El efecto de arroyos tributarios de menor orden sobre el perifiton de un río de llanura

Confluence zones are important places to analyze discontinuities that succeed in the river continuum, when two streams of different order link up with their collector. In this work we analyzed the periphyton composition and structure in the confluence of two mountain streams, where Chocancharava river (Cuarto river) foothill reach begins, in Córdoba province. Monthly periphyton samples were taken by scraping a known surface, in three sites located in Piedras Blancas and San Bartolomé stream confluence at 550 m a.s.l. TWINSPAN classification and sample and species ordinations by means of Canonic Correspondence Analysis (CCA) were carried out. Seventy one algae species were determined. Bacillarophyceae and Chlorophyceae presented higher species richness. Dominant species were Cocconeis placentula var. euplypta and Achnanthidium minutissimum, both exhibited an annual bimodal distribution pattern, with maximal densities in autumn and spring. CCA clusters demonstrated seasonal changes in periphyton structure. Summer species were associated to higher temperature and precipitations, and winter species (were associated) to higher conductivity and pH. The tributary of minor order, San Bartolomé stream, evidenced a wider distance in the sample grouping; its flora was different in winter months, during the phase of low water levels. From the obtained results it is concluded that at the confluence sectors the composition and structure of the higher order stream is continuous with the principal river during low water levels while, during high water levels, the periphyton of both tributaries colonize the receiving river.Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Instituto de Limnología "Dr. Raul A. Ringuelet" (ILPLA

El efecto de arroyos tributarios de menor orden sobre el perifiton de un río de llanura

Confluence zones are important places to analyze discontinuities that succeed in the river continuum, when two streams of different order link up with their collector. In this work we analyzed the periphyton composition and structure in the confluence of two mountain streams, where Chocancharava river (Cuarto river) foothill reach begins, in Córdoba province. Monthly periphyton samples were taken by scraping a known surface, in three sites located in Piedras Blancas and San Bartolomé stream confluence at 550 m a.s.l. TWINSPAN classification and sample and species ordinations by means of Canonic Correspondence Analysis (CCA) were carried out. Seventy one algae species were determined. Bacillarophyceae and Chlorophyceae presented higher species richness. Dominant species were Cocconeis placentula var. euplypta and Achnanthidium minutissimum, both exhibited an annual bimodal distribution pattern, with maximal densities in autumn and spring. CCA clusters demonstrated seasonal changes in periphyton structure. Summer species were associated to higher temperature and precipitations, and winter species (were associated) to higher conductivity and pH. The tributary of minor order, San Bartolomé stream, evidenced a wider distance in the sample grouping; its flora was different in winter months, during the phase of low water levels. From the obtained results it is concluded that at the confluence sectors the composition and structure of the higher order stream is continuous with the principal river during low water levels while, during high water levels, the periphyton of both tributaries colonize the receiving river.Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Instituto de Limnología "Dr. Raul A. Ringuelet" (ILPLA

Calidad ambiental en un río urbano de llanura

Environmental quality in a lowland urban river. Ecological integrity or health of a river is evaluated not only by the physical chemical and biological characteristics in the fluvial channel but also by the state of the riparian systems. Attributes of the benthic communities and the riparian areas are integrated to the chemical macroindicators. The objective of this work is to evaluate the environmental quality of the Chocancharava river plain reach in the urban sector and surroundings of Río Cuarto city. Three study sites were selected: in pre-urban, urban and post-urban reaches. Sampling and field data collections were made in two different hydrological periods: winter and summer. Physical and chemical data were registered and benthos samples were taken from transects across different habitats with a Hess sampler. Multimetric indices from structural attributes such as richness, composition and tolerance/intolerance were calculated. The riparian forest quality (RFQ) was evaluated. The obtained score enabled to describe the ecological status. The physical and chemical indicators showed good water quality and the multimetric indices determined a low impaired biological quality. The application of RFQ index showed an extreme degradation of the riparian system quality. The combination of the indices determined a bad ecological status. The results of this study contribute to corroborate that the Chocancharava river, in the urban sector and its surroundings, presents environmental deterioration, and that remediation and improvement measures are necessary.Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Instituto de Limnología "Dr. Raul A. Ringuelet" (ILPLA

Calidad ambiental en un río urbano de llanura

Environmental quality in a lowland urban river. Ecological integrity or health of a river is evaluated not only by the physical chemical and biological characteristics in the fluvial channel but also by the state of the riparian systems. Attributes of the benthic communities and the riparian areas are integrated to the chemical macroindicators. The objective of this work is to evaluate the environmental quality of the Chocancharava river plain reach in the urban sector and surroundings of Río Cuarto city. Three study sites were selected: in pre-urban, urban and post-urban reaches. Sampling and field data collections were made in two different hydrological periods: winter and summer. Physical and chemical data were registered and benthos samples were taken from transects across different habitats with a Hess sampler. Multimetric indices from structural attributes such as richness, composition and tolerance/intolerance were calculated. The riparian forest quality (RFQ) was evaluated. The obtained score enabled to describe the ecological status. The physical and chemical indicators showed good water quality and the multimetric indices determined a low impaired biological quality. The application of RFQ index showed an extreme degradation of the riparian system quality. The combination of the indices determined a bad ecological status. The results of this study contribute to corroborate that the Chocancharava river, in the urban sector and its surroundings, presents environmental deterioration, and that remediation and improvement measures are necessary.Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Instituto de Limnología "Dr. Raul A. Ringuelet" (ILPLA

Calidad ambiental en un río urbano de llanura

Environmental quality in a lowland urban river. Ecological integrity or health of a river is evaluated not only by the physical chemical and biological characteristics in the fluvial channel but also by the state of the riparian systems. Attributes of the benthic communities and the riparian areas are integrated to the chemical macroindicators. The objective of this work is to evaluate the environmental quality of the Chocancharava river plain reach in the urban sector and surroundings of Río Cuarto city. Three study sites were selected: in pre-urban, urban and post-urban reaches. Sampling and field data collections were made in two different hydrological periods: winter and summer. Physical and chemical data were registered and benthos samples were taken from transects across different habitats with a Hess sampler. Multimetric indices from structural attributes such as richness, composition and tolerance/intolerance were calculated. The riparian forest quality (RFQ) was evaluated. The obtained score enabled to describe the ecological status. The physical and chemical indicators showed good water quality and the multimetric indices determined a low impaired biological quality. The application of RFQ index showed an extreme degradation of the riparian system quality. The combination of the indices determined a bad ecological status. The results of this study contribute to corroborate that the Chocancharava river, in the urban sector and its surroundings, presents environmental deterioration, and that remediation and improvement measures are necessary.Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Instituto de Limnología "Dr. Raul A. Ringuelet" (ILPLA

Self-induced parametric amplification arising from nonlinear elastic coupling in a micromechanical resonating disk gyroscope

Parametric amplification, resulting from intentionally varying a parameter in a resonator at twice its resonant frequency, has been successfully employed to increase the sensitivity of many micro- and nano-scale sensors. Here, we introduce the concept of self-induced parametric amplification, which arises naturally from nonlinear elastic coupling between the degenerate vibration modes in a micromechanical disk-resonator, and is not externally applied. The device functions as a gyroscope wherein angular rotation is detected from Coriolis coupling of elastic vibration energy from a driven vibration mode into a second degenerate sensing mode. While nonlinear elasticity in silicon resonators is extremely weak, in this high quality-factor device, ppm-level nonlinear elastic effects result in an order-of-magnitude increase in the observed sensitivity to Coriolis force relative to linear theory. Perfect degeneracy of the primary and secondary vibration modes is achieved through electrostatic frequency tuning, which also enables the phase and frequency of the parametric coupling to be varied, and we show that the resulting phase and frequency dependence of the amplification follow the theory of parametric resonance. We expect that this phenomenon will be useful for both fundamental studies of dynamic systems with low dissipation and for increasing signal-to-noise ratio in practical applications such as gyroscopes

Predictive factors for lymph node involvement in sporadic medullary thyroid microcarcinoma: A systematic review

Objective: The aim of the study was to determine the impact of laboratory and imaging tests in predicting central and lateral neck lymph node/LN involvement and in decision making for surgical extent. Materials and Methods: A PubMed, Web of Science and Scopus search was performed according to PRISMA criteria. The relationship between nodule size, diagnostic biomarkers and imaging with LN involvement were evaluated. Results: The available data analysis did not yield clear indications of the relationship between each of these topics and the presence, number, and location of LN involved. There was no conclusive data for the selective indication of central neck dissection in the preoperative diagnosis of microMTC. Conclusions: There is no justification for less invasive interventions than total thyroidectomy with lymph node dissection

Interpretation of intraoperative parathyroid hormone monitoring according to the Rome criterion in primary hyperparathyroidism

Intraoperative parathyroid hormone dosage allows real-time monitoring of the decrease in PTH levels during parathyroidectomy and verify procedure’s efficacy. Currently, none of the interpretative criteria used has absolute accuracy. The aim of this study is to evaluate diagnostic accuracy of the Rome criterion verifying diagnostic significance of the individual assays. A total of 205 patients with primary hyperparathyroidism from a single adenoma were retrospectively evaluated and monitored with baseline PTH, PTH at 10 min and PTH at 20 min after adenoma excision. The accuracy of the latter two assays compared with baseline was compared by ROC curves. In addition, was evaluated the influence on these data of localization diagnostics (ultrasounds and scintigraphy), definitive histology, and type of surgery performed. The ratio of 20-min sampling to baseline in the Rome criterion showed highest diagnostic significance. This finding was not influenced by the type of surgery performed, definitive histologic examination, or intraoperative localization of the adenoma. The Rome criterion has shown its high reliability in detecting persistence. The ratio of sampling at 20 min to baseline is by far the best performing. Further studies are needed to evaluate whether sampling at 10 min after adenoma excision can be considered not mandatory

Indole and 2,4-Thiazolidinedione conjugates as potential anticancer modulators

Background. Thiazolidinediones (TZDs), also called glitazones, are five-membered carbon ring molecules commonly used for the management of insulin resistance and type 2 diabetes. Recently, many prospective studies have also documented the impact of these compounds as anti-proliferative agents, though several negative side effects such as hepatotoxicity, water retention and cardiac issues have been reported. In this work, we synthesized twenty-six new TZD analogues where the thiazolidinone moiety is directly connected to an N-heterocyclic ring in order to lower their toxic effects. Methods. By adopting a widely applicable synthetic method, twenty-sixTZDderivatives were synthesized and tested for their antiproliferative activity in MTT and Wound healing assays with PC3 (prostate cancer) and MCF-7 (breast cancer) cells. Results. Three compounds, out of twenty-six, significantly decreased cellular viability and migration, and these effects were even more pronounced when compared with rosiglitazone, a well-known member of the TZD class of antidiabetic agents. As revealed by Western blot analysis, part of this antiproliferative effect was supported by apoptosis studies evaluating BCL-xL and C-PARP protein expression. Conclusion. Our data highlight the promising potential of these TZD derivatives as anti-proliferative agents for the treatment of prostate and breast cancer

Predicting the Closed-Loop Stability and Oscillation Amplitude of Nonlinear Parametrically Amplified Oscillators

This work investigates the closed-loop operation of microelectromechanical oscillators in the presence of both cubic (Duffing) nonlinearities and parametric amplification. We present a theoretical model for this system that enables us to predict oscillation amplitude and instability and experimentally verify it using a silicon disk resonator with a quality factor (Q) of 85 000 and a natural frequency of 251 kHz. We determine that, contrary to previous understanding gained from analyzing the open-loop system, the presence of cubic nonlinearities does not limit the maximum stable oscillation amplitude if the resonator is operated in a closed loop. In addition, the stability and amplitude behavior predicted by our theoretical model are independent of the presence or severity of cubic nonlinearities, or on drive amplitude