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At least 19 recordsLinked to original sources
PubMed2006

Diversity in HIV-1 envelope V1-V3 sequences early in infection reflects sequence diversity throughout the HIV-1 genome but does not predict the extent of sequence diversity during chronic infection.

Differences in the extent of genetic diversity have been observed in human immunodeficiency virus type-1 (HIV-1) envelope sequences early in infection, and this has been linked to gender and to modifiable exogenous factors such as hormonal contraceptive use and genital tract infections. But it is unclear whether envelope diversity is indicative of diversity in other regions of the viral genome, and thus whether it adequately reflects whether multiple or a single virus initiated the infection. Here we show that six women with homogeneous envelope V1-V3 sequences during primary infection also had homogeneous gag and polymerase (pol) sequences at the same time. On the other hand, six women with multiple envelope sequences had diverse gag and pol genotypes during a similar interval after infection. This suggests that envelope sequences reflect sequence diversity throughout the viral genomes present early in infection and thus provide an indication of whether a single virus or multiple viruses initiated the infection. Analysis of HIV-1 sequences from about 3 years after infection revealed that the level of diversity and diversification was similar between the women in the two groups.

Chronic Disease↗
PubMed2000

Diverse CD1d-restricted T cells: diverse phenotypes, and diverse functions.

Invariant CD1d-restricted T cells express NK cell markers and use a limited TCR repertoire. Here, we describe a second CD1d-restricted T cell subset that uses a diverse TCR repertoire. These T cells can also express NK cell markers and function similarly to invariant T cells. The antigens recognized by the diverse subset are likely to be different from those recognized by invariant TCRs. The variable NK1.1 antigen expression on these T cell populations limits its usefulness in identifying CD1d-restricted T cells. Lastly, the discovery of antigens recognized by diverse CD1d-restricted T cells will provide insight into their role in normal and pathological immune responses.

Animals↗
PubMed2005

Species diversity and genetic diversity: parallel processes and correlated patterns.

Species diversity and genetic diversity may be correlated as a result of processes acting in parallel at the two levels. However, no theories predict the conditions under which different relationships between species diversity and genetic diversity might arise and therefore when one level of diversity may be predicted using the other. I used simulation models to investigate the parallel influence of locality area, immigration rate, and environmental heterogeneity on species diversity and genetic diversity. The most common pattern was moderate to strong positive species-genetic diversity correlations (SGDCs). Such correlations may be driven by any one of the three locality characteristics examined, but important exceptions and patterns emerged. Genetic diversity and species diversity were more weakly correlated when genetic diversity was measured for rare versus common species. Environmental heterogeneity not only imposes spatially varying selection on populations and communities but also causes changes in species' population sizes and therefore genetic diversity; these interacting processes can create positive, negative, or unimodal relationships of genetic diversity with species diversity. When species are considered as part of multispecies communities, predictions from single-species models of genetic diversity apply in some instances (effects of area and immigration) but often not in others (effects of environmental heterogeneity).

Biodiversity↗
PubMedDate not supplied

Commitment to diversity. A system's diversity program prepares it for the future.

Three years ago the president/chief executive officer of Franciscan Health System of Cincinnati, Inc., developed a vision in which diversity would be the key to a major cultural shift of the organization. In April 1993 the system formed a Diversity Steering Committee to establish an infrastructure for a healthy, multicultural environment. The committee outlined two key objectives: to develop consensus around a vision of diversity for the organization, and to conduct research to determine the organizational culture with regard to diversity issues. By 1994 diversity had become one of the system's 10 strategic initiatives, and a Diversity Department had been added to the corporate structure. The Diversity Steering Committee developed a three-year management action plan that includes seven major goals: Demonstrate the corporate commitment to diversity Educate, train, build, and support a diverse organization Communicate the importance of diversity Create a diverse work force Track diversity progress Establish accountability for diversity implementation Build loyalty with diverse external customers.

Consumer Behavior↗
PubMed2002

Effects of above-ground plant species composition and diversity on the diversity of soil-borne microorganisms.

A coupling of above-ground plant diversity and below-ground microbial diversity has been implied in studies dedicated to assessing the role of macrophyte diversity on the stability, resilience, and functioning of ecosystems. Indeed, above-ground plant communities have long been assumed to drive below-ground microbial diversity, but to date very little is known as to how plant species composition and diversity influence the community composition of micro-organisms in the soil. We examined this relationship in fields subjected to different above-ground biodiversity treatments and in field experiments designed to examine the influence of plant species on soil-borne microbial communities. Culture-independent strategies were applied to examine the role of wild or native plant species composition on bacterial diversity and community structure in bulk soil and in the rhizosphere. In comparing the influence of Cynoglossum officinale (hound's tongue) and Cirsium vulgare (spear thistle) on soil-borne bacterial communities, detectable differences in microbial community structure were confined to the rhizosphere. The colonisation of the rhizosphere of both plants was highly reproducible, and maintained throughout the growing season. In a separate experiment, effects of plant diversity on bacterial community profiles were also only observed for the rhizosphere. Rhizosphere soil from experimental plots with lower macrophyte diversity showed lower diversity, and bacterial diversity was generally lower in the rhizosphere than in bulk soil. These results demonstrate that the level of coupling between above-ground macrophyte communities and below-ground microbial communities is related to the tightness of the interactions involved. Although plant species composition and community structure appear to have little discernible effect on microbial communities inhabiting bulk soil, clear and reproducible changes in microbial community structure and diversity are observed in the rhizosphere.

Bacteria↗
PubMed2006

Resource availability controls fungal diversity across a plant diversity gradient.

Despite decades of research, the ecological determinants of microbial diversity remain poorly understood. Here, we test two alternative hypotheses concerning the factors regulating fungal diversity in soil. The first states that higher levels of plant detritus production increase the supply of limiting resources (i.e. organic substrates) thereby increasing fungal diversity. Alternatively, greater plant diversity increases the range of organic substrates entering soil, thereby increasing the number of niches to be filled by a greater array of heterotrophic fungi. These two hypotheses were simultaneously examined in experimental plant communities consisting of one to 16 species that have been maintained for a decade. We used ribosomal intergenic spacer analysis (RISA), in combination with cloning and sequencing, to quantify fungal community composition and diversity within the experimental plant communities. We used soil microbial biomass as a temporally integrated measure of resource supply. Plant diversity was unrelated to fungal diversity, but fungal diversity was a unimodal function of resource supply. Canonical correspondence analysis (CCA) indicated that plant diversity showed a relationship to fungal community composition, although the occurrence of RISA bands and operational taxonomic units (OTUs) did not differ among the treatments. The relationship between fungal diversity and resource availability parallels similar relationships reported for grasslands, tropical forests, coral reefs, and other biotic communities, strongly suggesting that the same underlying mechanisms determine the diversity of organisms at multiple scales.

Biodiversity↗
PubMed2006

Estimation of breed contributions to present and future genetic diversity of 44 North Eurasian cattle breeds using core set diversity measures.

Extinction of breeds threatens genetic diversity of livestock species. The need to conserve genetic diversity is widely accepted but involves in general two questions: (i) is the expected loss of diversity in a set of breeds within a defined future time horizon large enough to establish a conservation plan, and if so (ii) which breeds should be prioritised for such a conservation plan? The present study uses a marker assisted methodology to address these questions. The methodology combines core set diversity measures with a stochastic method for the estimation of expected future diversity and breed marginal diversities. The latter is defined as the change in the total diversity of all breeds caused by a one unit decrease in extinction probability of a particular breed. The stochastic method was validated by means of simulations. A large field data set consisting of 44 North Eurasian cattle breeds was analysed using simplified determined extinction probabilities. The results show that the expected loss of diversity in this set within the next 20 to 50 years is between 1 and 3% of the actual diversity, provided that the extinction probabilities which were used are approximately valid. If this loss is to be reduced, it is sufficient to include those three to five breeds with the highest marginal diversity in a conservation scheme.

Animals↗
PubMed1994

Workplace diversity: a leadership challenge. Managing diversity is a social, financial, and moral imperative.

Fostering workplace diversity is about building an organizational culture that embraces personal differences and encourages heterogeneous persons to work together toward a common end. Setting in motion the transition to a more inclusive and productive workplace is an uncommon challenge and the primary responsibility of leaders, especially in Catholic healthcare. The origins of diversity can be found in creation itself. Not only are we united as a people of God and as members of the body of Christ, we are bound together through our shared humanity. Three values are especially relevant to promoting diversity in the workplace: respect for human dignity, the common good, and distributive justice as participation in the common good. Economic incentives strengthen the theological and moral motives for developing a diverse work force. Organizations' financial success will depend ultimately on how well diversity is integrated into the organizational culture. As a process, managing diversity enables healthcare leaders to discover new ways to develop the potential of all employees and at the same time improve performance and production. At the heart of managing diversity lies the reform of internal systems, structures, and processes. Managing diversity also requires the transformation of the organization's culture. Initiatives that are useful for setting a positive future course include conducting a cultural audit, establishing a cultural diversity task force, and putting in place a diversity "champion" who is accountable directly to the chief executive officer.

Catholicism↗
PubMed2003

Partitioning species diversity across landscapes and regions: a hierarchical analysis of alpha, beta, and gamma diversity.

Species diversity may be additively partitioned within and among samples (alpha and beta diversity) from hierarchically scaled studies to assess the proportion of the total diversity (gamma) found in different habitats, landscapes, or regions. We developed a statistical approach for testing null hypotheses that observed partitions of species richness or diversity indices differed from those expected by chance, and we illustrate these tests using data from a hierarchical study of forest-canopy beetles. Two null hypotheses were implemented using individual- and sample-based randomization tests to generate null distributions for alpha and beta components of diversity at multiple sampling scales. The two tests differed in their null distributions and power to detect statistically significant diversity components. Individual-based randomization was more powerful at all hierarchical levels and was sensitive to departures between observed and null partitions due to intraspecific aggregation of individuals. Sample-based randomization had less power but still may be useful for determining whether different habitats show a higher degree of differentiation in species diversity compared with random samples from the landscape. Null hypothesis tests provide a basis for inferences on partitions of species richness or diversity indices at multiple sampling levels, thereby increasing our understanding of how alpha and beta diversity change across spatial scales.

Animals↗
PubMed1992

Long-term metabolic effects of urinary diversion: a comparison of myelomeningocele patients managed by clean intermittent catheterization and urinary diversion.

We previously reported that chronic urinary diversion through intestinal segments may have adverse effects on bone and mineral metabolism. This study examined the long-term health of patients managed by urinary diversion (94% by ileal conduit) for neuropathic bladders secondary to myelomeningocele defects and compared them to a control population of myelomeningocele patients managed by intermittent catheterization. Of the patients 93 were studied by personal interview, chart review, morphometric analysis, serum studies and dual-photon bone density determination. Average followup was 23 +/- 6 years in the urinary diversion group and 17 +/- 5 years in the intermittent catheterization group. Fractures occurred in 40% of the patients in both groups. Patients with a urinary diversion had an increased need for surgery to correct spinal curvature (57% versus 40%) and a significantly increased incidence of complications resulting from orthopedic procedures (17% versus 3%, p less than or equal to 0.05). There was also an adverse effect on renal function. The urinary diversion group had an increased incidence of radiographic renal deterioration (57% versus 8%, p less than 0.001), nephrolithiasis (43% versus 2%, p less than 0.001), pyelonephritis (60% versus 21%, p less than 0.001) and intermittent metabolic acidosis (20% versus 5%, p = 0.05). Surgery was required in 37% for stomal complications and in 17% for ureterointestinal stricture. Linear growth was adversely affected by urinary diversion. Patients with urinary diversion had decreased lengths for all morphometric parameters and a greater percentage of them were at or below the 10th percentile standards. Serum electrolytes, liver function studies, vitamin D3 and parahormone showed no differences in the 2 groups. No patient had a significant metabolic acidosis at the time of study. Bone densities were significantly diminished in both groups and not significantly different. This study strongly suggests that urinary diversion through intestinal segments is associated with adverse effects on bone health.

Bone Density↗
PubMed1994

Health-related quality of life after urinary diversion: continent diversion with the Kock pouch compared with ileal conduit. A questionnaire study.

A questionnaire study was carried out to compare the health-related quality of life after continent urinary diversion using a Kock pouch with that following ileal conduit diversion. 76 patients completed the questionnaire: 26 patients had a continent and 50 an ileal conduit diversion, median follow-up was 0.9 year (range 0.5-4.4) and 4.9 years (range 2.4-14.7), respectively. The type of operation carried significant relation to the presence of leakage distress associated with urine leakage; 78% among conduit patients versus 50% among continent diversion patients experienced distress. Physical contact between patient and partner was reduced significantly less following continent diversion: 16% against 43% among patients with conduit diversion. Global satisfaction with life was high and similar in the two groups. Continent urinary diversion appears to be superior to conventional ileal conduit diversion.

Aged↗
PubMed2004

Genetic diversity of Ranunculus acris L. (Ranunculaceae) populations in relation to species diversity and habitat type in grassland communities.

Correlates between genetic diversity at intra- and interpopulation levels and the species diversity in plant communities are rarely investigated. Such correlates may give insights into the effect of local selective forces across different communities on the genetic diversity of local plant populations. This study has employed amplified fragment length polymorphism to assess the genetic diversity within and between 10 populations of Ranunculus acris in relation to the species diversity (richness and evenness) of grassland communities of two different habitat types, 'seminatural' and 'agriculturally improved', located in central Germany. Within-population genetic diversity estimated by Nei's unbiased gene diversity (HE) was high (0.258-0.334), and was not correlated with species richness (Pearson's r = -0.17; P = 0.64) or species evenness (Pearson's r = 0.15; P = 0.68) of the plant communities. However, the genetic differentiation between R. acris populations was significantly correlated with the difference in species evenness (Mantel's r = 0.62, P = 0.02), but not with difference in species richness of plant communities (r = -0.17, P = 0.22). Moreover, we also found that populations of R. acris from the 'seminatural' habitat were genetically different (amova, P < 0.05) from those in 'agriculturally improved' habitats, suggesting that gene flow between these habitat types is limited. The results reported in this study may indicate that habitat characteristics influence the genetic diversity of plant species.

Analysis of Variance↗
PubMed1993

Relative indications for orthotopic lower urinary tract reconstruction, continent urinary diversion and conduit urinary diversion.

Continent urinary diversion has become increasingly popular in the last few years and there are now several situations in which ileal conduit diversion, continent diversion and orthotopic reconstruction of the lower urinary tract are equally valid options. This review was intended to determine specific indications for each. Of 513 patients treated for severe lower urinary tract problems in the last 10 years, 399 underwent orthotopic reconstruction, 68 underwent continent diversion and 46 had an ileal conduit. Problems occurred 2 to 3 times more commonly in the continent diversion group than in either of the other groups. Given a free choice, most patients would choose an orthotopic reconstruction and this should probably be regarded as the gold standard. Continent diversion is specifically indicated in male patients who require a total cystourethrectomy for bladder cancer, in severe post-radiotherapy problems, and in patients with neuropathic bladder dysfunction in whom, for various reasons, self-catheterisation is impossible. Ileal conduit diversion remains the simplest and safest technique in high-risk patients and does not preclude a subsequent continent diversion or orthotopic reconstruction.

Humans↗
PubMed2004

Enigmatic biodiversity correlations: ant diversity responds to diverse resources.

A pattern noted in ecology is that diversity at one level begets diversity at other levels. In the case of consumers competing for similar resources, the diversity of those resources is thought to provide some degree of niche diversification in which a diverse set of consumer species can coexist. If, however, the diverse resources are not sufficiently distinct from one another, from the standpoint of the consumer species, such niche diversification will not exist. We experimentally show that a diverse array of twigs attracted 80% more species of twig-nesting ants than a monospecific collection of twigs. The specific tree species from which the twigs were derived did not explain the pattern. It appears that diversity per se at one level (twigs) creates conditions that promote diversity at another level (nesting ants).

Animals↗
PubMed2006

Diversity begets diversity: host expansions and the diversification of plant-feeding insects.

BACKGROUND: Plant-feeding insects make up a large part of earth's total biodiversity. While it has been shown that herbivory has repeatedly led to increased diversification rates in insects, there has been no compelling explanation for how plant-feeding has promoted speciation rates. There is a growing awareness that ecological factors can lead to rapid diversification and, as one of the most prominent features of most insect-plant interactions, specialization onto a diverse resource has often been assumed to be the main process behind this diversification. However, specialization is mainly a pruning process, and is not able to actually generate diversity by itself. Here we investigate the role of host colonizations in generating insect diversity, by testing if insect speciation rate is correlated with resource diversity. RESULTS: By applying a variant of independent contrast analysis, specially tailored for use on questions of species richness (MacroCAIC), we show that species richness is strongly correlated with diversity of host use in the butterfly family Nymphalidae. Furthermore, by comparing the results from reciprocal sister group selection, where sister groups were selected either on the basis of diversity of host use or species richness, we find that it is likely that diversity of host use is driving species richness, rather than vice versa. CONCLUSION: We conclude that resource diversity is correlated with species richness in the Nymphalidae and suggest a scenario based on recurring oscillations between host expansions - the incorporation of new plants into the repertoire - and specialization, as an important driving force behind the diversification of plant-feeding insects.

Animals↗
PubMed1997

Quality of life and health in patients with urinary diversion: a comparison of incontinent versus continent urinary diversion.

OBJECTIVE: To compare the quality of life and health in patients with incontinent and continent urinary diversions, in correlation with the initial diagnosis, diversion-related symptoms, psychological status and employment status. MATERIALS AND METHODS: 81 patients (64% male and 36% female) with a mean age of 55 years (18-65 years) were included in this retrospective study. A total of 27 had an incontinent urinary diversion (group A) and 54 a continent diversion (group B). The initial diagnosis was malignant tumor in 75% (n = 61) and nontumor disease in 25% (n = 20). A structured interview and psychometric instrument assessment of the quality of life as well as somatic and psychological symptoms were carried out and analyzed. RESULTS: Patients with nontumor disease, a continent reservoir and employment tended to have the highest level of quality of life. The higher the number and severity of psychological symptoms, such as depression and anxiety, the lower the level of global satisfaction with life, health and urinary diversion, and vice versa. No difference was seen between groups A and B concerning diversion-related symptoms, global satisfaction with life and health and sociodemographic data. CONCLUSIONS: The decision for a continent versus an incontinent urinary diversion must consider not only the medical factors of each individual patient, but also the initial diagnosis, psychological condition and employment status.

Adaptation, Psychological↗
PubMed2006

Immunoglobulin is a highly diverse self-molecule that improves cellular diversity and function during immune reconstitution.

Paradoxically, human B cell immune deficiencies are associated with increased susceptibility to viral and fungi infections, which are T cell immunity related infections. Also, some viral infections occurring in immune depressed patients such as cytomegalovirus infections are recommended to be treated with intravenous immunoglobulin (IVIg) in combination with antiviral therapy. This fact has no clear biological explanation but it has been shown to be successful. Recently, B cells and immunoglobulin were identified as essential elements driving T cell receptor (TCR) diversity generation. Idiotype peptides of B cell immunoglobulin may be the driving force for the antigen presenting function of B cells and other antigen presenting cells to influence the T cell repertoire. This seems to be another relevance of Jerne's idiotypic network and another function of immunoglobulin. Since T cells function depends on the diversity of the TCR repertoire, means to increase the diversity of the T cell repertoire may improve T cell function in situations characterized by a contracted TCR repertoire, such as AIDS, primary immunodeficiency, cancer, autoimmunity and following chemotherapy and hematopoietic precursors transplantation. The clinical hypothesis here put forward is that B cells and/or immunoglobulin may be used therapeutically aiming to increase and potentially to restore T cell repertoire diversity improving T cell function in situations implicating a contracted T cell repertoire. The fact that immunoglobulin influence the composition of T cell repertoire by increasing its diversity allows a much wider application of this molecule in the clinical practice. Here is presented a novel reasoning for the use of IVIg in humans, which should be explored. All the situations where immune reconstitution occurs are potentially a target for this therapeutically mechanism, aiming to fast and improve the diversity of the reconstituted immune repertoires. This new role of Ig molecule, an old and widely therapeutically used molecule, may help to explain several effects that IVIg have in the T cell compartment, such as modulation of the activation and function of effectors T cells. The idea that immunoglobulin is essential in the generation and maintenance of a diverse compartment of T cells, affecting T cell function via that mechanism suggests a promising approach to medical conditions involving immune reconstitution. Furthermore, it represents a new paradigm of understanding the immune system as a complex, interdependent web of cells/cell products that inter-affect each other generation, function and survival.

Animals↗