66 research outputs found

    Intersection of ecosystem and biodiversity concerns in the management of rangelands

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    Maintenance of ecological functions and disturbance regimes within ecosystems is as important as preserving species populations or their genetic structure, biotic communities, and landscapes. There is considerable dispute as to how species diversity influences productivity and stability of various ecosystem structural and dynamic attributes. Some view each and every species as making an incremental contribution to these features. Others assume that some redundancy exists. Addition or loss of species can be anecdotally shown to influence ecosystems in proportion to the role such organisms. Subtle but essential interactions are easy to overlook, however. We should try to keep all the parts until more definitive research is available on this topic. Sustainable development will require balancing resource use with maintenance of our natural legacies. Ecosystem perspectives must contribute to decisions on where the balance exists

    Bone Response to Fluoride Exposure Is Influenced by Genetics

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    Genetic factors influence the effects of fluoride (F) on amelogenesis and bone homeostasis but the underlying molecular mechanisms remain undefined. A label-free proteomics approach was employed to identify and evaluate changes in bone protein expression in two mouse strains having different susceptibilities to develop dental fluorosis and to alter bone quality. In vivo bone formation and histomorphometry after F intake were also evaluated and related to the proteome. Resistant 129P3/J and susceptible A/J mice were assigned to three groups given low-F food and water containing 0, 10 or 50 ppmF for 8 weeks. Plasma was evaluated for alkaline phosphatase activity. Femurs, tibiae and lumbar vertebrae were evaluated using micro-CT analysis and mineral apposition rate (MAR) was measured in cortical bone. For quantitative proteomic analysis, bone proteins were extracted and analyzed using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS), followed by label-free semi-quantitative differential expression analysis. Alterations in several bone proteins were found among the F treatment groups within each mouse strain and between the strains for each F treatment group (ratio ≥1.5 or ≤0.5; p<0.05). Although F treatment had no significant effects on BMD or bone histomorphometry in either strain, MAR was higher in the 50 ppmF 129P3/J mice than in the 50 ppmF A/J mice treated with 50 ppmF showing that F increased bone formation in a strain-specific manner. Also, F exposure was associated with dose-specific and strain-specific alterations in expression of proteins involved in osteogenesis and osteoclastogenesis. In conclusion, our findings confirm a genetic influence in bone response to F exposure and point to several proteins that may act as targets for the differential F responses in this tissue

    Starburst in HS 0822+3542 induced by the very blue LSB dwarf SAO 0822+3545

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    (Abridged). One of the most metal-deficient blue compact galaxies (BCGs) HS 0822+3542 (Z=1/34 Zsun), is also one of the nearest such objects. A trigger mechanism for its current SF burst has remained unclear. We report the discovery of a very blue ((B-V)tot=0.08 and (V-R)tot=0.14) LSB (mu_B^0 > 23.4 arcsec^-2) dwarf irregular (dIrr) galaxy, named SAO 0822+3545. Its small relative velocity and projected distance of ~11 kpc from the BCG imply their physical association. For this LSB galaxy, we present spectroscopic results, total B,V,R magnitudes, the effective radii and surface brightness (SB), and we describe its morphological properties. We compare the very blue colours of this dwarf with PEGASE.2 models of the colour evolution of a Z=1/20 Zsun stellar population, and combine this analysis with the data on the LSBD EW(Ha) values. The models best describing all available observational data depend on the relative fraction of massive stars in the IMF used. For a Salpeter IMF with Mup = 120 Msun, the best model includes a "young" single stellar population (SSP) with an age of ~10 Myr and an "old" SSP with the age of ~0.2--10 Gyr. The mass ratio of the old to young components should be in the range of 10 to 30. The role of interaction in triggering the galaxies major SF episodes during the last ~100-200 Myr is discussed. For the BCG, based on the spectroscopy with the 6m telescope, we estimate the physical parameters of its SF region and present the first evidence of an ionized gas supershell. This pair of dwarfs lies deep within the nearby Lynx-Cancer void, with the nearest bright (L > L*) galaxies at distances > 3 Mpc. This is probably one of the main factors responsible for the unevolved state of HS 0822+3542.Comment: 17 pages, 9 figures, accepted to A&

    Abnormal oscillatory brain dynamics in schizophrenia: a sign of deviant communication in neural network?

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    <p>Abstract</p> <p>Background</p> <p>Slow waves in the delta (0.5–4 Hz) frequency range are indications of normal activity in sleep. In neurological disorders, focal electric and magnetic slow wave activity is generated in the vicinity of structural brain lesions. Initial studies, including our own, suggest that the distribution of the focal concentration of generators of slow waves (dipole density in the delta frequency band) also distinguishes patients with psychiatric disorders such as schizophrenia, affective disorders, and posttraumatic stress disorder.</p> <p>Methods</p> <p>The present study examined the distribution of focal slow wave activity (ASWA: abnormal slow wave activity) in116 healthy subjects, 76 inpatients with schizophrenic or schizoaffective diagnoses and 42 inpatients with affective (ICD-10: F3) or neurotic/reactive (F4) diagnoses using a newly refined measure of dipole density. Based on 5-min resting magnetoencephalogram (MEG), sources of activity in the 1–4 Hz frequency band were determined by equivalent dipole fitting in anatomically defined cortical regions.</p> <p>Results</p> <p>Compared to healthy subjects the schizophrenia sample was characterized by significantly more intense slow wave activity, with maxima in frontal and central areas. In contrast, affective disorder patients exhibited less slow wave generators mainly in frontal and central regions when compared to healthy subjects and schizophrenia patients. In both samples, frontal ASWA were related to affective symptoms.</p> <p>Conclusion</p> <p>In schizophrenic patients, the regions of ASWA correspond to those identified for gray matter loss. This suggests that ASWA might be evaluated as a measure of altered neuronal network architecture and communication, which may mediate psychopathological signs.</p

    The experience of palliative patients and their families of a family meeting utilised as an instrument for spiritual and psychosocial care: A qualitative study

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    Background: This study explores the experience of palliative patients and their family members of a family meeting model, utilised as an instrument for the provision of spiritual and psychosocial care. In doing so the study embraces a broad understanding of spirituality which may or may not include formal religious practice and a concept of psychosocial care that includes: social and emotional well-being, communication, self esteem, mental health and adaptation to illness. The meeting of spiritual and psychosocial needs is considered to be an important aspect of palliative care. Methods. This qualitative study, philosophically underpinned by hermeneutic phenomenology, investigates the participatory experience of palliative care patients and their significant family members of such a family meeting. People registered with two large metropolitan palliative care services, who met selection criteria, were referred by medical staff. Twelve of the 66 referred took part in family meetings which also included significant others invited by the patient. A total of 36 family members participated. The number of participants of individual family meetings ranged from two to eleven. After the family meeting every participant was invited to take part in an individual in-depth interview about their experience of the meeting. Forty seven interviews were conducted. These were audio recorded and transcribed. Results: Data analysis, utilising Ricoeur's theory of interpretation, revealed seven main themes: personal experience of the meeting, personal outcomes, observation of others' experience, observation of experience and outcomes for the family unit, meeting facilitation, how it could have been different and general applicability of the family meeting. Throughout these themes were numerous references to aspects of the web of relationships which describe the concept of spirituality as it is defined for the purpose of this study. Conclusions: The findings indicate the potential of the type of family meeting reported for use in the spiritual and psychosocial care of people receiving palliative care and their families. However further research is needed to explore its application to more culturally diverse groups and its longer term impact on family members.Heather M Tan, Anne Wilson, Ian Olver and Christopher Barto

    Jornada Validation Site Report

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    Jornada Validation Site

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    The Jornada Validation Site (Playa- NMSU Ranch) Validation Study

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    Disturbances by desert rodents are more strongly associated with spatial changes in soil texture than woody encroachment

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    Abstract Background and Aims Soil texture is an important determinant of ecosystem structure and productivity in drylands, and may influence animal foraging and, indirectly, plant community composition. Methods We measured the density and composition of surface disturbances (foraging pits) of small, soilforaging desert vertebrates in shrubland and grasslands, both with coarse-and fine-textured soils. We predicted that the density and functional significance of disturbances would be related more to differences in texture than shrub encroachment. Results Soil texture had a stronger influence on animal foraging sites than shrub encroachment. There were more disturbances, greater richness and abundance of trapped seed, and greater richness of germinating plants on coarse-than fine-textured soils. Pits in coarse soils trapped 50 % more litter than those in finer soils. Apart from slightly more soil removal and greater litter capture in shrubland pits, there were no effects of encroachment. Conclusions Although the process of woody encroachment has been shown to have marked effects on some ecosystem properties, it is likely to have a more subordinate effect on surface disturbances and therefore their effects on desert plant communities than soil texture. Our results highlight the importance of animal activity in shaping desert plant communities, and potentially, in maintaining or reinforcing shrub dominant processes
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