Mean Annual Growth Rate Research Articles

Metformin Prescription Associated with Reduced Abdominal Aortic Aneurysm Growth Rate and Reduced Chemokine Expression in a Swedish Cohort

Recent reports suggest that the negative association between diabetes mellitus and abdominal aortic aneurysm (AAA) may be driven by metformin, the world's most common antidiabetic drug rather than diabetes per se. We sought to investigate the association among AAA growth rate, chemokine profile, and metformin prescription in a contemporary Swedish cohort. Patients under surveillance for small AAA were identified at 4 Swedish vascular centers with active AAA screening programs. Annual AAA growth rate, medical history, and prescribed medications were recorded for linear regression analysis. In a subset of patients with AAA and control subjects without AAA or diabetes, plasma samples were available and analyzed for 40 inflammatory chemokines. A total of 526 patients were included for AAA growth analysis: 428 without type 2 diabetes mellitus (T2DM), 65 with T2DM and metformin prescription, and 33 with T2DM but without metformin prescription. Patients were included from 2005 to 2017 with mean follow-up of 3.2 (1.7) years and median annual AAA growth rate 1.6mm, range -4.8 to 15.4mm. Mean (standard deviation) annual AAA growth rates were 2.3 (2.2) mm in non-T2DM patients versus 1.1 (1.1) mm in patients with T2DM with metformin prescription and 1.6 (1.4) mm among those with T2DM without metformin prescription. With non-T2DM patients as reference in an unadjusted and 2 adjusted models, metformin prescription was significantly associated with reduced AAA growth rate (P<0.001, P=0.005, and P=0.024, respectively), but not T2DM without metformin prescription (P=0.137, P=0.331, and P=0.479, respectively). Among 240 patients with AAA (152 without T2DM, 51 with T2DM and metformin, and 37 with T2DM without metformin) and 59 without AAA or T2DM, metformin prescription was associated with reduced expression of chemokines representing all classes of leukocytes. Metformin prescription is associated with reduced AAA growth rate, possibly mediated by broad anti-inflammatory effects. A randomized controlled trial is needed to determine what role metformin may play in AAA disease, particularly in the absence of T2DM.

Decomposing the drivers of residential space cooling energy consumption in EU-28 countries using a panel data approach

While space cooling currently represents less than 1% of final energy use in the residential sector of the European Union (EU-28), it was the fastest growing end-use during the 2000-15 period with a mean annual growth rate of 6% per year. Currently, little is known about factors which have driven regional air-conditioning (AC) energy consumption over time, since the literature is limited to cross-sectional studies that lack differentiation between climatic and non-climatic influences. Future projections for the EU's electricity sector may therefore neglect the potential implications of rapidly growing AC demand. We develop a novel decomposition framework, which breaks down residential space cooling energy consumption in EU-28 countries into the effect of different components from 2000 to 2015. Decomposition is extended to panel data models identifying specific drivers of space cooling's climate-sensitive components. Finally, we explore scenarios of residential AC energy consumption up to 2050 and evaluate their impact on summer time peak loads. AC diffusion was found to be the key driver of space cooling energy consumption, but this effect was partly counterbalanced by efficiency gains. While weather influences AC equipment ownership rate in EU-28 households, personal income has a larger marginal effect. In baseline scenarios, AC diffusion saturates by 2050, while modestly increasing sectoral final energy use. Still, our range of scenario values for space cooling energy consumption in 2050 exceed the majority of those originating from recently published projections. In a future renewables-driven electricity system, energy security risks may emerge from a scenario of fast AC up-take in new and renovated buildings, especially for colder European countries where modelled peak cooling electricity demand is shown to outgrow the projected expansion of solar capacity. These findings have important implications for the EU's strategy to decarbonise energy supply.

Characterizing the Key Predictors of Renewable Energy Penetration for Sustainable and Resilient Communities

AbstractWith a mean annual growth rate of roughly 50%, the solar industry has experienced unprecedented growth in the last decade, largely owing to the steadily falling prices of solar installation...

Ciliated Muconodular Papillary Tumor of the Lung: Thin-Section CT Findings of 16 Cases.

OBJECTIVE. The purpose of this article was to assess thin-section CT features of ciliated muconodular papillary tumors (CMPTs) of the lung and correlations between radiologic and pathologic findings. MATERIALS AND METHODS. Thin-section CT findings of 16 patients (10 men and six women; mean age, 70.7 years) with surgically resected CMPTs were retrospectively analyzed. Size, location, and internal characteristics of the tumors were evaluated. The amount of mucin in the tumors was assessed histopathologically and compared with CT findings. Tumor growth speed was calculated on the basis of size changes on thin-section CT. RESULTS. In all 16 patients, tumors were detected as a solitary pulmonary nodule. Thirteen tumors (81.3%) were located in the lower lobes, and 10 (62.5%) were adjacent to the pleura. Mean maximal diameter of the tumors was 9.1 mm (range, 6-14 mm). One tumor (6.3%) presented as a pure ground-glass nodule (GGN), seven (43.8%) as dense GGNs, and eight (50.0%) as solid nodules. Pathologically, the pure GGN and five of seven dense GGNs had a large amount of mucin, whereas seven of eight solid nodules had an intermediate or small amount of mucin. The mean annual tumor growth rate (in diameter) was 0.49 mm/y. CONCLUSION. CMPTs appear as solitary, small, and peripheral pulmonary nodules with very slow growth rates. CMPTs appearing as pure GGNs and dense GGNs tend to contain more mucin than CMPTs appearing as solid nodules.

Глобальные цепочки создания стоимости в электронной промышленности: региональные изменения после кризиса 2008 г.

The objective of the research is to identify the specifics of the global value chains (GVCs) in the world electronics industry after the 2008 global financial crisis. The paper analyses key indicators of GVC participation of the largest electronics exporters in three regions (Europe, North America, and Asia). The analysis is based on TiVA 2018. Major GVC tendencies after the 2008 global financial crisis are revealed. The key tendencies are strengthening the regional character of the exports in overall as well as origins of foreign value added in exports. After 2008 a decrease in mean annual export growth rates is seen. The countries increased the share of domestic value added content of gross exports before the crisis, while after the crisis they increased the domestic value added becoming accordingly less dependent on foreign exports. In most states the upward export participation index declined after the crisis. This trend indicates a post-crisis GVC reduction and the increased orientation of states to value added exports that are consumed by the target markets or higher added value components used by foreign states in their respective domestic finished products. The general tendencies for states in GVC electronics does not exclude customized approaches and specifics of their incorporation in value chains but the analysis leads to the conclusion that countries in the same region show similar patterns of GVC participation. The Asian region plays a key role in the post-crisis transformation of the value chains

Quality assessment of randomized controlled trials of Iranian traditional medicine: An eight-year study

IntroductionIranian traditional medicine (ITM) has a long history that dates back to a thousand years ago. In recent years, quantity of scientific productions in this field have significantly grown, but there are no reviews of randomized controlled trials (RCT) conducted in this field and their quality has not been assessed. In this review, we evaluated the quality of RCTs in ITM between 2010 and 2017. MethodsA systematic online search was done in national and international databases between 2010 and 2017. Inclusion criteria were: RCTs investigating some aspect/s of ITM. Nnon-randomized trial designs, animal experiments, reviews and meta-analyses, conference abstracts, short communications, editorials, letters and case reports or case series were excluded. Quality assessment of each RCT was conducted using the Consolidated Standards of Reporting Trials (CONSORT) checklist and Cochrane risk of bias tool. ResultsFrom 9568 records initially retrieved, only 151 RCTs remained eligible and were included in the study. The number of RCTs increased during 2010–2017, with a mean annual growth rate of 63 %. Based on the Cochrane Collaboration’s tool, most studies (51 %) were at moderate risk of bias. The mean (SD) CONSORT score for all items was 1.25(0.46, ranging from 0 to 2). Mean scores were low for some key items related to methodology. ConclusionDespite the significant increase in the number of RCTs conducted between 2010 and 2017 and some improvements in the quality of reporting, no improvement was observed in the trial methodology. Shortcomings in the methodology of trials can be overcome by further adherence to CONSORT statement.

Comparison of Continuous In-Situ CO2 Measurements with Co-Located Column-Averaged XCO2 TCCON/Satellite Observations and CarbonTracker Model Over the Zugspitze Region

Atmospheric CO2 measurements are important in understanding the global carbon cycle and in studying local sources and sinks. Ground and satellite-based measurements provide information on different temporal and spatial scales. However, the compatibility of such measurements at single sites is still underexplored, and the applicability of consistent data processing routines remains a challenge. In this study, we present an inter-comparison among representative surface and column-averaged CO2 records derived from continuous in-situ measurements, ground-based Fourier transform infrared measurements, satellite measurements, and modeled results over the Mount Zugspitze region of Germany. The mean annual growth rates agree well with around 2.2 ppm yr−1 over a 17-year period (2002–2018), while the mean seasonal amplitudes show distinct differences (surface: 11.7 ppm/column-averaged: 6.6 ppm) due to differing air masses. We were able to demonstrate that, by using consistent data processing routines with proper data retrieval and gap interpolation algorithms, the trend and seasonality can be well extracted from all measurement data sets.

Population Status of Green Turtles (Chelonia mydas) Foraging in Arica Bay, Chile1

Population characteristics and carapace growth rates were estimated for green turtles (Chelonia mydas) foraging in Arica Bay, northern Chile, from 2012 to 2016. Within the main foraging area of La Puntilla, an open population of up to 514 individuals was estimated by mark and recapture (Jolly-Seber method), with densities of 20–225 individuals/km2. Captured individuals (n = 159) ranged from 44.6 to 98.6 cm straight carapace length (SCL) with a mean SCL of 64.9 cm (SD 10.8); most turtles were juveniles; however, 10 were adults with SCL > 80 cm (three of these being males). A mean body condition index (BCI) of 1.64 (range 0.34–3.63) indicated healthy population conditions, with mean annual growth rates (AGR) of 4.6 cm/year (SD 2.97). The consistent presence of turtles between 2012 and 2016 and the relatively high abundance compared to the general situation reported for the species in Chile makes Arica Bay the most important feeding congregation of green turtles in the country. The population's healthy state and size, its location within an urban radius, and the multiple human uses of this site represent aspects that must be considered in protection and development plans for the city's coastal border.

Three-Dimensional Analysis of the Radiological Risk Factors for Progression of the Thoracic Ossification of the Posterior Longitudinal Ligament After Posterior Decompression and Stabilization

Although research shows that the ossified masses of ossification of the posterior longitudinal ligament (OPLL) continue to grow postoperatively, information regarding thoracic OPLL (T-OPLL) is lacking. To date, no study has investigated the progression of T-OPLL within each motion segment. The purpose of this study was to analyze the progression of T-OPLL in each motion segment using a 3-dimensional measurement and evaluate whether the type of T-OPLL and surgical methods affect its progression postoperatively. Clinical data from 20 patients (101 segments) with thoracic myelopathy secondary to OPLL were evaluated retrospectively. All patients underwent posterior decompression (laminectomy and stabilization or circumferential decompression [CD] and stabilization) at a single center. The 3-dimensional measurement of OPLL volume was performed using computed tomography scans. The ossified masses were classified into 2 types based on the fusion of each segment at the intervertebral space: type 1= complete bridging (fused); type 2= not fused. Statistical analyses were performed to determine the degree of T-OPLL progression according to the types and surgical methods. Mean OPLL progression was significantly higher in type 2. The mean annual growth rates of OPLL (AGRO) for groups 1 and 2 were 6.21% ± 6.11% per year and 23.50% ± 11.34% per year, respectively (P < 0.01). Further, no statistically significant differences were seen between the fixed and non-fixed groups (P= 0.23), and CD and non-CD segments (P= 0.56). The mean AGRO does not decrease even after stabilization and CD. Type 2 intervertebral space was a risk factor for T-OPLL progression. Cases of type 2 without CD need close follow-up.

Trends and Cost-Analysis of Lower Extremity Nerve Injury Using the National Inpatient Sample.

Peripheral nerve injuries (PNIs) of the lower extremities have been assessed in small cohort studies; however, the actual incidence, national trends, comorbidities, and cost of care in lower extremity PNI are not defined. Lack of sufficient data limits discussion on national policies, payors, and other aspects fundamental to the delivery of care in the US. To establish estimates of lower extremity PNIs incidence, associated diagnoses, and cost in the US using a comprehensive database with a minimum of a decade of data. The National Inpatient Sample was utilized to evaluate International Classification of Disease codes for specific lower extremity PNIs (9560-9568) between 2001 and 2013. Lower extremity PNIs occurred with a mean incidence of 13.3 cases per million population annually, which declined minimally from 2001 to 2013. The mean±SEM age was 41.6±0.1 yr; 61.1% of patients were males. Most were admitted via the emergency department (56.0%). PNIs occurred to the sciatic (16.6%), femoral (10.7%), tibial (6.0%), peroneal (33.4%), multiple nerves (1.3%), and other (32.0%). Associated diagnoses included lower extremity fracture (13.4%), complications of care (11.2%), open wounds (10.3%), crush injury (9.7%), and other (7.2%). Associated procedures included tibial fixation (23.3%), closure of skin (20.1%), debridement of open fractures (15.4%), fixation of other bones (13.5%), and wound debridement (14.5%). The mean annual unadjusted compounded growth rate of charges was 8.8%. The mean±SEM annual charge over the time period was $64 031.20±$421.10, which was associated with the number of procedure codes (β=0.2), length of stay (β=0.6), and year (β=0.1) in a multivariable analysis (P=.0001). These data describe associations in the treatment of lower extremity PNIs, which are important for considering national policies, costs, research and the delivery of care.

Growth Pattern and Prognostic Factors of Untreated Nonfunctioning Pituitary Adenomas.

ObjectivePituitary adenomas (PAs) are often detected as incidental findings. However, the natural history remains unclear. The objective of this study was to evaluate the natural history and growth pattern of untreated PAs. MethodsBetween 2003 and 2014, 59 PAs were managed with clinico-radiological follow up for longer than 12 months without any kind of therapeutic intervention. Tumor volumes were calculated at initial and last follow-up visit, and tumor growth during the observation period was determined. Data were analyzed according to clinical and imaging characteristics. ResultsThe mean initial and last tumor volume and diameter were 1.83±2.97 mL and 13.77±6.45 mm, 2.85±4.47 mL and 15.75±8.08 mm, respectively. The mean annual tumor growth rate was 0.33±0.68 mL/year during a mean observation period of 46.8±32.1 months. Sixteen (27%) PAs showed tumor growth. The initial tumor size (HR, 1.140; 95% confidence interval, 1.003–1.295; p=0.045) was the independent predictive factor that determined the tumor growth. Six patients (11%) of 56 conservatively managed non-symptomatic PAs underwent resection for aggravating visual symptoms with mean interval of 34.5 months from diagnosis. By Cox regression analysis, PAs of last longest diameter over 21.75 mm were a significant prognostic factor for eventual treatment. ConclusionThe initial tumor size of PAs was independently associated with the tumor growth. Six patients (11%) of conservatively managed PAs were likely to be treated eventually. PAs of last follow-up longest diameter over 21.75 mm were a significant prognostic factor for treatment. Further studies with a large series are required to determine treatment strategy.

A nowcasting model for Ecuador: Implementing a time-varying mean output growth

We propose a model to nowcast the annual growth rate of real GDP for Ecuador, whose economy lacks timely macroeconomic information for some key variables and has gone through unstable periods due to its dependence on oil exports. Our specification combines monthly information for 30 macroeconomic and financial variables with quarterly information for real GDP in a mixed-frequency approach. Our setup includes a time-varying coefficient on the mean annual growth rate of output to allow the model to incorporate prolonged periods of low or high growth. The model produces more accurate nowcasts of real output growth in pseudo out-of-sample exercises than a nowcasting model that assumes a constant mean real GDP growth rate. We also conduct sensitivity analyses on our nowcasting model within the time-varying mean setup and find that including financial variables can be detrimental to the performance of the proposed model.

On the diurnal, weekly, and seasonal cycles and annual trends in atmospheric CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; at Mount Zugspitze, Germany, during 1981–2016

Abstract. A continuous, 36-year measurement composite of atmospheric carbon dioxide (CO2) at three measurement locations on Mount Zugspitze, Germany, was studied. For a comprehensive site characterization of Mount Zugspitze, analyses of CO2 weekly periodicity and diurnal cycle were performed to provide evidence for local sources and sinks, showing clear weekday to weekend differences, with dominantly higher CO2 levels during the daytime on weekdays. A case study of atmospheric trace gases (CO and NO) and the passenger numbers to the summit indicate that CO2 sources close by did not result from tourist activities but instead obviously from anthropogenic pollution in the near vicinity. Such analysis of local effects is an indispensable requirement for selecting representative data at orographic complex measurement sites. The CO2 trend and seasonality were then analyzed by background data selection and decomposition of the long-term time series into trend and seasonal components. The mean CO2 annual growth rate over the 36-year period at Zugspitze is 1.8±0.4 ppm yr−1, which is in good agreement with Mauna Loa station and global means. The peak-to-trough amplitude of the mean CO2 seasonal cycle is 12.4±0.6 ppm at Mount Zugspitze (after data selection: 10.5±0.5 ppm), which is much lower than at nearby measurement sites at Mount Wank (15.9±1.5 ppm) and Schauinsland (15.9±1.0 ppm), but following a similar seasonal pattern.

Dendrochronology and dendroclimatology of Ceiba speciosa (A. St.-Hil.) Ravenna (Malvaceae) exposed to urban pollution in Rio de Janeiro city, Brazil

Nowadays, the biological monitoring through the growth rings has received increasing attention from ecologists and toxicologists. Structural analysis of these rings allows the incorporation of a time component in the study of plant responses to environmental variation. This allows also to evaluate long time series from the woody plants. In this paper, we assessed the dendrochronological characteristics of Ceiba speciosa growing in forest environment and under urbanization impact. Stem samples were obtained with Pressler probe into trees growing the campus of the Oswaldo Cruz Foundation, adjacent to one of the main urban thoroughfares of the city of Rio de Janeiro (Avenida Brasil), and at Tinguá Biological Reserve, an important remnant of Atlantic Forest. The samples were processed and analyzed following usual dendrochronological methods, with COFECHA and ARSTAN softwares. A negative exponential curve was used for standardization of the series. The residual chronologies were correlated with precipitation and temperature indexes obtained from NOAA weather database. Growth rings are distinct and annual, marked by bands of marginal parenchyma, thick-walled and radially flattened fibres in latewood and distended rays in earlywood. In both sites, the intercorrelation between the trees was above 0.40. Ages ranged from 11 to 41 years in the urban site and from 27 to 64 years in the forest site. In urban area, mean annual increment and cumulative average growth rates were 6 mm/year and 142.62 mm, respectively. At the forest site, these rates were 4 mm/year and 173.07 mm, respectively. The comparison between cumulative radial increment of the two sites revealed that trees of the urban site had higher increment rates beginning at the start of their development and consequently, they showed similar diameters despite lower ages. Correlation analysis between the chronologies and climatic factors revealed a positive association between growth and hot and rainy periods for both study sites. However, there is an immediate response of urban trees in relation to the rains and, a late response of forest trees to the same factor. The dry and hot climate, typical of urban environments, and the absence of natural water reserves in urban soil, may explain this more immediate response of urban tree growth to rainfall and temperature indexes. Our results revealed that Ceiba speciosa is a plastic and stress-tolerant species that is able to survive and adapt to polluted urban conditions. These features, along with its wide natural distribution and frequent planting for city landscaping, make this species an important biomarker for environmental monitoring studies.

Study on direction of Indian automobile industry

In this research paper researcher has presented and analysed the directions of Indian Automobile Industry. It is very important to understand to which country Indian Automobile Industry is exporting and quantity of exporting. Because the Indian Automobile Industry held the fifth position in the world and the third position in the Asian Automobile Industry. For analysing the export performance of Indian automobile Industry, the researcher has used the tools like mean, standard deviation, co-efficient variance and compound annual growth rate for ten years from 2008–09 to 2017–18.

Mark–Recapture Validation of Pectoral Fin Ray Age Estimation for Lake Sturgeon

AbstractAge estimation is an integral part of fisheries management and is critical for evaluations of growth, mortality, and recruitment. Validation of ages obtained from age estimation of hard parts is a necessary part of the aging process because understanding the magnitude of error and bias associated with structure interpretation provides context for managers using the data. However, validation studies on large‐bodied and long‐lived species, such as Lake Sturgeon Acipenser fulvescens, are challenging. We utilized a 20‐year mark–recapture dataset from Lake St. Clair and the St. Clair River, Michigan, to validate pectoral fin ray age estimates from 51 individuals that were sampled twice, with 2 to 17 years between capture–recapture events. Samples were divided into four quartiles based on mean annual growth rates during their time at large (mean growth for quartiles = 0.6 cm/year, 2.1 cm/year, 3.7 cm/year, and 5.1 cm/year). Age error was defined as the difference between the estimated age of the fish at first and second capture and the number of years at large. No difference in time at large existed among the four groups, but age error differed among the four groups. Additionally, age error did not differ from zero for the two fastest‐growing quartiles but did differ significantly from zero for the two slowest‐growing quartiles. We conclude that for Lake Sturgeon growing faster than 3 cm/year (generally less than 100 cm TL) pectoral fin rays provide valid age estimates. Managers should evaluate the growth rates of Lake Sturgeon in their populations to determine a size threshold for using fin rays for age determination.

Uncertainties of potentials and recent changes in global yields of major crops resulting from census- and satellite-based yield datasets at multiple resolutions.

Global agriculture is under pressure to meet increasing demand for food and agricultural products. There are several global assessments of crop yields, but we know little about the uncertainties of their key findings, as the assessments are driven by the single best yield dataset available when each assessment was conducted. Recently, two different spatially explicit, global, historical yield datasets, one based on agricultural census and the other largely based on satellite remote sensing, became available. Using these datasets, we compare the similarities and differences in global yield gaps, trend patterns, growth rates and changes in year-to-year variability. We analyzed maize, rice, wheat and soybean for the period of 1981 to 2008 at four resolutions (0.083°, 0.5°, 1.0° and 2.0°). Although estimates varied by dataset and resolution, the global mean annual growth rates of 1.7–1.8%, 1.5–1.7%, 1.1–1.3% and 1.4–1.6% for maize, rice, wheat and soybean, respectively, are not on track to double crop production by 2050. Potential production increases that can be attributed to closing yield gaps estimated from the satellite-based dataset are almost twice those estimated from the census-based dataset. Detected yield variability changes in rice and wheat are sensitive to the choice of dataset and resolution, but they are relatively robust for maize and soybean. Estimates of yield gaps and variability changes are more uncertain than those of yield trend patterns and growth rates. These tendencies are consistent across crops. Efforts to reduce uncertainties are required to gain a better understanding of historical change and crop production potential to better inform agricultural policies and investments.

Emixustat Hydrochloride for Geographic Atrophy Secondary to Age-Related Macular Degeneration: A Randomized Clinical Trial

To determine whether emixustat hydrochloride (emixustat) reduces the rate of enlargement of geographic atrophy (GA) compared with placebo in subjects with age-related macular degeneration (AMD) and to evaluate the safety and tolerability of emixustat over 24 months of treatment. Multicenter, randomized, double-masked, placebo-controlled, phase 2b/3 clinical trial. Patients with GA secondary to AMD, a visual acuity score of at least 35 letters, and GA with a total area of 1.25 to 18 mm2 were enrolled. Subjects were randomized (1:1:1:1) to emixustat 2.5 mg, 5 mg, 10 mg, or placebo, administered orally once daily for 24 months. Visits included screening, baseline, and months 1, 2, 3, 6, 9, 12, 15, 18, 21, 24, and25. The primary efficacy end point was the mean annual growth rate of total GA area in the study eye, as measured by a central reading center using fundus autofluorescence (FAF) images. The change from baseline in normal luminance best-corrected visual acuity (NL-BCVA) was a secondary efficacy end point. Of 508 randomized subjects, 320 completed the study. Demographics and baseline characteristics were comparable between treatment groups. On average, GA lesions in the study eye grew at a similar rate in each group (emixustat: 1.69 to 1.84 mm2/year; placebo: 1.69 mm2/year; P ≥ 0.81). Changes in NL-BCVA were also comparable between groups. Subjects with a larger low luminance deficit (LLD) at baseline (≥20 letters) demonstrated a more rapid growth of GA over 24 months. No relationship was observed between the risk-allele status of the AMD-associated single-nucleotide polymorphisms tested and the growth rate of GA. The most common adverse events in emixustat-treated subjects were delayed dark adaptation (55%), chromatopsia (18%), visual impairment (15%), and erythropsia (15%). Emixustat did not reduce the growth rate of GA in AMD. The most common adverse events were ocular in nature and likely related to the drug's mechanism of action. Data gained from this study over a 2-year period add to the understanding of the natural history of GA and the baseline characteristics affecting the growth rate of GA.

Growth, Survival, and Mortality of Juvenile and Adult Alien Conrad's False MusselMytilopsis leucophaeata(Conrad, 1831) (Mollusca, Bivalvia, Dreissenidae) in a Brackish Canal

The false mussel, Mytilopsis leucophaeata originating from the Atlantic coast and Gulf of Mexico in North America invaded brackish water systems in Europe. Seasonal sessile population structure is determined by spat fall, growth, and mortality. Juvenile and adult M. leucophaeata were kept in cages in a brackish water canal to study their mortality and to estimate annual and seasonal shell growth rate in relation to shell size and water temperature. Mortality increased with increasing temperature with the strongest effect on the 4–6 mm and 8–10 mm size classes. The average mortality of all size classes of M. leucophaeata in cage experiments was lowest in winter, increased from April to July, and peaked in July and August. Between a water temperature of 18 and 23°C, a strong growth was observed for mussels of size classes 2–14 mm, whereas mussels of size class 14–16 mm showed only a slight growth (<20 µm day-1) and size classes 16–18 mm and 18–22 mm showed no growth at all. When water temperature was between 9 and 18°C, there was no or slight growth, and at lower than 9°C, hardly any growth. Especially for the small mussels, the influence of the water temperature on shell growth is strong. Polynomial regression showed a mean summer growth rate of 94 µm day-1 for the 2–4 mm class, 37 µm day-1 for the 10–12 mm class, and no growth for the 18–22mmclass. Analysis of all available (literature) data yielded mean summer and annual growth rates of M. leucophaeata collected in brackish western European harbors and canals ranging from 30 to 133 µm day-1 and 8 to 49 µm day-1, respectively. Increase of water temperature by climate change or thermal discharges will increase growth rates and mortality of this mussel.

Age, Growth, and Sexual Maturity of the Channeled WhelkBusycotypus canaliculatus(Linnaeus, 1758) and Knobbed WhelkBusycon carica(Gmelin, 1791) in Narragansett Bay, Rhode Island

A total of 840 channeled (female, n = 388; male, n = 452) and 405 knobbed (female, n = 239; male, n = 166) whelks were measured for shell length (SL) and shell width (SW), with age estimates made from corresponding operculum annual growth striae readings. Gonads (ovary and testis) and reproductive structures [nidamental gland (females) and vas deferens (males)] were assessed macroscopically for maturity stage. All whelks used in this study were collected from Rhode Island state waters within Narragansett Bay, Mount Hope Bay, and Little Narragansett Bay (Pawcatuck River). Data were aggregated by species and sex, with each species treated as a single population within the study area. Age at size (growth rates) and age and size at 50% and 95% maturity were estimated for both species by sex. Female channeled whelk had the highest mean annual growth rates and reached minimum legal size quickest [minimum shell length (MSL) = 136.53 mm, minimum shell width (MSW) = 76.20 mm] and at the youngest age. Male channeled and female knobbed had similar growth rates and were the next quickest to reach MSL and MSW. Male knobbed grew slowest and were the last to enter the fishery and at the oldest age. Estimated age at 50% maturity (A50) for female channeled and female knobbed was nearly the same at 8.46 and 8.35 y, respectively. Male channeled had an estimated A50 of 7.35 y and that of male knobbed was 5.65 y. Estimated size at 50% maturity (SL50 and SW50) for female channeled was 136.8 mm SL and 77.5 mm SW; female knobbed was 124.0 mm SL and 68.4 mm SW; male channeled was 116.0 mm SL and 64.9 mm SW; and male knobbed was 89.4 mm SL and 47.7 mm SW. No instances of protandrous hermaphroditism, pseudohermaphroditism, or imposex were observed. A total of 231 newly hatched (age 0) knobbed whelks were measured for SL and SW, with mean SL and SW at age 0 included in age-at-size (growth rate) analyses.