Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 5 de 5
Filter
Add more filters










Database
Language
Publication year range
1.
HIV Med ; 8(1): 28-31, 2007 Jan.
Article in English | MEDLINE | ID: mdl-17305929

ABSTRACT

BACKGROUND: Standard two-step HIV testing is limited by poor return-for-results rates and misses high-risk individuals who do not access conventional testing facilities. METHODS: We describe a community-based rapid HIV testing programme in which homeless and marginally housed adults recruited from shelters, free meal programmes and single room occupancy hotels in San Francisco received OraQuick Rapid HIV-1 Antibody testing (OraSure Technologies, Bethlehem, PA, USA). RESULTS: Over 8 months, 1614 adults were invited to participate and 1213 (75.2%) underwent testing. HIV seroprevalence was 15.4% (187 of 1213 individuals) overall and 3.5% (37 of 1063) amongst high-risk individuals reporting no previous testing, a prior negative test, or previous testing without result disclosure. All 1213 participants received their results. Of 30 newly diagnosed persons who received confirmatory results, 26 (86.7%) reported at least one contact with a primary healthcare provider in the 6 months following diagnosis. CONCLUSIONS: We conclude that community-based rapid testing is feasible, acceptable and effective based on the numbers of high-risk persons tested over a short period, the participation rate, the prevalence of new infection, the rate of result disclosure, and the proportion linked to care.


Subject(s)
HIV Infections , HIV Seroprevalence , Mass Screening/methods , Adolescent , Adult , Community Health Services , Female , HIV Infections/diagnosis , HIV Infections/epidemiology , Health Services Accessibility , Ill-Housed Persons , Humans , Male , Middle Aged , Residence Characteristics , San Francisco/epidemiology , Urban Health , Urban Health Services
2.
Tree Physiol ; 22(9): 613-23, 2002 Jun.
Article in English | MEDLINE | ID: mdl-12069917

ABSTRACT

To determine the relationship between phloem transport and changes in phloem water content, we measured temporal and spatial variations in water content and sucrose, glucose and fructose concentrations in phloem samples and phloem exudates of 70- and 30-year-old Norway spruce trees (Picea abies (L.) Karst.). Large temporal and spatial variations in phloem water content (1.4-2.6 mg mg(dw)(-1)) and phloem total sugar concentration (31-70 mg g(dw)(-1)) paralleled each other (r(2) = 0.83, P < 0.0001 for the temporal profile and r(2) = 0.96, P < 0.008 for the spatial profile), indicating that phloem water content depends on the total amount of sugar to be transferred. Changes in phloem water content were unrelated to changes in bark thickness. Maximum changes in phloem water content calculated from dendrometer readings were only 8-11% of the maximum measured changes in phloem water content, indicating that reversible changes in bark thickness did not reflect changes in internal water relations. We also studied the relationship between xylem sap velocity and changes in bark thickness in 70-year-old trees during summer 1999 and winter 1999-2000. Sap flow occurred sporadically throughout the winter, but there was no relationship between bark shrinkage or swelling and sap velocity. In winter, mean daily xylem sap velocity was significantly correlated with mean daily vapor pressure deficit and air temperature (P < 0.0001, in both cases). Changes in bark thickness corresponded with both short- and long-term changes in relative humidity, in both winter and summer. Under controlled conditions at > 0 degrees C, changes in relative humidity alone caused changes in thickness of boiled bark samples. Because living bark of Norway spruce trees contains large areas with crushed and dead sieve cell zones-up to 24% of the bark is air-filled space-we suggest that this space can compensate for volume changes in living phloem cells independently of total tissue water content. We conclude that changes in bark thickness are not indicative of changes in either phloem water capacitance or xylem sap flow.


Subject(s)
Picea/physiology , Plant Bark/physiology , Trees/physiology , Extracellular Space/physiology , Fructose/analysis , Glucose/analysis , Picea/chemistry , Plant Bark/anatomy & histology , Plant Bark/chemistry , Plant Stems/chemistry , Plant Stems/physiology , Plant Transpiration/physiology , Seasons , Sucrose/analysis , Trees/chemistry , Water/analysis , Water/physiology
3.
Environ Pollut ; 109(3): 473-8, 2000 Sep.
Article in English | MEDLINE | ID: mdl-15092880

ABSTRACT

Current-year seedlings of beech, ash, Norway spruce and Scots pine were exposed during one growing season to different, but moderate, ozone (O(3)) scenarios representative for Switzerland (50, 85, 100% ambient, 50% ambient+30 nl l(-1)) in open-top chambers (OTCs) and to ambient O(3) concentrations in the field. Biomass significantly decreased with increasing O(3) dose in all species except for spruce. Losses of 25.5% (ash), 17.4% (beech), 9.9% (Scots pine) were found per 10 microl l(-1) h accumulated O(3) exposure over a threshold concentration of 40 nl l(-1) during daylight hours (AOT40). Ratios of root/shoot biomass (RSR) also significantly decreased with increasing AOT40 levels in beech and ash, but not in Norway spruce and Scots pine. The data show that the deciduous species beech and ash were more susceptible to O(3) with respect to RSR and biomass than the coniferous species Norway spruce and Scots pine.

4.
Environ Pollut ; 109(3): 501-7, 2000 Sep.
Article in English | MEDLINE | ID: mdl-15092883

ABSTRACT

This paper describes a relationship between ozone exposure, biomass, visual symptoms and a chlorophyll a fluorescence performance index for young beech trees (Fagus sylvatica). The plants were exposed to four levels of ozone in open-top fumigation chambers (50, 85, 100% of ambient, and 50% of ambient+30 nl l(-1) ozone) that fluctuated in parallel with ambient ozone during a single growing season. The trees were fumigated in the four treatments with ozone levels corresponding to an AOT40 (accumulated exposure above a threshold of 40 nl l(-1)) of 0.01, 3.35, 7.06 and 19.70 microl l(-1) h, respectively. Highly significant differences were found between the 50% of ambient+30 nl l(-1) ozone treatment and all other treatments, with a 70.5% reduction in primary photosynthetic performance, as measured with the PI index. The reduction of the PI values demonstrated a high correlation with visual symptom development (r(2)=0.98), and by the end of September with biomass loss (r(2)=0.99). A significant ozone exposure-response relationship was found between AOT40 and primary photochemistry (r(2)=0.97). Thus, analysis of PI provides an alternative method for regional monitoring of tree health within the context of the currently employed AOT40.

5.
Environ Pollut ; 56(2): 155-67, 1989.
Article in English | MEDLINE | ID: mdl-15092485

ABSTRACT

This study centres around the question of how far the analysis of spruce needles (Picea abies L.) provides a suitable tool for detecting and describing large-scale air pollution, primarily by heavy metals, in Switzerland. For that reason 1637 spruce shoots from 833 sites were analysed, relationships between the different elements were calculated and maps of their spatial distribution drawn. The results show that needle analysis is a valid instrument for the identification of various air pollutants in Switzerland. The element best suited is Pb, followed by some others like Mo, Fe, Cd or S. The most heavily polluted areas in Switzerland are the midlands, and in the north and north-west. Their spatial distribution suggests that in these areas the indicator elements are derived from local sources.

SELECTION OF CITATIONS
SEARCH DETAIL
...