Relation between periodontal disease and arterial stiffness.

BACKGROUND AND OBJECTIVE: Periodontal disease has been described as playing a role in the atherosclerosis process, and its relation with intimal thickness and vascular endothelial function (EF) has been investigated. The present study sought to determine whether there are differences in parameters of arterial stiffness and EF between patients with and without severe periodontal disease (SPD). MATERIAL AND METHODS: Patients referred to the School of Dentistry University of Buenos Aires, were assessed. Demographic characteristics, atherogenic risk factors and concomitant pathologies were recorded. Patients with known cardiovascular pathology were excluded. Using carotid Doppler ultrasound an operator assessed arterial stiffness parameters: compliance, elastic modulus (EM), ß stiffness index (ßSI) and vascular EF by brachial artery flow-mediated dilatation. The patients were divided into two groups: with and without SPD. RESULTS: Forty patients were included; 60% were women; 15 were in the SPD group and 25 in the group without SPD. Respective results of the studied variables were: age 56.53 ± 17.58 vs. 51.12 ± 12.97 years (NS); probing depth 2.53 ± 1.30 (95% CI 1.81-3.25) vs. 1.25 ± 0.51 (95% CI 1.31-1.73) p = 0.02; clinical attachment level 4.80 ± 2.00 (95% CI 3.69-5.91) vs. 1.72 ± 0.93 (95% CI 1.33-2.11) p = 0.001; intimal thickness 0.10 ± 0.17 (95% CI 0.095-0.11) vs. 0.82 ± 0.18 (95% CI 0.074-0.98) (NS); EM 48.33 ± 12.53 vs. 38.86 ± 7.69 (p = 0.005); ßSI 4.21 ± 1.03 vs. 3.64 ± 1.02 (p = 0.004); EF 16.13 ± 5.02 vs. 22.76 ± 4.50 (p = 0.0003). Correlation between: EM and clinical attachment level r = 0.58 (p < 0.001), ßSI and clinical attachment level r = 0.66 (p < 0.001), EF and clinical attachment level 0.59 (p < 0.001). CONCLUSIONS: Parameters of arterial stiffness and EF were worse in patients with SPD and correlated moderately with clinical attachment level. Correlation with compliance and EF was negative.

Impact of copper sulfate application at an urban Brazilian reservoir: A geostatistical and ecotoxicological approach.

A landscape ecotoxicology approach was used to assess the spatial distribution of copper in the recent bottom sediment (surficial sediment) of a Brazilian subtropical reservoir (the Guarapiranga reservoir) and its potential ecotoxicological impacts on the reservoir ecosystem and the local society. We discuss the policies and procedures that have been employed for the management of this reservoir over the past four decades. Spatial heterogeneity in the reservoir was evaluated by means of sampling design and statistical analysis based on kriging spatial interpolation. The sediment copper concentrations have been converted into qualitative categories in order to interpret the reservoir quality and the impacts of management policies. This conversion followed the Canadian Water Framework Directive (WFD) ecotoxicological concentration levels approach, employing sediment quality guidelines (SQGs). The SQG values were applied as the copper concentration thresholds for quantitative-qualitative conversion of data for the surficial sediment of the Guarapiranga. The SQGs used were as follows: a) interim sediment quality guideline (ISQG), b) probable effect level (PEL), and c) regional reference value (RRV). The quantitative results showed that the spatial distribution of copper in the recent bottom sediment reflected the reservoir's management policy and the copper application protocol, and that the copper concentrations varied considerably, ranging from virtually-zero to in excess of 3gcopper/kgds. The qualitative results demonstrated that the recent bottom sediment was predominantly in a bad or very bad condition, and could therefore have impacts on the local society and the ecosystem. It could be concluded that the management policy for this reservoir was mainly determined by the desire to minimize short-term costs, disregarding long-term socioeconomic and environmental consequences.

Annual and short-term variability in primary productivity by phytoplankton and correlated abiotic factors in the Jurumirim Reservoir (São Paulo, Brazil).

The annual variability of the photosynthetic production (PP) by phytoplankton in the lacustrine zone of the Jurumirim Reservoir (São Paulo, Brazil) was evaluated in a three-year study to identify recurrent patterns and their causes. Variability in PP was measured daily during two periods of the year (the dry and rainy seasons). An analysis of the PP data failed to identify a recurrent pattern, since the PP values showed no correlation with hydrological factors (rainfall, water level and discharge, and washout) nor, apparently, with the waters nutritional conditions. A principal component analysis revealed that the PP and assimilation ratio were higher when the PO4(3-) and N-NH(4+) contents were low and the ZEU/ZMIX ratios were at their highest. Areal primary productivity can be predicted based on the ratio between the maximum volumetric productivity and the coefficient of vertical extinction of light. However, the biomass integrated for ZEU was a poor predictor of areal primary productivity. No correlation was found between water temperature and areal and maximum volumetric productivity. Thus, the three-year PP study indicated that the variability pattern is typically chaotic. As for the short-term measurements, the PP was found to be higher in the dry season than in the rainy, although both seasons showed an areal PP variability of 35 to 40%. This pattern was attributed to the daily variation in the nutritional conditions and the magnitude of light penetrating through the water, combined with the mixing of phytoplanktonic cells. A comment about the relationship between primary production by phytoplankton and fish yield is also briefly discussed here.

Automatic limb identification and sleeping parameters assessment for pressure ulcer prevention.

Pressure ulcers (PUs) are common among vulnerable patients such as elderly, bedridden and diabetic. PUs are very painful for patients and costly for hospitals and nursing homes. Assessment of sleeping parameters on at-risk limbs is critical for ulcer prevention. An effective assessment depends on automatic identification and tracking of at-risk limbs. An accurate limb identification can be used to analyze the pressure distribution and assess risk for each limb. In this paper, we propose a graph-based clustering approach to extract the body limbs from the pressure data collected by a commercial pressure map system. A robust signature-based technique is employed to automatically label each limb. Finally, an assessment technique is applied to evaluate the experienced stress by each limb over time. The experimental results indicate high performance and more than 94% average accuracy of the proposed approach.

Sleep state classification using pressure sensor mats.

Sleep state detection is valuable in assessing patient's sleep quality and in-bed general behavior. In this paper, a novel classification approach of sleep states (sleep, pre-wake, wake) is proposed that uses only surface pressure sensors. In our method, a mobility metric is defined based on successive pressure body maps. Then, suitable statistical features are computed based on the mobility metric. Finally, a customized random forest classifier is employed to identify various classes including a new class for pre-wake state. Our algorithm achieves 96.1% and 88% accuracies for two (sleep, wake) and three (sleep, pre-wake, wake) class identification, respectively.

Clustering-based limb identification for pressure ulcer risk assessment.

Bedridden patients have a high risk of developing pressure ulcers. Risk assessment for pressure ulceration is critical for preventive care. For a reliable assessment, we need to identify and track the limbs continuously and accurately. In this paper, we propose a method to identify body limbs using a pressure mat. Three prevalent sleep postures (supine, left and right postures) are considered. Then, predefined number of limbs (body parts) are identified by applying Fuzzy C-Means (FCM) clustering on key attributes. We collected data from 10 adult subjects and achieved average accuracy of 93.2% for 10 limbs in supine and 7 limbs in left/right postures.

Clinical experience with subxiphoid drainage of pericardial effusions.

To assess the effectiveness of subxiphoid pericardial tube drainage for treatment of pericardial effusion, we reviewed 41 consecutive patients who underwent this procedure during a 14-year period. The patients ranged in age from 7 months to 75 years. All were symptomatic preoperatively. The diagnosis of pericardial effusion was confirmed by echocardiogram in all but 2 patients. Eight patients had acute pericardial tamponade. Subxiphoid pericardial drainage was performed under general (n = 35) or local anesthesia (n = 6). A portion of the anterior pericardium was excised in each patient. There were no perioperative deaths. Thirty-day mortality was 19.5%; there were five late deaths. All deaths were unrelated to pericardial effusion or to the operation. One patient had recurrent effusion requiring pericardiocentesis on the 21st postoperative day. He died five days later of extensive lymphoma. Twenty-eight patients were followed from 1 month to 10 years; mean follow-up was 31.5 months. None developed recurrent effusion or pericardial constriction. We conclude that subxiphoid pericardial drainage is effective for treatment of pericardial effusion.

Contribution of aerosols generated during mixing and loading of pesticides to operator inhalation exposure.

The occupational exposure resulting from the application of crop protection agents continues to be of great interest for the purposes of identifying hazards or determining safer chemical handling methods. The purpose of the present study was to identify the potential respirator exposure of a mixer/loader to chlorothalonil, with the mixing and loading operation as the only source of aerosols (particles <13 microm diameter). Three worst-case mixing/loading scenarios were simulated in the lab: (1) a spill of undiluted chlorothalonil formulation onto a dry, horizontal metal surface; (2) a spill of undiluted chlorothalonil formulation onto a rapidly rotating shaft; and (3) pouring undiluted chlorothalonil formulation into a container of water. Aerosol generation from these scenarios was compared to that resulting from atomizing dilute chlorothalonil through hydraulic nozzles. Aerosols were captured with a cascade impactor, and quantified by gas chromatography. Results indicated that simulated spill scenarios generated aerosol concentrations between 2.1 and 5.3 ng/l, which were in the same order of magnitude as, and only marginally higher than, the detection threshold (1.7 ng/l) and background levels (2.2 ng/l). In comparison, atomization of dilute chlorothalonil through a hollow cone and flat fan nozzles resulted in airborne concentrations of 354 and 96 ng/l, respectively, related to the atomization characteristics of these nozzles. Measurement of the dimensions of the aerosol cloud indicated that aerosols resulting from a spill amounted to approximately 10(-5)% of the spilled chlorothalonil. It was estimated that a male worker respiring 29 l/min would inhale approximately 0.32-0.78 ng of chlorothalonil during a typical 30 s spill, assuming a 1% transfer efficiency between the spill site and the mixer/loader. These estimates were between 10000 and 480000 times less than literature data for respiratory exposure of chlorothalonil by applicators and harvesters, suggesting that inhalation of aerosols from mixing and loading represents a minor component of overall exposure.

Activity of moxifloxacin in combination with vancomycin or teicoplanin against Staphylococcus aureus isolated from device-associated infections unresponsive to glycopeptide therapy.

We tested the in vitro bactericidal activity of moxifloxacin, a new 8-methoxyquinolone, alone and in combination with vancomycin or teicoplanin at different multiples of minimum inhibitory concentration (MIC) against 8 methicillin-ciprofloxacin-resistant Staphylococcus aureus (M-C-RSA) and 1 methicillin-ciprofloxacin susceptible S. aureus (M-C-SSA) recently isolated from device-associated infections unresponsive to or relapsing after glycopeptide therapy, despite device removal. MICs of vancomycin ranged from 1 to 4 microg/ml, MICs of teicoplanin ranged from 2 to 8 microg/ml; MICs of moxifloxacin were always 2 microg/ml against M-C-RSA isolates and 0.125 microg/ml against the M-C-SSA isolate. The 9 strains resulted tolerant when tested for vancomycin, teicoplanin, and moxifloxacin used alone at 2 x MIC. In all cases the combination of moxifloxacin and teicoplanin or vancomycin appeared to be bactericidal already at MIC concentration for glycopeptides plus 0.5 x MIC concentration for moxifloxacin. If these results are confirmed in vivo in animal experiments, the combination of moxifloxacin with glycopeptides might be useful for treating device-associated infections, and in preventing the frightening phenomenon of increasing MICs for glycopeptides.

Methicillin-resistant staphylococcal bacteremia in patients with hematologic malignancies: clinical and microbiological retrospective comparative analysis of S. haemolyticus, S. epidermidis and S. aureus.

Although Staphylococcus haemolyticus (SH) represents an emerging etiology of methicillin-resistant (MR) coagulase-negative staphylococcal nosocomial bacteremia, little is known of clinical significance of this infection. Thus, we performed case-control retrospective comparative analysis of MRSH bacteremias (MRSHB), methicillin-resistant S. epidermidis bacteremias (MRSEB), and methicillin-resistant S. aureus bacteremias (MRSAB) in patients with hematologic malignancies. Most patients in the three groups were neutropenic and had a central venous catheter (CVC) in place at the onset of bacteremia. However, MRSHB patients had a CVC in place prior to bacteremia for a time significantly more prolonged than MRSEB and MRSAB ones (p<0.05). Severe sepsis or septic shock were more common in patients with MRSAB as compared with MRSHB (p=0.02). Nosocomial attributable mortality rate was very low in the 3 study groups (0 to 5.4%) and only two patients developed metastatic infections. Overall, reduced susceptibility to teicoplanin was observed in 19 (47.5%) MRSH and in 4 (10%) MRSE isolates. Resistance to teicoplanin was observed in 6 isolates, all MRSH. Reduced susceptibility or resistance to vancomycin was observed in 2 isolates, both MRSH. All MRSA isolates were susceptible to the glycopeptides. Comparison between cases of bacteremia in patients with MRSH isolates with reduced susceptibility to teicoplanin and those with susceptible MRSH did not reveal significant differences in the clinical-microbiological response to teicoplanin therapy and outcome. Our results seem to suggest that MRSHB in hematologic patients is associated with low morbidity and mortality rates. MRSH frequently shows a reduced susceptibility to teicoplanin; however these in vitro data do not seem associated with an unfavorable clinical response to teicoplanin therapy for MRSHB in patients with hematologic malignancies.

Sacral and ischial pressure ulcers: evaluation, treatment, and differentiation.

Although the cost of caring for pressure ulcers is enormous, few accepted standards of care exist in the fragmented specialty of wound care. This review attempts to establish a standardized approach to the evaluation and treatment of sacral and ischial wounds, and to describe some important differences. Topics reviewed include important elements of the history, physical, and laboratory studies of patients with wounds. Treatment issues are also addressed including wound care, pressure relief, and nutrition. The authors hope that the principles discussed will stimulate caregivers to examine their practices, and will serve as a starting point for formation of more exacting accepted care. While each patient and wound may require subtle nuances of care in certain areas, a more uniform set of standards will be the first step in creating delivery systems that are geared for large-scale prospective randomized studies that are so desperately needed in most areas of wound care.

The role of "wound burden" in determining the costs associated with wound care.

Because of the tremendous resources they require to heal, patients with severe wounds present significant challenges to our healthcare system. This study was undertaken to introduce the concept of "wound burden" and its predictive value in anticipating the costs associated with inpatient care for patients with wounds. Wound burden is a new concept that can be used to represent the severity of a patient's skin breakdown; it is defined in this study in terms of number, size, and stage. A computerized system of wound cost tracking measured the costs involved in delivering optimal wound care to 240 patients in a long-term acute care facility. Patients were stratified in a system that accounted for "wound burden" to determine the degree to which wound burden is related to costs. Costs that pertained to supplies, specialty beds, nutrition, labs, and extra personnel time required to document and care for the wounds were recorded. The concept of "wound burden" was presented and found to be very important in predicting actual costs. Patients with the highest level of wound burden were found to have significantly higher wound costs and total stay costs (P > 0.0001). As payment systems change, having data available to justify the resources necessary to allow facilities to continue to care for the most highly wound burdened patients will become increasingly important.

The water level influence on biomass of Echinochloa polystachya (Poaceae) in the Jurumirim Reservoir (São Paulo, Brazil).

In the Paranapanema River mouth, Jurumirim Reservoir (23 degrees 27'-23 degrees 29'S and 48 degrees 39'-48 degrees 36'W, SP, Brazil), the biomass of E. polystachya was monthly determined with eight quadrats of 0.25 m2 from August 1993 to July 1994. The seasonal variation in biomass was unimodal, with greater biomass from November 1993 to April 1994. The average biomass was 1,933.7 +/- 479.5 gDW.m-2, with a variation along the year from 1,149.0 to 2,755.9 gDW.m-2. The annual variation of aerial green biomass, aerial and aquatic detritus suggest that the main growth period of E. polystachya was from December 1993 to May 1994, with peak between February to March 1994. The data indicate that this macrophyte is adapted to water level variation.

Classifying bed inclination using pressure images.

Pressure ulcer is one of the most prevalent problems for bed-bound patients in hospitals and nursing homes. Pressure ulcers are painful for patients and costly for healthcare systems. Accurate in-bed posture analysis can significantly help in preventing pressure ulcers. Specifically, bed inclination (back angle) is a factor contributing to pressure ulcer development. In this paper, an efficient methodology is proposed to classify bed inclination. Our approach uses pressure values collected from a commercial pressure mat system. Then, by applying a number of image processing and machine learning techniques, the approximate degree of bed is estimated and classified. The proposed algorithm was tested on 15 subjects with various sizes and weights. The experimental results indicate that our method predicts bed inclination in three classes with 80.3% average accuracy.

Evaluación toxicológica y de metales (Cu, Pb, Ni, Zn y Cd) en el sedimento del reservorio Paiva Castro en Mairiporã-SP, Brasil / Toxicological and metal evaluation (Cu, Pb, Ni, Zn and Cd) in the sediment of Paiva Castro reservoir, in Mairiporã-SP, Brasil

El hombre ha cambiado el ambiente para sostener la demanda global de recursos naturales como el agua. La gestión de los cuerpos hídricos tiene que ser constante, con el propósito preventivo y correctivo, dependiendo del estado de antropización de cada sistema. El objetivo de este artículo fue analizar la toxicidad del sedimento y los metales Mn, Zn, Pb, Ni, Cd y Cu, en el reservorio Paiva Castro, que abastece la Region Metropolitana de São Paulo. Se realizaron 2 muestreos (Mayo 2011, estación seca y Enero de 2012, estación húmeda) y se analizaron 5 puntos próximos a la captación de agua por la Companhia de Saneamento Básico do Estado de São Paulo. Se realizaron ensayos de toxicidad aguda y crónica en sedimento, a través de ensayos biológicos con el cladócero Daphnia similis y el insecto Chironomus xanthus. El tratamiento de datos se realizó con el test de Fisher (mortalidad). El nivel de asociación entre las variables en sedimento y en los test ecotoxicológicos fueron evaluados por test no-paramétricos, a través del coeficiente de correlación de Spearman's. Los resultados del presente trabajo señalaron bajas concentracones de metales en el sedimento del área de estudio y ausencia de toxicidad en los organismos ensayados. Se puede concluir que área estudiada del reservorio Paiva Castro se encuentra poco impactada por los metales, sin efectos directos sobre la calidad de vida los organismos bentónicos: D. similis y C. xanthus.

Man had changed the natural environment in an attempt trying to supply the global demand for resources. The management of the hydric bodies has to be constant, with preventive and corrective purpose, depending on the eutrophization state of each one. The objective of this article was to analyze the sediment toxicity and the metals Mn, Zn, Pb, Ni, Cd and Cu, in the Paiva Castro reservoir, that supply the Metropolitan Region of São Paulo. It was made 2 collections (May 2011, dry season and January 2012, wet season). It was analyzed 5 points next to the water captation station by the Companhia de Saneamento Básico do Estado de São Paulo. The sediment was analyzed as for acute and chronic toxicity through bioassays with the cladocerans Daphnia similis and the insect Chironomus xanthus. Data treatment was done with Fisher Exact Test (mortality). The association level between the variables in sediment and ecotoxicological tests was available in non-parametric tests, through the Spearman's correlation coefficient. Oriented on the results presented in this work, pointing low concentrations of heavy metals in the sediments presented in the collect local, and the absence of toxicity, we can say that at this reservoir, at least in the collect area, it's low impacted, not implicating in direct interferences in the quality of life of benthonic organisms.

Bed posture classification for pressure ulcer prevention.

Pressure ulcer is an age-old problem imposing a huge cost to our health care system. Detecting and keeping record of the patient's posture on bed, help care givers reposition patient more efficiently and reduce the risk of developing pressure ulcer. In this paper, a commercial pressure mapping system is used to create a time-stamped, whole-body pressure map of the patient. An image-based processing algorithm is developed to keep an unobtrusive and informative record of patient's bed posture over time. The experimental results show that proposed algorithm can predict patient's bed posture with up to 97.7% average accuracy. This algorithm could ultimately be used with current support surface technologies to reduce the risk of ulcer development.

Annual and short-term variability in primary productivity by phytoplankton and correlated abiotic factors in the Jurumirim Reservoir (São Paulo, Brazil)

The annual variability of the photosynthetic production (PP) by phytoplankton in the lacustrine zone of the Jurumirim Reservoir (São Paulo, Brazil) was evaluated in a three-year study to identify recurrent patterns and their causes. Variability in PP was measured daily during two periods of the year (the dry and rainy seasons). An analysis of the PP data failed to identify a recurrent pattern, since the PP values showed no correlation with hydrological factors (rainfall, water level and discharge, and washout) nor, apparently, with the water’s nutritional conditions. A principal component analysis revealed that the PP and assimilation ratio were higher when the PO4(3-) and N-NH4+ contents were low and the Z EU/Z MIX ratios were at their highest. Areal primary productivity can be predicted based on the ratio between the maximum volumetric productivity and the coefficient of vertical extinction of light. However, the biomass integrated for Z EU was a poor predictor of areal primary productivity. No correlation was found between water temperature and areal and maximum volumetric productivity. Thus, the three-year PP study indicated that the variability pattern is typically chaotic. As for the short-term measurements, the PP was found to be higher in the dry season than in the rainy, although both seasons showed an areal PP variability of 35 to 40%. This pattern was attributed to the daily variation in the nutritional conditions and the magnitude of light penetrating through the water, combined with the mixing of phytoplanktonic cells. A comment about the relationship between primary production by phytoplankton and fish yield is also briefly discussed here.

A variabilidade anual da produção fotossintética (PP) pelo fitoplâncton na zona da barragem da Represa de Jurumirim (São Paulo, Brasil) foi medida após um estudo no período de três anos sucessivos, com o objetivo de identificar padrões recorrentes e suas causas. Medidas da variabilidade da PP em escala diária foram obtidas em dois períodos do ano (estações seca e chuvosa). Nenhum padrão recorrente foi verificado nos dados de PP, visto não haver relação de sua variabilidade com nenhum fator hidrológico (precipitação, nível e vazão de água e washout) nem, aparentemente, com as condições nutritivas da água. A análise de componentes principais revelou que a PP e a taxa de assimilação foram mais elevadas na época do ano em que o conteúdo de PO4(3-) e N-NH4+ foi mais baixo e quando as razões Z EU/Z MIX foram mais elevadas. A produtividade primária/área pode ser estimada pela razão entre a produtividade volumétrica máxima e o coeficiente de extinção vertical da luz. Entretanto, a biomassa integrada na Z EU foi um pobre preditor da produtividade primária/área. Nenhuma correlação foi encontrada entre a temperatura da água com a produtividade primária (por área e volumétrica máxima). Em conseqüência, o estudo da PP em três anos sucessivos mostrou que o padrão de variabilidade é tipicamente caótico. Em relação às medidas de curta duração, maior PP foi encontrada na estação seca do que na chuvosa. Em ambos os períodos, a variabilidade da PP (por área) foi de aproximadamente 35-40%. O padrão foi atribuído não somente à variação na concentração dos nutrientes mas também à magnitude de penetração de luz na água associado ao regime de circulação. Um comentário sobre a relação entre produção primária pelo fitoplâncton com produção pesqueira é também apresentada.

Annual and short-term variability in primary productivity by phytoplankton and correlated abiotic factors in the Jurumirim Reservoir (São Paulo, Brazil)

A variabilidade anual da produção fotossintética (PP) pelo fitoplâncton na zona da barragem da Represa de Jurumirim (São Paulo, Brasil) foi medida após um estudo no período de três anos sucessivos, com o objetivo de identificar padrões recorrentes e suas causas. Medidas da variabilidade da PP em escala diária foram obtidas em dois períodos do ano (estações seca e chuvosa). Nenhum padrão recorrente foi verificado nos dados de PP, visto não haver relação de sua variabilidade com nenhum fator hidrológico (precipitação, nível e vazão de água e washout) nem, aparentemente, com as condições nutritivas da água. A análise de componentes principais revelou que a PP e a taxa de assimilação foram mais elevadas na época do ano em que o conteúdo de PO43- e NûNH4+ foi mais baixo e quando as razões ZEU/ZMIX foram mais elevadas. A produtividade primária/área pode ser estimada pela razão entre a produtividade volumétrica máxima e o coeficiente de extinção vertical da luz. Entretanto, a biomassa integrada na ZEU foi um pobre preditor da produtividade primária/área. Nenhuma correlação foi encontrada entre a temperatura da água com a produtividade primária (por área e volumétrica máxima). Em conseqüência, o estudo da PP em três anos sucessivos mostrou que o padrão de variabilidade é tipicamente caótico. Em relação às medidas de curta duração, maior PP foi encontrada na estação seca do que na chuvosa. Em ambos os períodos, a variabilidade da PP (por área) foi de aproximadamente 35-40%. O padrão foi atribuído não somente à variação na concentração dos nutrientes mas também à magnitude de penetração de luz na água associado ao regime de circulação. Um comentário sobre a relação entre produção primária pelo fitoplâncton com produção pesqueira é também apresentada.

The water level influence on biomass of Echinochloa polystachya (Poaceae) in the Jurumirim Reservoir (São Paulo, Brazil)

In the Paranapanema River mouth, Jurumirim Reservoir (23§27'-23§29'S and 48§39'-48§36'W, SP, Brazil), the biomass of E. polystachya was monthly determined with eight quadrats of 0.25 m² from August 1993 to July 1994. The seasonal variation in biomass was unimodal, with greater biomass from November 1993 to April 1994. The average biomass was 1,933.7 + or - 479.5 gDW.m-2, with a variation along the year from 1,149.0 to 2,755.9 gDW.m-2. The annual variation of aerial green biomass, aerial and aquatic detritus suggest that the main growth period of E. polystachya was from December 1993 to May 1994, with peak between February to March 1994. The data indicate that this macrophyte is adapted to water level variation