877 research outputs found
Toward in vitro fertilization in Brachiaria spp.
Brachiaria are forage grasses widely cultivated in tropical areas. In vitro pollination was applied to accessions of Brachiaria spp. by placing pollen of non-dehiscent anthers on a solid medium near isolated ovaries. Viability and in vitro germination were tested in order to establish good conditions for pollen development. Comparing sexual to apomictic plants, apomictic pollen has more abortion after meiosis during the microspore stage and a lower viability and, of both types, only some plants have sufficient germination in a high sugar concentration. Using in vitro pollination with the sexual plant, the pollen tube penetrates into the nucellus and micropyle, but the embryo sac degenerates and collapses. In the apomictic B. decumbens, in vitro pollination leads to the transfer of the sperm nuclei into the egg cell and the central cell. The results are discussed according to normal fertilization and barriers in sexual and apomictic plants
Check-list of European Orthoptera
List of all 974 recognized species of Ensifera (Tettigonioidea: 458, Rhaphidophoroidea: 44, Grylloidea: 91) and Caelifera (Tetrigoidea: 12, Tridactyloidea: 6, Acridoidea: 363) in Europe including information about their distribution.Aufstellung aller 974 derzeitig anerkannten Arten der Ensifera (Tettigonioidea: 458, Rhaphidophoroidea: 44, Grylloidea: 91) and Caelifera (Tetrigoidea: 12, Tridactyloidea: 6, Acridoidea: 363) in Europa mit Angabe der Verbreitungsgebiete
The relationship between small-scale nursing home care for people with dementia and staff's perceived job characteristics
Background: Over the past few decades, new care models that are more resident-oriented and directed toward small-scale and homelike environments have been developed worldwide. The impact of these care models on the quality of life of residents has been studied. However, little research has been conducted to gain insight into how these new care models influence healthcare staff's work environment. This study focuses on the consequences of small-scale care on staff's perceived job characteristics. Methods: Data were derived from a sample of 136 Dutch living arrangements providing nursing home care for people with dementia (2008/2009), in which 1,327 residents and 1,147 staff participated. The relationship between two indicators of small-scale care (small-scale care characteristics and total number of residents with dementia in facility) and staff's job characteristics (job demands, decision authority, coworker and supervisor support) were studied with multilevel regression analyses. All analyses were adjusted for staff, resident, and living arrangement characteristics when needed. Results: Both indicators of small-scale care were associated with job demands; staff perceived less time and work pressure as more characteristics of small-scale care were integrated and the facility had less residents with dementia in total. Only one indicator was associated with decision authority. As more characteristics of small-scale care were integrated, staff's perceived decision authority was higher. No relationship was found with coworker and supervisor social support. Conclusions: Knowing that job demands and decision authority are important predictors of job appraisal and well-being, our findings show that small-scale care could have a beneficial impact on healthcare staff's work environment. Copyright © International Psychogeriatric Association 2014
The use of Raman spectroscopy in the epidemiology of methicillin-resistant Staphylococcus aureus of human- and animal-related clonal lineages
AbstractIn order to perform a cost-effective search and destroy policy for methicillin-resistant Staphylococcus aureus (MRSA), a quick and reliable typing method is essential. In an area with a high level of animal-related MRSA ST398, pulsed field gel electrophoresis (PFGE) typing and spa-typing are not sufficient to discriminate between co-incidental findings and true transmission of MRSA. This study is the first to retrospectively show the performance of Raman spectroscopy in 16 well-documented outbreaks. We analysed 525 isolates, 286 MRSA ST398 and 239 from other PFGE clusters with Raman spectroscopy. When epidemiologically linked isolates from the outbreaks were analysed with PFGE as the reference standard, Raman spectroscopy correctly identified 97% of cases that were indistinguishable from the index case. With Raman cluster analysis, the most dominant distinction was between MRSA ST398 and other MRSA of human clonal lineages. Within MRSA ST398, 22 different Raman clusters were identified. Raman typing correctly identified an ST398 (spa type t567) outbreak in a hospital setting. No direct correlation was observed between Raman clusters and spa types. We conclude that Raman spectroscopy is a quick and reliable method of MRSA typing, which can be used in outbreak settings and it is comparable to PFGE, with the added advantage that PFGE non-typeable isolates can also be readily typed using the same sample preparation protocol
Respiratory impedance in healthy unsedated South African infants: Effects of maternal smoking
Background and objective: Non-invasive techniques for measuring lung mechanics in infants are needed for a better understanding of lung growth and function, and to study the effects of prenatal factors on subsequent lung growth in healthy infants. The forced oscillation technique requires minimal cooperation from the individual but has rarely been used in infants. The study aims to assess the use of the forced oscillation technique to measure the influence of antenatal exposures on respiratory mechanics in unsedated infants enrolled in a birth cohort study in Cape Town, South Africa. Methods: Healthy term infants were studied at 6–10 weeks of age using the forced oscillation technique. Respiratory impedance was measured in the frequency range 8–48 Hz via a face mask during natural sleep. Respiratory system resistance, compliance and inertance were calculated from the impedance spectra. Results: Of 177 infants tested, successful measurements were obtained in 164 (93%). Median (25–75%) values for resistance, compliance and inertance were 50.2 (39.5–60.6) cmH2O.s.L−1, 0.78 (0.61–0.99) mL.cmH2O−1 and 0.062 (0.050–0.086) cmH2O.s2.L−1, respectively. As a group, male infants had 16% higher resistance (P = 0.006) and 18% lower compliance (P = 0.02) than females. Infants whose mothers smoked during pregnancy had a 19% lower compliance than infants not exposed to tobacco smoke during pregnancy (P = 0.005). Neither maternal HIV infection nor ethnicity had a significant effect on respiratory mechanics. Conclusions: The forced oscillation technique is sensitive enough to demonstrate the effects of tobacco smoke exposure and sex in respiratory mechanics in healthy infants. This technique will facilitate assessing perinatal influences of lung function in infancy
The diverse nature of island isolation and its effect on land bridge insular faunas
Aim:
Isolation is a key factor in island biology. It is usually defined as the distance to the geographically nearest mainland, but many other definitions exist. We explored how testing different isolation indices affects the inference of impacts of isolation on faunal characteristics. We focused on land bridge islands and compared the relationships of many spatial and temporal (i.e., through time) isolation indices with community‐, population‐ and individual‐level characteristics (species richness, population density and body size, respectively).
Location:
Aegean Sea islands, Greece.
Time period:
Current.
Taxon:
Many animal taxa.
Methods:
We estimated 21 isolation indices for 205 islands and recorded species richness data for 15 taxa (invertebrates and vertebrates). We obtained body size data for seven lizard species and population density data for three. We explored how well indices predict each characteristic, in each taxon, by conducting a series of ordinary least squares regressions (controlling for island area when needed) and a meta‐analysis.
Results:
Isolation was significantly (and negatively) associated with species richness in 10 of 15 taxa. It was significantly (and positively) associated with body size in only one of seven species and was not associated with population density. The effect of isolation on species richness was much weaker than that of island area, regardless of the index tested. Spatial indices generally out‐performed temporal indices, and indices directly related to the mainland out‐performed those related mainly to neighbouring islands. No index was universally superior to others, including the distance to the geographically nearest mainland.
Main conclusions:
The choice of index can alter our perception of the impacts of isolation on biological patterns. The nearly automatic, ubiquitous use of distance to the geographically nearest mainland misrepresents the complexity of the effects of isolation. We recommend the simultaneous testing of several indices that represent different aspects of isolation, in order to produce more constructive and thorough investigations and avoid imprecise inference
Variable number of tandem repeats in clinical strains of Haemophilus influenzae
An algorithm capable of identifying short repeat motifs was developed and
used to screen the whole genome sequence available for Haemophilus
influenzae, since some of these repeats have been shown to affect
bacterial virulence. Various di- to hexanucleotide repeats were
identified, confirming and extending previous findings on the existence of
variable-number-of-tandem-repeat loci (VNTRs). Repeats with units of 7 or
8 nucleotides were not encountered. For all of the 3- to 6-nucleotide
repeats in the H. influenzae chromosome, PCR tests capable of detecting
allelic polymorphisms were designed. Fourteen of 18 of the potential VNTRs
were indeed highly polymorphic when different strains were screened. Two
of the potential VNTRs appeared to be short and homogeneous in length;
another one may be specific for the H. influenzae Rd strain only. One of
the primer sets generated fingerprint-type DNA banding patterns. The
various repeat types differed with respect to intrinsic stability as well.
It was noted for separate colonies derived from a single clinical specimen
or strains passaged for several weeks on chocolate agar plates that the
lengths of the VNTRs did not change. When several strains from different
patients infected during an outbreak of lung disease were analyzed,
increased but limited variation was encountered in al
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