Mangrove growth response to experimental warming is greatest near the range limit in northeast Florida.

Shrubs are invading into grasslands around the world, but we don't yet know how these shrubs will fare in a warmer future. In ecotonal coastal wetland ecosystems, woody mangroves are encroaching into herbaceous salt marshes owing to changes in temperature, precipitation, and sediment dynamics. Increasing mangrove biomass in wetlands often increases carbon storage, which is high in these productive ecosystems, but little is known about how mangrove growth will change in response to warming. To address this knowledge gap, we deployed warming experiments at three coastal wetland sites along a latitudinal gradient in northeast Florida where Avicennia germinans, black mangroves, are encroaching into salt marshes. We achieved air temperature warming (+1.6°C during the day) at all three sites and measured stem elongation, canopy height and area changes, and leaf and node number. After 2 yr of warming, we found that mangrove growth rate in height increased due to warming. Warming increased stem elongation by 130% over unwarmed control plots after 1 yr at the northern site. Mangrove growth in canopy area did not respond to warming. Site differences in growth rate were pronounced, and mangrove growth in both height and area were lowest at the northern site, despite greater impacts of warming at that site. We also found that area-based relative growth rate was five times higher across all treatments than height-based relative growth rate, indicating that mangroves are growing wider rather than taller in these ecotonal environments. Our findings indicate that the growth effect of experimental warming depends on site characteristics and growth parameter measured. We also propose that differential mangrove growth across the three sites may be driven by biotic factors such as the identity of the salt marsh species into which mangroves are encroaching. Our results suggest that, as seen in other ecosystems, wetland plants may respond most strongly to warming at their poleward range edge.

External validation of the ProCaRS nomograms and comparison of existing risk-stratification tools for localized prostate cancer.

INTRODUCTION: The purpose of this study was to perform a direct comparison of several existing risk-stratification tools for localized prostate cancer in terms of their ability to predict for biochemical failure-free survival (BFFS). Two large databases were used and an external validation of two recently developed nomograms on an independent cohort was also performed in this analysis. METHODS: Patients who were treated with external beam radiotherapy (EBRT) and/or brachytherapy for localized prostate cancer were selected from the multi-institutional Genitourinary Radiation Oncologists of Canada (GUROC) Prostate Cancer Risk Stratification (ProCaRS) database (n=7974) and the Centre Hospitalier de l'Université de Montréal (CHUM) validation database (n=2266). The primary outcome was BFFS using the Phoenix definition. Concordance index (C-index) reported from Cox proportional hazards regression using 10-fold cross validation and decision curve analysis (DCA) were used to predict BFFS. RESULTS: C-index identified Cancer of the Prostate Risk Assessment (CAPRA) score and ProCaRS as superior to the historical GUROC and National Comprehensive Cancer Network (NCCN) risk-stratification systems. CAPRA modeled as five and three categories were superior to GUROC and NCCN only for the CHUM database. C-indices for CAPRA score, ProCaRS, GUROC, and NCCN were 0.72, 0.72, 0.71, and 0.72, respectively, for the ProCaRS database, and 0.66, 0.63, 0.57, and 0.60, respectively, for the CHUM database. However, many of these comparisons did not demonstrate a clinically meaningful difference. DCA identified minimal differences across the different risk-stratification systems, with no system emerging with optimal net benefit. External validation of the ProCaRS nomograms yielded favourable calibrations of R2=0.778 (low-dose rate [LDR]-brachytherapy) and R2=0.868 (EBRT). CONCLUSIONS: This study externally validated two ProCaRS nomograms for BFFS that may help clinicians in treatment selection and outcome prediction. A direct comparison between existing risk-stratification tools demonstrated minimal clinically significant differences in discriminative ability between the systems, favouring the CAPRA and ProCaRS systems. The incorporation of novel prognostic variables, such as genomic markers, is needed.

Brachytherapy improves biochemical failure-free survival in low- and intermediate-risk prostate cancer compared with conventionally fractionated external beam radiation therapy: a propensity score matched analysis.

PURPOSE: To compare, in a retrospective study, biochemical failure-free survival (bFFS) and overall survival (OS) in low-risk and intermediate-risk prostate cancer patients who received brachytherapy (BT) (either low-dose-rate brachytherapy [LDR-BT] or high-dose-rate brachytherapy with external beam radiation therapy [HDR-BT+EBRT]) versus external beam radiation therapy (EBRT) alone. METHODS AND MATERIALS: Patient data were obtained from the ProCaRS database, which contains 7974 prostate cancer patients treated with primary radiation therapy at four Canadian cancer institutions from 1994 to 2010. Propensity score matching was used to obtain the following 3 matched cohorts with balanced baseline prognostic factors: (1) low-risk LDR-BT versus EBRT; (2) intermediate-risk LDR-BT versus EBRT; and (3) intermediate-risk HDR-BT+EBRT versus EBRT. Kaplan-Meier survival analysis was performed to compare differences in bFFS (primary endpoint) and OS in the 3 matched groups. RESULTS: Propensity score matching created acceptable balance in the baseline prognostic factors in all matches. Final matches included 2 1:1 matches in the intermediate-risk cohorts, LDR-BT versus EBRT (total n=254) and HDR-BT+EBRT versus EBRT (total n=388), and one 4:1 match in the low-risk cohort (LDR-BT:EBRT, total n=400). Median follow-up ranged from 2.7 to 7.3 years for the 3 matched cohorts. Kaplan-Meier survival analysis showed that all BT treatment options were associated with statistically significant improvements in bFFS when compared with EBRT in all cohorts (intermediate-risk EBRT vs LDR-BT hazard ratio [HR] 4.58, P=.001; intermediate-risk EBRT vs HDR-BT+EBRT HR 2.08, P=.007; low-risk EBRT vs LDR-BT HR 2.90, P=.004). No significant difference in OS was found in all comparisons (intermediate-risk EBRT vs LDR-BT HR 1.27, P=.687; intermediate-risk EBRT vs HDR-BT+EBRT HR 1.55, P=.470; low-risk LDR-BT vs EBRT HR 1.41, P=.500). CONCLUSIONS: Propensity score matched analysis showed that BT options led to statistically significant improvements in bFFS in low- and intermediate-risk prostate cancer patient populations.

The prostate cancer risk stratification project: database construction and risk stratification outcome analysis.

This investigation reports on the biochemical and clinical outcomes of a newly created pan-Canadian Prostate Cancer Risk Stratification (ProCaRS) database developed by the Genitourinary Radiation Oncologists of Canada (GUROC). GUROC ProCaRS template-compliant data on 7974 patients who underwent radiotherapy were received from 7 unique databases. Descriptive analysis, Cox proportional hazards, and Kaplan-Meier analyses were performed using American Society for Radiation Oncology (ASTRO) biochemical failure-free survival (BFFS), prostate cancer-specific survival, and overall survival. Multivariable modeling for the primary ASTRO BFFS end point showed that age, prostate-specific antigen, T stage, and Gleason score and components such as hormonal therapy, and radiation treatment (brachytherapy with better outcome than external-beam) were predictive of outcome. Kaplan-Meier analysis of the existing GUROC and new NCCN classification system both showed good separation of all clinical outcome curves. The construction of a pan-Canadian database has informed important prostate cancer radiotherapy outcomes and risk stratification.

The prostate cancer risk stratification (ProCaRS) project: recursive partitioning risk stratification analysis.

BACKGROUND: The Genitourinary Radiation Oncologists of Canada (GUROC) published a three-group risk stratification (RS) system to assist prostate cancer decision-making in 2001. The objective of this project is to use the ProCaRS database to statistically model the predictive accuracy and clinical utility of a proposed new multi-group RS schema. METHODS: The RS analyses utilized the ProCaRS database that consists of 7974 patients from four Canadian institutions. Recursive partitioning analysis (RPA) was utilized to explore the sub-stratification of groups defined by the existing three-group GUROC scheme. 10-fold cross-validated C-indices and the Net Reclassification Index were both used to assess multivariable models and compare the predictive accuracy of existing and proposed RS systems, respectively. RESULTS: The recursive partitioning analysis has suggested that the existing GUROC classification system could be altered to accommodate as many as six separate and statistical unique groups based on differences in BFFS (C-index 0.67 and AUC 0.70). GUROC low-risk patients would be divided into new favorable-low and low-risk groups based on PSA ⩽6 and PSA >6. GUROC intermediate-risk patients can be subclassified into low-intermediate and high-intermediate groups. GUROC high-intermediate-risk is defined as existing GUROC intermediate-risk with PSA >=10 AND either T2b/c disease or T1T2a disease with Gleason 7. GUROC high-risk patients would be subclassified into an additional extreme-risk group (GUROC high-risk AND (positive cores ⩾87.5% OR PSA >30). CONCLUSIONS: Proposed RS subcategories have been identified by a RPA of the ProCaRS database.

Sap flow response of Eucaylyptus (Eucalyptus urophylla) to environmental stress in South China.

Sap flow and environmental conditions were monitored at two Eucalyptus (Eucalyptus urophylla S.T.Blake) plantations at Hetou and Jijia, located in Leizhou, Zhanjiang, Guangdong Province. It was found that daily sap flux density (SFD) of Eucalyptus was closely related to daily atmospheric vapor pressure deficit (VPD) (R2 = 0.76, P = 0.01 at Hetou and R2 = 0.7021, P = 0.01 at Jijia) at both sites. No significant relationship existed between daily SFD and mean daily air temperature at both sites. Daily SFD varied with wind speed Y = -17585X3 + 15147X2 - 1250.7X + 2278.4 (R2 = 0.68; P = 0.01) at Hetou and Y = -101.67X3 - 1.65X2 - 376.4X + 1914.8 (R2 = 0.40, P = 0.05) at Jijia, where Y was daily SFD, X was daily wind speed. Experimental observations yielded the following data: (1) the critical lower and upper daily VPD threshold were 0 and 2 kPa, within which daily SFD varied from 540+/-70 L/(m2.d) to 4739+/-115 L/(m2.d) at Hetou site, from 397+/-26 L/(m2.d) to 3414+/-191 L/(m2.d) at Jijia site; (2) Diurnal SFDs at Hetou site were much higher under low relative humidity (< 30%) and slightly lower under high relative humidity (> 80%) compared with those at the Jijia site; (3) The upper and lower threshold of daily and diurnal RAD for the optimal water use of E. urophylla plantations were 18+/-2.7 and 2+/-1 MJ/(m2.d), 669 and 0 J/(cm2.h) during the observation period.

Water use by fast-growing Eucalyptus urophylla plantations in southern China.

Tree growth, water use, climate and soil water conditions were monitored over 12 months in two 3-4-year-old Eucalyptus urophylla S.T. Blake plantations on the Leizhou Peninsula of southern China. The Hetou plantation was established on a sandy soil of sedimentary origin with low water storage capacity, and the Jijia plantation was established on a clay soil formed on basalt. Sapwood area was approximately 50% higher at Jijia than at Hetou because of differences in plant spacing (1994 versus 1356 stems ha(-1)). Annual water use, assessed by heat pulse measurements, was 542 mm at Hetou and 559 mm at Jijia, with mean sap flux densities of 2772 and 1839 l m(-2) day(-1), respectively. Limitations to water use, imposed by climatic and soil factors, were quantified by analysis of daily canopy conductance in relation to daytime vapor pressure deficit (VPD) and soil water content. Similar annual water use at the two sites was a result of higher VPD and soil water availability at Hetou compensating for the greater sapwood area at Jijia. Potential annual water use in the absence of soil water limitation was estimated at 916 mm at Jijia and 815 mm at Hetou. Higher water availability during the dry season and early wet season at Hetou than at Jijia was the result of deep root systems. The results imply that water use by plantations on soils with high water availability and in areas of high VPD may be reduced by establishment at wider spacing. The environmental cost of water use by plantations must be weighed against their economic and environmental values to determine an appropriate mix of forestry, agriculture and other land uses in regions where water resources are limited.

St. Louis encephalitis outbreak in Louisiana in 2001.

A description of the St. Louis encephalitis (SLE) outbreak in Northeast Louisiana is presented. In the fall of 2001 there were 63 cases of St. Louis encephalitis in Monroe and West Monroe and seven additional cases in the neighboring parishes of Richland, Morehouse and Franklin. All cases had a clinical presentation of encephalitis and were confirmed serologically. Clinically most cases presented with fever, meningitis syndrome with altered mental status. Tremors were common (56% of cases). There were three deaths. Age-group distribution showed a predominance among 45 and older. The epidemic curve based on diagnosis date showed an explosive outbreak starting August 8, 2001, reaching a peak by the second week, and progressively slowing down. The curve showed that by the time the first case was diagnosed, 60% or more of the cases were already infected. Most of the cases come from low socio-economic areas. Houses were often run down, many with screens in disrepair. Backyards were usually large, with heavy brush and many trees. There was an abundance of sources of mosquito larvae, particularly for Culex quinquefasciatus which is the main vector. Mosquito pools confirmed the presence of SLE virus. As soon as the first case was reported, a campaign of health education and increased mosquito adulticiding were implemented.

Transpiration and canopy conductance in a eucalypt plantation using shallow saline groundwater.

Tree water use and canopy conductance were monitored in a 20-year-old Eucalyptus grandis W. Hill ex Maiden and Eucalyptus camaldulensis Dehnh. plantation shown to be using shallow saline groundwater. Annual water use, obtained from two years of heat pulse measurements of daily water use, was approximately 300 mm for both species with a winter minimum and a weak maximum in spring. Canopy conductance obtained from the ratio of daily water use to daily mean vapor pressure deficit (VPD) was low during summer, but rose to high values in winter. Diurnal variation in stomatal conductance was recorded in late summer and spring. Stomatal conductance increased with radiation but showed no evidence of a relationship with VPD. Canopy conductance was generally less than half the observed stomatal conductance on a leaf area basis, and usually declined steadily through the day, showing a strong inverse relationship with VPD. For both species, a decoupling coefficient (Omega) of 0.1 to 0.3 was obtained from canopy conductance and climate observations, and a higher value of Omega was derived from canopy and stomatal conductances. The difference in Omega values is interpreted as demonstrating the inclusion of a soil to leaf conductance within the canopy conductance estimates. Soil to leaf conductance is smaller than both stomatal and aerodynamic conductances, and effectively limits water use by the plantation. The observed variation in soil to leaf conductance is consistent with resistance to water movement to the roots increasing as the soil in the vicinity of the active roots dries as a result of water uptake during the day. Plantations may be useful for transpiring shallow ground-water to control rising water tables and salinity, but their effectiveness as water users will be reduced as the water table is drawn down in soils of low hydraulic conductivity. Plantations irrigated with pumped groundwater or drainage water may provide a more efficient disposal system where these water sources are available.