Status: A Cross-Sectional Study

    Directory of Open Access Journals (Sweden)

    Anuna Laila Mathew

    2011-01-01

    Full Text Available The present study was undertaken to evaluate the prevalence of radiographic changes in the condylar morphology and its association with age, clinical signs and symptoms of temporomandibular dysfunction and dentition status and also to evaluate the intra examiner and inter examiner reliability in assessing condylar changes using panoramic radiographs. A total of 75 subjects were recruited for the study. They were divided into 3 age groups. 20–40 yrs (Group A, 41–60 yrs (Group B and 61 yrs and above (Group C. In each age group 25 subjects were evaluated both clinically and radiographically. The prevalence of radiographic changes in condylar morphology and symptoms of temporomandibular dysfunction was 81.3% and 18.6%, respectively. Radiographic abnormalities in the mandibular condylar morphology increased with age. They were seen more frequently in patients with clinical signs and symptoms of temporomandibular dysfunction and in patients with loss of teeth. Intra examiner and inter examiner reliability was high indicating a good reliability in assessing the condylar changes using panoramic radiograph.

  10. Age-related changes in body composition in laboratory rats: Strain and gender comparisons

    Science.gov (United States)

    Long Evans (LE), Sprague Dawley (SD), Fischer 344 (F344), and Brown Norway (BN) rats are all commonly used as laboratory research subjects. These strains have been studied under many conditions, but few studies have measured changes in body composition as the animals age. Underst...

  11. Age-related changes in human vestibulo-ocular and optokinetic reflexes: Pseudorandom rotation tests

    Science.gov (United States)

    Peterka, R. J.; Black, F. O.; Schoenhoff, M. B.

    1989-01-01

    The dynamic response properties of horizontal vestibulo-ocular reflex (VOR) and optokinetic reflex (OKR) were characterized in 216 human subjects ranging in age from 7 to 81 years. The object of this cross-sectional study was to determine the effects of aging on VOR and OKR reflex dynamics, and to identify the distributions of parameters which describe VOR and OKR responses to pseudorandom stimuli in a putatively normal population. In general, VOR and OKR response parameters changed in a manner consistent with declining function with increasing age. For the VOR this was reflected in declining response amplitudes, although the magnitude of the decline was small relative to the variability of the data. For the OKR the lag time of the response, probably associated with the time required for visual information processing, increased linearly with age at a rate of about 1 ms per year.

  12. Age-related changes of muscle and plasma amino acids in healthy children.

    Science.gov (United States)

    Hammarqvist, Folke; Angsten, Gertrud; Meurling, Staffan; Andersson, Kerstin; Wernerman, Jan

    2010-07-01

    The aim of the study was to explore if changes in muscle and plasma amino acid concentrations developed during growth and differed from levels seen in adults. The gradient and concentrations of free amino acids in muscle and plasma were investigated in relation to age in metabolic healthy children. Plasma and specimens from the abdominal muscle were obtained during elective surgery. The children were grouped into three groups (group 1: amino acids analysed increased with age, namely taurine, aspartate, threonine, alanine, valine, isoleucine, leucine, histidine, as well as the total sums of branched chain amino acids (BCAA), basic amino acids (BAA) and total sum of amino acids (P amino acids correlated with age (P < 0.05). These results indicate that there is an age dependency of the amino acid pattern in skeletal muscle and plasma during growth.

  13. Age-specific forced polymorphism: implications of ontogenetic changes in morphology for male mating tactics.

    Science.gov (United States)

    Irschick, Duncan J; Lailvaux, Simon P

    2006-01-01

    Age-specific forced polymorphism is the presence of two or more distinct phenotypes (here we consider only males) that occur in separate sexually mature age groups (e.g., horns in older males but not younger males). The life-stage morph maturation hypothesis posits that all younger males that possess a particular structure can transform into older males with a different structure, most likely via the influence of hormones. The life-stage morph selection hypothesis posits that polymorphism is due to intense selection resulting in a highly nonrandom sample of younger males surviving to become older males, thus leading to different mean phenotypes in different age groups. We conducted an extensive review of literature from the past 20 years (1983-2003) for cases of age-specific forced polymorphism. Overall, we found only a few cases that fit our criteria of age-specific forced polymorphism, and we argue that most (e.g., orangutans, elephant seals) have likely arisen via the life-stage morph maturation mechanism, but we also present several examples (e.g., green anole lizards) that appear to be candidates for life-stage morph selection. However, none of the reviewed studies provided enough information (e.g., age of morphs, growth patterns of the morphological structure) to definitively invoke either of the two mechanisms. We suggest that age-specific forced polymorphism is more common than reflected in this review and that future studies should gather demographic and laboratory data that will directly compare the life-stage morph maturation and life-stage morph selection hypotheses. PMID:16380929

  14. Age and SPARC Change the Extracellular Matrix Composition of the Left Ventricle

    Directory of Open Access Journals (Sweden)

    Lisandra E. de Castro Brás

    2014-01-01

    Full Text Available Secreted protein acidic and rich in cysteine (SPARC, a collagen-binding matricellular protein, has been implicated in procollagen processing and deposition. The aim of this study was to investigate age- and SPARC-dependent changes in protein composition of the cardiac extracellular matrix (ECM. We studied 6 groups of mice (n=4/group: young (4-5 months old, middle-aged (11-12 m.o., and old (18–29 m.o. C57BL/6J wild type (WT and SPARC null. The left ventricle (LV was decellularized to enrich for ECM proteins. Protein extracts were separated by SDS-PAGE, digested in-gel, and analyzed by HPLC-ESI-MS/MS. Relative quantification was performed by spectral counting, and changes in specific proteins were validated by immunoblotting. We identified 321 proteins, of which 44 proteins were extracellular proteins. Of these proteins, collagen III levels were lower in the old null mice compared to WT, suggestive of a role for SPARC in collagen deposition. Additionally, fibrillin showed a significant increase in the null middle-aged group, suggestive of increased microfibril deposition in the absence of SPARC. Collagen VI increased with age in both genotypes (>3-fold, while collagen IV showed increased age-associated levels only in the WT animals (4-fold, P<0.05. These changes may explain the previously reported age-associated increases in LV stiffness. In summary, our data suggest SPARC is a possible therapeutic target for aging induced LV dysfunction.

  15. Quantitative and qualitative changes in human MeissnerAND#8217;s corpuscle at different ages: a light microscopic analysis

    Directory of Open Access Journals (Sweden)

    Gh Mohd Bhat

    2014-06-01

    Full Text Available Background: Meissner and #8217;s corpuscle is the most complex sensory receptors of the skin; providing information about rapidly fluctuating mechanical forces acting on the hairless skin. Aim of current study was to study density and structural changes in human Meissner and #8217;s corpuscles at different ages Methods: Samples were obtained from finger tips of fifteen persons and divided into three groups according to age: group A <15years; group B: 16-45 years and group C: 46-72 years. 5 and micro;m thick sections were prepared, impregnated with silver and observed under compound light microscope. Density of Meissner and #8217;s corpuscles (Mcs was studied by calculating Meissner and #8217;s Index (MI. Results: In group A, the MI was 0.86-0.90, which increased to 0.96 in group B and dropped in group C to 0.4 (in the seventh decade. The analysis of variance showed significant difference (P = 0.019 in MIs of the three age groups. The size of the Mcs was largest in group B, followed by group C and smallest in group A. The analysis of variance showed that there was highly significant difference (P = 0.003 between the size of Mcs in all the three age groups. It was observed that morphology of Mcs alter with age. In children these consisted of rudimentary coil of nerve fibers around collection of cells. In adults the intra-corpuscular nerve fibers were compressed into a tight spiral and modifications of nerve fibers, like end bulbs, varicosities and networks, were well developed. In old age Mcs were attenuated consisting of tangled mass of nerve fibers. Conclusion: It can be concluded that in adults the Mcs are greater in number, larger in size and complicated in structure, compared to young and old people. [Int J Res Med Sci 2014; 2(3.000: 852-856

  16. Age-related changes of serum mitochondrial uncoupling 1, rumen and rectal temperature in goats.

    Science.gov (United States)

    Arfuso, Francesca; Rizzo, Maria; Giannetto, Claudia; Giudice, Elisabetta; Fazio, Francesco; Piccione, Giuseppe

    2016-07-01

    Thermoregulatory processes are induced not only by exposure to cold or heat but also by a variety of physiological situations including age, fasting and food intake that result in changes in body temperature. The aim of the present study was to evaluate the differences in serum mitochondrial uncoupling protein 1 (UCP1), rumen temperature (TRUMEN) and rectal temperature (TRECTAL) values between adult and kids goats. Ten adult male Maltese goats aged 3-5 years old (Group A) and 30 male kids, raised for meat, were enrolled in this study. The kids were equally divided into 3 groups according to their age: Group B included kids aged 3 months, Group C included kids aged 4 months and Group D included kids aged 5 months. Blood samples and measurements of TRUMEN and TRECTAL were obtained from each animal. One-way repeated measures analysis of variance (ANOVA) was applied to evaluate the effect of age on the studied parameters. Statistically significant higher serum UCP1 levels (Ptemperature suggesting that further details about the thermogenic capacity and the function of UCP1 in kids and adult goats are worth exploring.

  17. Color Doppler Imaging of Ophthalmic Arteries : Age Related Changes in the Normal Subjects

    International Nuclear Information System (INIS)

    Color Doppler imaging (CDI) with Doppler spectral analysis was done to evaluate the age related changes of the ophthalmic arteries in 60 normotensive subjects (Age : 19∼64y, mean =38.3y, M : F = 1 : 1). A 7 MHz linear transducer for small parts (Acuson L7384) was used. The ophthalmic artery about 1∼1.5 cm behind the optic nerve head was depicted by the CDI. The maximum peak velocity (S1), the second peak velocity (S2), the maximum peak diastolic velocity (D1) and the end diastolic velocity (D*2) were recorded. Additionally, the piteously index(PI), the resistive index (RI), the ratio of S1 to S2 (S1 / S2) and the ratio of S1 to D1 (S1 / D1) were calculated. Correlation between the age and the above indices (ratio) was estimated. PI, RI, S1 / S2 and S1 / D1 declined progressively as a function of advancing age. The S1 / S2 showed the strongest inverse correlation with age (r = -0.667). The meaning of the S2's in old age is not clear. It could be related to the decreased compliance of the aged ophthalmic arteries

  18. Effect of yogic practices on age related changes in oxygen metabolism and antioxidant-redox status

    Directory of Open Access Journals (Sweden)

    Rameswar Pal

    2013-08-01

    Full Text Available Objective: The aim of the study was to evaluate the effect of yogic practice on age related changes in antioxidants and redox status, resting metabolism and energy expenditure. Methods: The study was conducted on 60 healthy male volunteers of three age groups viz 20-29 years, 30-39 years and 40-50 years. In addition to their routine activities, volunteers practiced yogasana, pranayama and meditation for a period of 3 months. Blood samples were collected in fasting condition before and after 3 months of yogic practice for the estimation of biochemical parameters. Results: Oxygen consumption and energy expenditure were decreased with the advancement of age and after yogic practice. Respiratory quotient was increased with the age and decreased after yogic practice. Advancement of age showed progressive shifting of redox status towards the oxidized state, which restored by yogic practice. Lowered levels of reduced glutathione, the ratio of reduced to oxidized glutathione, total antioxidant status, vitamin C and vitamin E as well as the activity of enzymes such as superoxide dismutase, catalase, glutathione reductase and glutathione S-transferase were associated with aging. The regular yogic practice helps to improve in these above mentioned parameters. Hydroperoxides, protein carbonyl, malondialdehyde and glutathione peroxidase levels were found to be higher due to progression of age. These have been decreased after yogic practice. Conclusion: Regular yogic practices have the ability to revert back with the changes in antioxidant and redox status due to advancement of age. [J Exp Integr Med 2013; 3(4.000: 305-312

  19. Reference ranges and age-related changes of peripheral blood lymphocyte subsets in Chinese healthy adults

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This study was performed to build region-specific reference ranges of peripheral blood lymphocyte subsets for Chinese healthy adults from the young to the elderly and analyze the trends of changes in lymphocyte subsets for evaluating the impact of age on the values.151 healthy adults aged 19-86 were recruited based on the SENIEUR protocol.Three sets of reference ranges were finally built applicable for the healthy young(19-44 years),middle-aged(45-64 years) and elder adults(≥65).Comparisons in parameters among the three cohorts showed that a statistically significant increase in CD16CD56+ NK cell was observed between the middle-aged and elder cohorts,whereas for the majority of the parameters,a significant decline was observed between the young and the middle-aged cohorts.Further results showed that inverse correlations were observed between the age and CD19+ B,CD3+ T,CD3+CD4+ T,CD4+CD45RA+CD62L+ nave T cell and CD4+CD28+/CD4+,while the positive one was identified between the age and the NK cell.These significant changes of the most of immune parameters provided evidence for immunosenescence.Notably,T cell activation markers of CD8+CD38+ and CD8+HLA-DR+ showed reverse trends of association with age,which provides a clue for further researches on the mechanisms underlying the paradoxical clinical presentation of the elder patients.

  20. Age-related changes in conventional road versus off-road triathlon performance.

    Science.gov (United States)

    Lepers, Romuald; Stapley, Paul J

    2011-08-01

    The aims of this study were: (i) to analyze age-related declines in swimming, cycling, and running performances for road-based and off-road triathlons, and (ii) to compare age-related changes in these three disciplines between road-based and off-road triathlons. Swimming, cycling, running and total time performances of the top five males between 20 and 70 years of age (in 5-year intervals) were analyzed for short distance road-based (1.5 km swim, 40 km cycle, and 10 km run) and off-road (1.5 km swim, 30 km mountain bike, and 11 km trail run) triathlons at the 2009 World Championships. Independently of age, there was a lesser age-related decline in cycling performance (P road-based triathlon. In contrast, age-related decline did not differ between the three locomotion modes for off-road triathlon. With advancing age, the performance decline was less pronounced (P road-based than for off-road triathlon in swimming (≥65 years), cycling (≥50 years), running (≥60 years), and total event (≥55 years) times, respectively. These results suggest that the rate of the decline in performance for off-road triathlon is greater than for road-based triathlon, indicating that the type of discipline (road vs. mountain bike cycling and road vs. trail running) exerts an important influence on the magnitude of the age-associated changes in triathlon performance.

  1. Alterations in the expression of atrial calpains in electrical and structural remodeling during aging and atrial fibrillation.

    Science.gov (United States)

    Xu, Guo-Jun; Gan, Tian-Yi; Tang, Bao-Peng; Chen, Zu-Heng; Mahemuti, Ailiman; Jiang, Tao; Song, Jian-Guo; Guo, Xia; Li, Yao-Dong; Zhou, Xian-Hui; Zhang, Yu; Li, Jin-Xin

    2013-11-01

    The aim of this study was to investigate the correlation between the change in the expression of atrial calpains and electrical, molecular and structural remodeling during aging and atrial fibrillation (AF). Adult and aged canines in sinus rhythm (SR) and with persistent AF (induced by rapid atrial pacing) were investigated. A whole-cell patch clamp was used to measure the L-type Ca2+ current (ICa-L) in cells in the left atrium. The mRNA and protein expression of the L-type calcium channel alc subunit (LVDCCa1c) and calpains were measured by quantitative (q)PCR and western blot analysis. Histopathological and ultrastructural changes were analyzed via light and electron microscopy. The quantity of apoptotic myocytes was determined by a terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling (TUNEL) assay. In SR groups, atrial cells of the aged canines exhibited a longer action potential (AP) duration to 90% repolarization (APD90), lower AP plateau potential and peak ICa-L current densities (Pcontrol group, the mRNA and protein expression levels of LVDCCa1c were decreased in the aged groups; however, the mRNA and protein expression of calpain 1 was increased in the adult and the aged groups with AF (Patrial tissue exhibited abnormal histopathological and ultrastructural changes, such as accelerated fibrosis and apoptosis with aging and in AF. Age-related alterations in atrial tissues were attributed to the increased expression of calpain 1. The general pathophysiological alterations in normal aged atria may therefore produce a substrate that is conducive to AF. PMID:24043247

  2. Structural and functional rejuvenation of the aged brain by an approved anti-asthmatic drug

    OpenAIRE

    Marschallinger, J.; I. Schäffner; B. Klein(Ghent University, Ghent, Belgium); R. Gelfert; F.J. Rivera; S. Illes; L. Grassner; Janssen, M.; P. Rotheneichner; C. Schmuckermair; R. Coras; M. Boccazzi; M. Chishty; F.B. Lagler; M. Renic

    2015-01-01

    As human life expectancy has improved rapidly in industrialized societies, age-related cognitive impairment presents an increasing challenge. Targeting histopathological processes that correlate with age-related cognitive declines, such as neuroinflammation, low levels of neurogenesis, disrupted blood–brain barrier and altered neuronal activity, might lead to structural and functional rejuvenation of the aged brain. Here we show that a 6-week treatment of young (4 months) and old (20 months) ...

  3. Electrocardiographic Changes Improve Risk Prediction in Asymptomatic Persons Age 65 Years or Above Without Cardiovascular Disease

    DEFF Research Database (Denmark)

    Jørgensen, Peter Godsk; Jensen, Jan S; Marott, Jacob L;

    2014-01-01

    BACKGROUND: Risk prediction in elderly patients is increasingly relevant due to longer life expectancy. OBJECTIVES: This study sought to examine whether electrocardiographic (ECG) changes provide prognostic information incremental to current risk models and to the conventional risk factors. METHODS......: In all, 6,991 participants from the Copenhagen Heart Study attending an examination at age ≥65 years were included. ECG changes were defined as Q waves, ST-segment depression, T-wave changes, ventricular conduction defects, and left ventricular hypertrophy based on the Minnesota code. The primary...

  4. Age-related changes in brain hemodynamics; A calibrated MRI study

    DEFF Research Database (Denmark)

    De Vis, J B; Hendrikse, J; Bhogal, A;

    2015-01-01

    INTRODUCTION: Blood oxygenation-level dependent (BOLD) magnetic resonance imaging signal changes in response to stimuli have been used to evaluate age-related changes in neuronal activity. Contradictory results from these types of experiments have been attributed to differences in cerebral blood....... A dual-echo pseudocontinuous arterial spin labeling (ASL) sequence was performed during normocapnic, hypercapnic, and hyperoxic breathing challenges. Whole brain and regional gray matter values of CBF, ASL cerebrovascular reactivity (CVR), BOLD CVR, oxygen extraction fraction (OEF), and CMRO2 were...... could potentially be explained by differences in EtCO2 . Regional CMRO2 was lower in older subjects. BOLD studies should take this into account when investigating age-related changes in neuronal activity....

  5. Existence and Uniqueness of Endemic States for the Age-structured MSEIR Epidemic Model

    Institute of Scientific and Technical Information of China (English)

    Xue-zhi Li; Geni Gupur; Guang-tian Zhu

    2002-01-01

    The existence and uniqueness of positive steady states for the age-structured MSEIR epidemic model with age-dependent transmission coefficient is considered. Threshold results for the existence of endemic states are established; under certain conditions, uniqueness is also shown.

  6. Structural hippocampal network alterations during healthy aging: A multi-modal MRI study

    Directory of Open Access Journals (Sweden)

    Amandine ePelletier

    2013-12-01

    Full Text Available While hippocampal atrophy has been described during healthy aging, few studies have examined its relationship with the integrity of White Matter (WM connecting tracts of the limbic system. This investigation examined WM structural damage specifically related to hippocampal atrophy in healthy aging subjects (n=129, using morphological MRI to assess hippocampal volume and Diffusion Tensor Imaging (DTI to assess WM integrity. Subjects with Mild Cognitive Impairment (MCI or dementia were excluded from the analysis. In our sample, increasing age was significantly associated with reduced hippocampal volume and reduced Fractional Anisotropy (FA at the level of the fornix and the cingulum bundle. The findings also demonstrate that hippocampal atrophy was specifically associated with reduced FA of the fornix bundle, but it was not related to alteration of the cingulum bundle. Our results indicate that the relationship between hippocampal atrophy and fornix FA values is not due to an independent effect of age on both structures. A recursive regression procedure was applied to evaluate sequential relationships between the alterations of these two brain structures. When both hippocampal atrophy and fornix FA values were included in the same model to predict age, fornix FA values remained significant whereas hippocampal atrophy was no longer significantly associated with age. According to this latter finding, hippocampal atrophy in healthy aging could be mediated by a loss of fornix connections. Structural alterations of this part of the limbic system, which have been associated with neurodegeneration in Alzheimer’s disease, result at least in part from the aging process.

  7. Exercise Promotes Healthy Aging of Skeletal Muscle

    DEFF Research Database (Denmark)

    Cartee, Gregory D; Hepple, Russell T; Bamman, Marcas M;

    2016-01-01

    Primary aging is the progressive and inevitable process of bodily deterioration during adulthood. In skeletal muscle, primary aging causes defective mitochondrial energetics and reduced muscle mass. Secondary aging refers to additional deleterious structural and functional age-related changes cau...

  8. Microstructural white matter changes mediate age-related cognitive decline on the Montreal Cognitive Assessment (MoCA).

    Science.gov (United States)

    Jolly, Todd A D; Cooper, Patrick S; Badwi, Syarifah Azizah Wan Ahmadul; Phillips, Natalie A; Rennie, Jaime L; Levi, Christopher R; Drysdale, Karen A; Parsons, Mark W; Michie, Patricia T; Karayanidis, Frini

    2016-02-01

    Although the relationship between aging and cognitive decline is well established, there is substantial individual variability in the degree of cognitive decline in older adults. The present study investigates whether variability in cognitive performance in community-dwelling older adults is related to the presence of whole brain or tract-specific changes in white matter microstructure. Specifically, we examine whether age-related decline in performance on the Montreal Cognitive Assessment (MoCA), a cognitive screening tool, is mediated by the white matter microstructural decline. We also examine if this relationship is driven by the presence of cardiovascular risk factors or variability in cerebral arterial pulsatility, an index of cardiovascular risk. Sixty-nine participants (aged 43-87) completed behavioral and MRI testing including T1 structural, T2-weighted FLAIR, and diffusion-weighted imaging (DWI) sequences. Measures of white matter microstructure were calculated using diffusion tensor imaging analyses on the DWI sequence. Multiple linear regression revealed that MoCA scores were predicted by radial diffusivity (RaD) of white matter beyond age or other cerebral measures. While increasing age and arterial pulsatility were associated with increasing RaD, these factors did not mediate the relationship between total white matter RaD and MoCA. Further, the relationship between MoCA and RaD was specific to participants who reported at least one cardiovascular risk factor. These findings highlight the importance of cardiovascular risk factors in the presentation of cognitive decline in old age. Further work is needed to establish whether medical or lifestyle management of these risk factors can prevent or reverse cognitive decline in old age. PMID:26511789

  9. Magnetic Resonance Imaging of the Clivus and Its Age-Related Changes in the Bone Marrow

    International Nuclear Information System (INIS)

    The clivus is a bone region between dorsum cella and foramen magnum. It can be evaluated very clearly in routine brain magnetic resonance imaging (MRI) dueto its central location. Quantitative and qualitative evaluation of the clivus and its changes according to age in a group of healthy people. The transition of clival bone marrow to fatty marrow by the increasein age is examined by MRI in 105 men and 105 women who had no clival and bone marrow pathology on MRI. The clivus/pons, clivus/CSF intensity values and clival bone marrow imaging patterns according to age groups were prospectively evaluated using a 1.5 Tesla MR device. When age groups were individually compared, there were meaningful statistical differences both in men and women in terms of clivus/CSF and clivus/pons intensity ratios (both Ps < 0.05). Clivus/pons and clivus/CSF intensity ratios were found to be increased with age in all cases. The distribution of age groups according to stages in all individuals was statistically meaningful (P < 0.05). When the appearance patterns of both genders in every ten-fold age were examined, stage III bone marrow was observed more in elder ages. As a result, besides the fact that standard ranges determined for clivus/CSF, clivus/pons intensity ratios according to age may be used in the assessment of potential pathological cases involving bone marrow; they can also be leading in the diagnosis of bone marrow diseases when taken into consideration together with clinical and laboratory data

  10. Age-related changes in visual exploratory behavior in a natural scene setting

    Directory of Open Access Journals (Sweden)

    Johanna eHamel

    2013-06-01

    Full Text Available Diverse cognitive functions decline with increasing age, including the ability to process central and peripheral visual information in a laboratory testing situation (useful visual field of view. To investigate whether and how this influences activities of daily life, we studied age-related changes in visual exploratory behavior in a natural scene setting: a driving simulator paradigm of variable complexity was tested in subjects of varying ages with simultaneous eye- and head-movement recordings via a head-mounted camera. Detection and reaction times were also measured by visual fixation and manual reaction. We considered video computer game experience as a possible influence on performance. Data of 73 participants of varying ages were analyzed, driving two different courses. We analyzed the influence of route difficulty level, age and eccentricity of test stimuli on oculomotor and driving behavior parameters. No significant age effects were found regarding saccadic parameters. In the older subjects head-movements increasingly contributed to gaze amplitude. More demanding courses and more peripheral stimuli locations, induced longer reaction times in all age groups. Deterioration of the functionally useful visual field of view with increasing age was not suggested in our study group. However, video game-experienced subjects revealed larger saccade amplitudes and a broader distribution of fixations on the screen. They reacted faster to peripheral objects suggesting the notion of a general detection task rather than perceiving driving as a central task. As the video game experienced population consisted of younger subjects, our study indicates that effects due to video game experience can easily be misinterpreted as age effects if not accounted for. We therefore view it as essential to consider video game experience in all testing methods using virtual media.

  11. The first description of oarfish Regalecus glesne (Regalecus russellii Cuvier 1816) ageing structures

    Science.gov (United States)

    Midway, S.R.; Wagner, Tyler

    2016-01-01

    Despite being a large, conspicuous teleost with a worldwide tropical and temperate distribution, the giant oarfish Regalecus spp. remain very rare fish species in terms of scientific sampling. Subsequently, very little biological information is known about Regalecus spp. and almost nothing has been concluded in the field of age and growth (Roberts, 2012). No studies of otoliths or temporal (annual) markings on any hard structures have been reported, and to our knowledge otoliths have never been recovered from any specimens (Tyson Roberts, personal communication),although a few texts do provide illustrations of Regalecus sp. otoliths (Lin and Chang, 2012; Nolf, 2013). Further inferential difficulty comes from the fact that age and growth studies of any Lampridiforme species are rare. Lampris guttatus is perhaps the only Lampridiforme species for which any biological information has been reported(Francis et al., 2004), which stems from the species commercial value. In order to begin understanding any species (for later purposes of management, conservation, etc.), basic biological information is needed. In the present study, we examine not only the first Regalecus russellii otolith, but provide suggestions toward future work that should direct data collection that can be used to generate basic biological information for this species.

  12. The impact of obesity on skeletal muscle strength and structure through adolescence to old age.

    Science.gov (United States)

    Tomlinson, D J; Erskine, R M; Morse, C I; Winwood, K; Onambélé-Pearson, Gladys

    2016-06-01

    Obesity is associated with functional limitations in muscle performance and increased likelihood of developing a functional disability such as mobility, strength, postural and dynamic balance limitations. The consensus is that obese individuals, regardless of age, have a greater absolute maximum muscle strength compared to non-obese persons, suggesting that increased adiposity acts as a chronic overload stimulus on the antigravity muscles (e.g., quadriceps and calf), thus increasing muscle size and strength. However, when maximum muscular strength is normalised to body mass, obese individuals appear weaker. This relative weakness may be caused by reduced mobility, neural adaptations and changes in muscle morphology. Discrepancies in the literature remain for maximal strength normalised to muscle mass (muscle quality) and can potentially be explained through accounting for the measurement protocol contributing to muscle strength capacity that need to be explored in more depth such as antagonist muscle co-activation, muscle architecture, a criterion valid measurement of muscle size and an accurate measurement of physical activity levels. Current evidence demonstrating the effect of obesity on muscle quality is limited. These factors not being recorded in some of the existing literature suggest a potential underestimation of muscle force either in terms of absolute force production or relative to muscle mass; thus the true effect of obesity upon skeletal muscle size, structure and function, including any interactions with ageing effects, remains to be elucidated. PMID:26667010

  13. The impact of obesity on skeletal muscle strength and structure through adolescence to old age.

    Science.gov (United States)

    Tomlinson, D J; Erskine, R M; Morse, C I; Winwood, K; Onambélé-Pearson, Gladys

    2016-06-01

    Obesity is associated with functional limitations in muscle performance and increased likelihood of developing a functional disability such as mobility, strength, postural and dynamic balance limitations. The consensus is that obese individuals, regardless of age, have a greater absolute maximum muscle strength compared to non-obese persons, suggesting that increased adiposity acts as a chronic overload stimulus on the antigravity muscles (e.g., quadriceps and calf), thus increasing muscle size and strength. However, when maximum muscular strength is normalised to body mass, obese individuals appear weaker. This relative weakness may be caused by reduced mobility, neural adaptations and changes in muscle morphology. Discrepancies in the literature remain for maximal strength normalised to muscle mass (muscle quality) and can potentially be explained through accounting for the measurement protocol contributing to muscle strength capacity that need to be explored in more depth such as antagonist muscle co-activation, muscle architecture, a criterion valid measurement of muscle size and an accurate measurement of physical activity levels. Current evidence demonstrating the effect of obesity on muscle quality is limited. These factors not being recorded in some of the existing literature suggest a potential underestimation of muscle force either in terms of absolute force production or relative to muscle mass; thus the true effect of obesity upon skeletal muscle size, structure and function, including any interactions with ageing effects, remains to be elucidated.

  14. Structure and physical technical and tactical training handball players aged 10-11 years

    OpenAIRE

    Palagin A.A.

    2014-01-01

    Purpose: to study the structural and functional relationships, physical, technical and tactical training handball aged 10-11 years. Material: the study involved 20 handball players aged 10-11 years. Results: isolated and subjected to review 55 correlations between speed, speed-strength, coordination skills and basic technical and tactical methods of the game. Consider the correlation matrix structure level of physical, technical and tactical training to handball pedagogical experiment. Found ...

  15. Scaling relations between structure and rheology of ageing casein particle gels

    OpenAIRE

    Mellema, M

    2000-01-01

    Mellema, M. (Michel), Scaling relations between structure and rheology of ageing casein particle gels , PhD Thesis, Wageningen University, 150 + 10 pages, references by chapter, English and Dutch summaries (2000).The relation between (colloidal) interactions, structure and rheology of particle gels is discussed, especially the properties and the spontaneous ageing behavior of rennet-induced casein(ate) or skim milk gels.Methods involved were Brownian dynamics simulations, confocal microscopy,...

  16. Compact attractors for time-periodic age-structured population models

    Directory of Open Access Journals (Sweden)

    Pierre Magal

    2001-10-01

    Full Text Available In this paper we investigate the existence of compact attractors for time-periodic age-structured models. So doing we investigate the eventual compactness of a class of abstract non-autonomous semiflow (non necessarily periodic. We apply this result to non-autonomous age-structured models. In the time periodic case, we obtain the existence of a periodic family of compact subsets that is invariant by the semiflow, and attract the solutions of the system.

  17. Structural integrity and management of aging in internal components of BWR reactors

    International Nuclear Information System (INIS)

    Presently work the bases to apply structural integrity and the handling of the aging of internal components of the pressure vessel of boiling water reactors of water are revised and is carried out an example of structural integrity in the horizontal welding H4 of the encircling one of the core of a reactor, taking data reported in the literature. It is also revised what is required to carry out the handling program or conduct of the aging (AMP). (Author)

  18. Developmental changes in consistency of preferential feeling for peers and objects around age four.

    Science.gov (United States)

    Uehara, Izumi

    2004-02-01

    When do young children come to have an individual mental image of each peer? Forming a stable impression of each person requires maturation of at least two cognitive abilities, inferring the other's mind and episodic memory. According to past studies, the critical period for both these abilities is around age four. Thus, it was hypothesized that the child begins to form a consistent mental image of each peer at or after age four. To test this hypothesis, the temporal consistency of preference for peers was examined in 3-, 4-, and 5-yr.-olds. Each subject was asked "Who do you like better than others in this class?" once a week for three times (Study 1). The results indicated that most of the 3-yr.-olds answered different names as their favorite friends or nonsense things inconsistently week by week, whereas older children tended to answer the same names across weeks. However, changing the question to "Which object do you like best of these alternatives?" dramatically changed the response pattern (Study 2): preferences among nonhuman objects (playthings) were temporally consistent even for 3-yr.-olds. These results indicate that children before age four do have a temporally consistent feeling toward general objects but do not have a consistent firm feeling about personal relationships among peers. The results are discussed in relation to the critical developmental changes about age 4 in other cognitive abilities.

  19. Developmental changes in consistency of preferential feeling for peers and objects around age four.

    Science.gov (United States)

    Uehara, Izumi

    2004-02-01

    When do young children come to have an individual mental image of each peer? Forming a stable impression of each person requires maturation of at least two cognitive abilities, inferring the other's mind and episodic memory. According to past studies, the critical period for both these abilities is around age four. Thus, it was hypothesized that the child begins to form a consistent mental image of each peer at or after age four. To test this hypothesis, the temporal consistency of preference for peers was examined in 3-, 4-, and 5-yr.-olds. Each subject was asked "Who do you like better than others in this class?" once a week for three times (Study 1). The results indicated that most of the 3-yr.-olds answered different names as their favorite friends or nonsense things inconsistently week by week, whereas older children tended to answer the same names across weeks. However, changing the question to "Which object do you like best of these alternatives?" dramatically changed the response pattern (Study 2): preferences among nonhuman objects (playthings) were temporally consistent even for 3-yr.-olds. These results indicate that children before age four do have a temporally consistent feeling toward general objects but do not have a consistent firm feeling about personal relationships among peers. The results are discussed in relation to the critical developmental changes about age 4 in other cognitive abilities. PMID:15077787

  20. Ageing Voices: The Effect of Changes in Voice Parameters on ASR Performance

    Directory of Open Access Journals (Sweden)

    Ravichander Vipperla

    2010-01-01

    Full Text Available With ageing, human voices undergo several changes which are typically characterized by increased hoarseness and changes in articulation patterns. In this study, we have examined the effect on Automatic Speech Recognition (ASR and found that the Word Error Rates (WER on older voices is 10% absolute higher compared to those of adult voices. Subsequently, we compared several voice source parameters including fundamental frequency, jitter, shimmer, harmonicity, and cepstral peak prominence of adult and older males. Several of these parameters show statistically significant difference for the two groups. However, artificially increasing jitter and shimmer measures do not effect the ASR accuracies significantly. Artificially lowering the fundamental frequency degrades the ASR performance marginally but this drop in performance can be overcome to some extent using Vocal Tract Length Normalisation (VTLN. Overall, we observe that the changes in the voice source parameters do not have a significant impact on ASR performance. Comparison of the likelihood scores of all the phonemes for the two age groups show that there is a systematic mismatch in the acoustic space of the two age groups. Comparison of the phoneme recognition rates show that mid vowels, nasals, and phonemes that depend on the ability to create constrictions with tongue tip for articulation are more affected by ageing than other phonemes.