Incidencia del espectro de acretismo placentario en la unidad de cuidados intensivos obstétricos del Hospital de la Mujer de Sinaloa / Incidence of the placental accretism spectrum in the obstetric intensive care unit of the Hospital de la Mujer of Sinaloa

Resumen OBJETIVO: Determinar la incidencia del espectro del acretismo placentario en pacientes ingresadas a la unidad de cuidados intensivos obstétricos del Hospital de la Mujer, Culiacán, Sinaloa. MATERIALES Y MÉTODOS: Estudio retrospectivo, transversal y descriptivo fundamentado en el análisis de la base de datos del Hospital de la Mujer de pacientes internadas entre los años 2017 a 2020 con diagnóstico de espectro de placenta acreta, referidas o diagnosticadas en la institución e intervenidas para histerectomía por la complicación estudiada. RESULTADOS: Se analizaron 22 pacientes con diagnóstico de acretismo placentario que dieron una incidencia de 0.09%; de éstas, a 1 se le indicó cesárea; 19 de las 22 pacientes tenían antecedente de cicatriz uterina previa, todas con placenta previa. El promedio de edad fue de 30.86 ± 4 años. La cesárea se practicó, en promedio, a las 34 semanas de embarazo con dos técnicas quirúrgicas. El sangrado promedio estimado fue de 1.947 mL. Las complicaciones transoperatorias fueron las lesiones: ureteral (n = 2) y vesical (n = 1). La principal complicación posoperatoria fue la fístula vesicouterina (n = 1). El promedio de estancia fue de 2 días en 16 de las 22 pacientes y de 7 días en las 6 restantes. CONCLUSIONES: Lo importante del acretismo placentario es el diagnóstico oportuno que permita derivar a las pacientes a centros hospitalarios que cuenten con especialistas experimentados en la atención de estos casos.

Abstract OBJECTIVE: To determine the incidence of placental accretism spectrum in pregnant women admitted to the obstetric intensive care unit of the Hospital de la Mujer, Culiacán, Sinaloa. MATERIALS AND METHODS: Retrospective, cross-sectional, descriptive study based on the analysis of the database of the Hospital de la Mujer of patients admitted between 2017 and 2020 with a diagnosis of placenta accreta spectrum, referred or diagnosed at the institution and underwent hysterectomy for the complication studied. RESULTS: Twenty-two patients with a diagnosis of placenta accreta were analysed, giving a prevalence of 0.09%; of these, caesarean section was indicated in 0.2%. 19 of the 22 patients had a history of previous uterine scarring, all with placenta praevia. Mean age was 30.86 ± 4 years. Caesarean section was performed at a mean gestational age of 34 weeks using two surgical techniques. The mean estimated blood loss was 1,947 mL. The most common operative complications were ureteral (n = 2) and bladder (n = 1) injuries. The most common postoperative complication was vesico-uterine fistula (n = 1). The mean length of stay was 2 days in 16 of the 22 patients and 7 days in the remaining 6 patients. CONCLUSIONS: The most important aspect of placenta accreta is early diagnosis, which allows referral to hospital centres with specialists experienced in the management of these cases.

BRCA1 frameshift variants leading to extended incorrect protein C termini.

Carriers of BRCA1 germline pathogenic variants are at substantially higher risk of developing breast and ovarian cancer than the general population. Accurate identification of at-risk individuals is crucial for risk stratification and the implementation of targeted preventive and therapeutic interventions. Despite significant progress in variant classification efforts, a sizable portion of reported BRCA1 variants remain as variants of uncertain clinical significance (VUSs). Variants leading to premature protein termination and loss of essential functional domains are typically classified as pathogenic. However, the impact of frameshift variants that result in an extended incorrect terminus is not clear. Using validated functional assays, we conducted a systematic functional assessment of 17 previously reported BRCA1 extended incorrect terminus variants (EITs) and concluded that 16 constitute loss-of-function variants. This suggests that most EITs are likely to be pathogenic. However, one variant, c.5578dup, displayed a protein expression level, affinity to known binding partners, and activity in transcription and homologous recombination assays comparable to the wild-type BRCA1 protein. Twenty-three additional carriers of c.5578dup were identified at a US clinical diagnostic lab and assessed using a family history likelihood model providing, in combination with the functional data, a likely benign interpretation. These results, consistent with family history data in the current study and available data from ClinVar, indicate that most, but not all, BRCA1 variants leading to an extended incorrect terminus constitute loss-of-function variants and underscore the need for comprehensive assessment of individual variants.

No evidence of predicted phenotypic changes after hurricane disturbance in a shade-specialist Caribbean anole.

Extreme climatic events (ECEs) such as hurricanes have been hypothesized to be a major driving force of natural selection. Recent studies argue that, following strong hurricane disturbance, Anolis lizards in the Caribbean undergo selection for traits such as longer forelimbs or smaller body sizes that improve their clinging ability to their substrates increasing their chances of surviving hurricane wind gusts. Some authors challenge the generalization of this hypothesis arguing that other mechanisms may explain these phenotypic changes or that they may not necessarily be generalizable across systems. To address this issue, we compared body size and relative forelimb length of Anolis gundlachi, a trunk-ground anole living in closed-canopy forests in Puerto Rico, before, four months after, and 15 months after Hurricanes Irma and Maria in 2017. Overall, our results show no clear evidence of a temporal decrease in body size or increase forelimb length (relative to body size) challenging the generalizability of the clinging ability hypothesis. Understanding how animals adapt to ECE is an emerging field. Still, we are quickly learning that this process is complex and nuanced.

A wiring diagram to integrate physiological traits of wheat yield potential.

As crop yields are pushed closer to biophysical limits, achieving yield gains becomes increasingly challenging and will require more insight into deterministic pathways to yields. Here, we propose a wiring diagram as a platform to illustrate the interrelationships of the physiological traits that impact wheat yield potential and to serve as a decision support tool for crop scientists. The wiring diagram is based on the premise that crop yield is a function of photosynthesis (source), the investment of assimilates into reproductive organs (sinks) and the underlying processes that enable expression of both. By illustrating these linkages as coded wires, the wiring diagram can show connections among traits that may not have been apparent, and can inform new research hypotheses and guide crosses designed to accumulate beneficial traits and alleles in breeding. The wiring diagram can also serve to create an ever-richer common point of reference for refining crop models in the future.

Biomodex patient-specific brain aneurysm models: the value of simulation for first in-human experiences using new devices and robotics.

BACKGROUND: With the recent advent of advanced technologies in the field, treatment of neurovascular diseases using endovascular techniques is rapidly evolving. Here we describe our experience with pre-surgical simulation using the Biomodex EVIAS patient-specific 3D-printed models to plan aneurysm treatment using endovascular robotics and novel flow diverter devices. METHODS: Pre-procedural rehearsals with 3D-printed patient-specific models of eight cases harboring brain aneurysms were performed before the first in-human experiences. To assess the reliability of the experimental model, the characteristics of the aneurysms were compared between the patient and 3D models. The rehearsals were used to define the patient treatment plan, including technique, device sizing, and operative working projections. RESULTS: The study included eight patients with their respective EVIAS 3D aneurysm models. Pre-operative simulation was performed for the first in-human robotic-assisted neurovascular interventions (n=2) and new generation flow-diverter stents (n=6). Aneurysms were located in both the anterior (n=5) and posterior (n=3) circulation and were on average 11.0±6.5 mm in size. We found reliable reproduction of the aneurysm features and similar dimensions of the parent vessel anatomy between the 3D models and patient anatomy. Information learned from pre-surgical in vitro simulation are described in detail, including an improved patient treatment plan, which contributed to successful first in-world procedures with no intraprocedural complications. CONCLUSIONS: Pre-procedural rehearsal using patient-specific 3D models provides precise procedure planning, which can potentially lead to greater operator confidence, decreased radiation dose and improvements in patient safety, particularly in first in-human experiences.

Women of Reproductive Age Living with HIV in Argentina: Unique Challenges for Reengagement in Care.

This study evaluated the reasons for not taking antiretroviral treatment (ART) among women of reproductive age who are disengaged from HIV care (have missed pharmacy pickups and physician visits), with the goal of identifying strategies for reengagement in HIV care. Participants were cisgender women (n = 162), 18 to 49 years of age, and who completed sociodemographic, medical history, reasons why they were not taking ART, mental health, motivation, and self-efficacy assessments. Latent class analysis was used for analysis. Women who reported avoidance-based coping (avoid thinking about HIV) had higher depression (U = 608.5, z = -2.7, P = .007), lower motivation (U = 601, z = -2.8, P = .006), and lower self-efficacy (U = 644.5, z = -2.4, P = .017) than those not using this maladaptive strategy. As women living with HIV experience a disproportionate burden of poor health outcomes, interventions focused on the management of depression may improve HIV outcomes and prevent HIV transmission.

The cytotoxic effect of TiF4 and NaF on fibroblasts is influenced by the experimental model, fluoride concentration and exposure time.

OBJECTIVE: Titanium tetrafluoride (TiF4) has shown promising effect in preventing tooth lesions. Therefore, we compared the cytotoxicity of TiF4 with sodium fluoride (NaF) (already applied in Dentistry) considering different fluoride concentrations, pH values and experimental models. MATERIALS AND METHODS: Step 1) NIH/3T3 fibroblasts were exposed to mediums containing NaF or TiF4 (from 0.15 to 2.45% F), both at native and adjusted pH, for 6 h. Step 2) NIH/3T3 were exposed to NaF or TiF4 varnishes with 0.95, 1.95 or 2.45% F (native pH), for 6, 12 or 24 h. We applied MTT (1st and 2nd steps) and Hoescht/PI stain (2nd step) assays. Step 3) NIH/3T3 were exposed to NaF or TiF4 varnish (2.45% F), at native pH, for 6 or 12 h. The cell stiffness was measured by atomic force microscopy (AFM). RESULTS: Step 1) All cells exposed to NaF or TiF4 mediums died, regardless of the F concentration and pH. Step 2) Both varnishes, at 1.90 and 2.45% F, reduced cell viability by similar extents (33-86% at 6 h, 35-93% at 12 h, and 87-98% at 24 h) compared with control, regardless of the type of fluoride. Varnishes with 0.95% F did not differ from control. Step 3) TiF4 and NaF reduced cell stiffness to a similar extent, but only TiF4 differed from control at 6 h. CONCLUSIONS: Based on the results of the 3 experimental steps, we conclude that TiF4 and NaF have similar cytotoxicity. The cytotoxicity was dependent on F concentration and exposure time. This result gives support for testing the effect of TiF4 varnish in vivo.

Patterns of clozapine and other antipsychotics prescriptions in patients with treatment-resistant schizophrenia in community mental health centers in São Paulo, Brazil

Abstract Background Despite of its global underuse, clozapine is still the golden standard antipsychotic for patients with treatment-resistant schizophrenia (TRS). Objective To evaluate the patterns of clozapine and other antipsychotic drugs prescription in TRS in community mental health centers in São Paulo, Brazil. Methods A multiple-choice questionnaire was applied to fifteen psychiatrists at five centers inquiring about patients’ clinical condition, adherence to oral treatment and current antipsychotic treatment. History of previous and current antipsychotic treatment was collected through medical chart review. Results Out of 442 schizophrenia patients, 103 (23.3%) fulfilled the criteria for TRS. Fifty-eight patients (56.3%) were receiving polypharmacy; 30 (29.1%) were on atypical antipsychotic monotherapy, 14 (13.6%) were on typical antipsychotic monotherapy, 25 (24.3%) were taking depot antipsychotic medication and only 22 (21.4%) were receiving clozapine. Discussion As well as in other parts of the world, many TRS patients (78.6%) receive other drugs instead of clozapine in São Paulo, the best evidence-based medication for patients with TRS. The government should make every effort to provide medical training and the equipment and logistic support to adequately serve those who could benefit from clozapine treatment at the community health centers.

Enamel erosion and prevention efficacy characterized by confocal laser scanning microscope.

The aim of this study was to evaluate the erosion-inhibiting effect of two toothpastes on the development of erosion-like lesions, by a confocal laser scanning microscope (CLSM). Forty human enamel blocks were divided into five groups (n = 8), in accordance to evaluate the GC MI Paste Plus and Oral B with stannous fluoride, applied as slurries and associated with toothbrush. Specimens were submitted to an erosion challenge from citric acid (0.5%, pH = 2.8), for 5 min, six times a day, alternating in artificial saliva immersions. Reference group was not exposed to treatment. Part of specimens (Groups 02 and 03) was exposed twice daily just to slurries, for 2 min, therefore specimens from Groups 04 and 05 were also abraded, for 30 s. The enamel surfaces were morphological characterized using CLSM images, with mineral loss being measured using the resulting 3D images referenced to an un-challenged portion of the sample. Step values were compared using the one-way ANOVA test. CLSM was shown to be a viable, noncontact, and simple technique to characterize eroded surfaces. The statistical difference in the step size was significant between the groups (P = 0.001) and using multiple comparisons a statistically significant protective effect of toothpastes was shown when these were applied as slurries. Although groups submitted to tooth brush showed mineral loss similar to reference control group, due to the damages of abrasion associated.

Exercise prescription using the heart of claudication pain onset in patients with intermittent claudication.

OBJECTIVE: To assess the acute metabolic and cardiovascular responses to walking exercise at an intensity corresponding to the heart rate of claudication pain onset and to investigate the effects of a 12-week walking training program at this intensity on walking capacity. METHODS: Twenty-nine patients with intermittent claudication were randomly allocated to the walking training (n=17) or control (CO, n=12) group. The walking training group performed an acute exercise session comprising 15×2-min bouts of walking at the heart rate of claudication pain onset, with 2-min interpolated rest intervals. The claudication symptoms and cardiovascular and metabolic responses were evaluated. Walking training was then performed at the same intensity twice each week for 12 weeks, while the control group engaged in twice weekly stretching classes. The claudication onset distance and total walking distance were evaluated before and after the interventions. Brazilian Registry Clinical Trials: RBR-7M3D8W. RESULTS: During the acute exercise session, the heart rate was maintained within tight limits. The exercise intensity was above the anaerobic threshold and >80% of the heart rate peak and VO2peak. After the exercise training period, the walking exercise group (n=13) showed increased claudication onset distance (309±153 vs. 413±201m) and total walking distance (784±182 vs. 1,100±236m) compared to the control group (n=12) (p<0.05). CONCLUSION: Walking exercise prescribed at the heart rate of claudication pain onset enables patients with intermittent claudication to exercise with tolerable levels of pain and improves walking performance.

Exercise prescription using the heart of claudication pain onset in patients with intermittent claudication

OBJECTIVE: To assess the acute metabolic and cardiovascular responses to walking exercise at an intensity corresponding to the heart rate of claudication pain onset and to investigate the effects of a 12-week walking training program at this intensity on walking capacity. METHODS: Twenty-nine patients with intermittent claudication were randomly allocated to the walking training (n = 17) or control (CO, n = 12) group. The walking training group performed an acute exercise session comprising 15×2-min bouts of walking at the heart rate of claudication pain onset, with 2-min interpolated rest intervals. The claudication symptoms and cardiovascular and metabolic responses were evaluated. Walking training was then performed at the same intensity twice each week for 12 weeks, while the control group engaged in twice weekly stretching classes. The claudication onset distance and total walking distance were evaluated before and after the interventions. Brazilian Registry Clinical Trials: RBR-7M3D8W. RESULTS: During the acute exercise session, the heart rate was maintained within tight limits. The exercise intensity was above the anaerobic threshold and >80% of the heart rate peak and VO2peak. After the exercise training period, the walking exercise group (n = 13) showed increased claudication onset distance (309±153 vs. 413±201m) and total walking distance (784±182 vs. 1,100±236m) compared to the control group (n = 12) (p<0.05). CONCLUSION: Walking exercise prescribed at the heart rate of claudication pain onset enables patients with intermittent claudication to exercise with tolerable levels of pain and improves walking performance. .

Obesity and smoking: are they modulators of cough intravesical peak pressure in stress urinary incontinence?

PURPOSE: SUI (Stress Urinary Incontinence) results from sudden increases in intravesical peak pressures exceeding urethral resistance leading to involuntary urine loss. Obesity and smoking are well established reversible risk factors for SUI and may alter intravesical peak pressures. BMI, smoking status, and other clinical factors were studied to determine their relationship to CIPP (maximal Intravesical Peak Pressures generated by Cough) in SUI complaining women. MATERIALS AND METHODS: Three hundred nineteen women complaining of SUI were evaluated with medical history and urodynamics. Age, parity, comorbidities, previous surgery, BMI and history of smoking were obtained. The maximal intravesical peak pressures generated by cough (CIPP) and cough leak point pressure (CLPP) were acquired. Univariate and multivariate analysis were conducted. RESULTS: Current smokers and former smokers had similar CIPP (170cmH2O and 170cmH2O; p = 0.5, respectively); Those individuals who had never smoked had significantly lower CIPP (140cmH2O; p = 0.000 and p = 0.009 respectively). BMI was directly related to CIPP (r = 0.41; p = 0.000). Vaginal deliveries (r = -0.15, p = 0.08) and diabetes (r = 0.15, p = 0.016) were also directly related to CIPP on univariate analysis. Only smoking status (p = 0.000) and BMI (p = 0.000) were independently significantly related to CIPP on multivariate analysis. CONCLUSIONS: Obesity and smoking showed increased CIPP (maximal Intravesical Peak Pressures generated by Cough). While reduced BMI is related to lower CIPP, smoking cessation does not appear to diminish CIPP. These findings suggest that weight loss may reduce incontinence by CIPP modulation. However, the benefits of smoking cessation without additional lifestyle modification, may have no benefit to improve urinary incontinence.

Obesity and smoking: Are they modulators of cough intravesical peak pressure in stress urinary incontinence?

PURPOSE: SUI (Stress Urinary Incontinence) results from sudden increases in intravesical peak pressures exceeding urethral resistance leading to involuntary urine loss. Obesity and smoking are well established reversible risk factors for SUI and may alter intravesical peak pressures. BMI, smoking status, and other clinical factors were studied to determine their relationship to CIPP (maximal Intravesical Peak Pressures generated by Cough) in SUI complaining women. MATERIALS AND METHODS: Three hundred nineteen women complaining of SUI were evaluated with medical history and urodynamics. Age, parity, comorbidities, previous surgery, BMI and history of smoking were obtained. The maximal intravesical peak pressures generated by cough (CIPP) and cough leak point pressure (CLPP) were acquired. Univariate and multivariate analysis were conducted. RESULTS: Current smokers and former smokers had similar CIPP (170cmH2O and 170cmH2O; p = 0.5, respectively); Those individuals who had never smoked had significantly lower CIPP (140cmH2O; p = 0.000 and p = 0.009 respectively). BMI was directly related to CIPP (r = 0.41; p = 0.000). Vaginal deliveries (r = -0.15, p = 0.08) and diabetes (r = 0.15, p = 0.016) were also directly related to CIPP on univariate analysis. Only smoking status (p = 0.000) and BMI (p = 0.000) were independently significantly related to CIPP on multivariate analysis. CONCLUSIONS: Obesity and smoking showed increased CIPP (maximal Intravesical Peak Pressures generated by Cough). While reduced BMI is related to lower CIPP, smoking cessation does not appear to diminish CIPP. These findings suggest that weight loss may reduce incontinence by CIPP modulation. However, the benefits of smoking cessation without additional lifestyle modification, may have no benefit to improve urinary incontinence.

Influence of energy density of different light sources on Knoop hardness of a dual-cured resin cement.

The purpose of this study was to evaluate the Knoop hardness of a dual-cured resin-based luting cement irradiated with different light sources as well energy density through a ceramic sample. Three light-curing unit (LCUs) were tested: tungsten halogen light (HAL), light-emitting diode (LED) and xenon plasma-arc (PAC) lamp. Disc-shaped specimens were fabricated from a resin-based cement (Enforce). Three energy doses were used by modifying the irradiance (I) of each LCU and the irradiation time (T): 24 Jcm(-2) (I/2x2T), 24 Jcm(-2) (IxT) and 48 Jcm(-2) (Ix2T). Energy doses were applied through a 2.0-mm-thick ceramic sample (Duceram Plus). Three groups underwent direct irradiation over the resin cement with the different LCUs and a chemically-activated group served as a control. Thirteen groups were tested (n=10). Knoop hardness number (KHN) means were obtained from cross-sectional areas. Two-way ANOVA and the Holm-Sidak method were used for statistical comparisons of activation mode and energy doses (alpha=5%). Application of 48 J.cm(-2) energy dose through the ceramic using LED (50.5+/-2.8) and HAL (50.9+/-3.7) produced significantly higher KHN means (p<0.05) than the control (44.7+/-3.8). LED showed statistically similar performance to HAL. Only HAL showed a relationship between the increase of LCU energy dose and hardness increase.

Influence of energy density of different light sources on knoop hardness of a dual-cured resin cement

The purpose of this study was to evaluate the Knoop hardness of a dual-cured resin-based luting cement irradiated with different light sources as well energy density through a ceramic sample. Three light-curing unit (LCUs) were tested: tungsten halogen light (HAL), light-emitting diode (LED) and xenon plasma-arc (PAC) lamp. Disc-shaped specimens were fabricated from a resin-based cement (Enforce). Three energy doses were used by modifying the irradiance (I) of each LCU and the irradiation time (T): 24 Jcm-2 (I/2x2T), 24 Jcm-2 (IxT) and 48 Jcm-2 (Ix2T). Energy doses were applied through a 2.0-mm-thick ceramic sample (Duceram Plus). Three groups underwent direct irradiation over the resin cement with the different LCUs and a chemically-activated group served as a control. Thirteen groups were tested (n=10). Knoop hardness number (KHN) means were obtained from cross-sectional areas. Two-way ANOVA and the Holm-Sidak method were used for statistical comparisons of activation mode and energy doses (á=5%). Application of 48 J.cm-2 energy dose through the ceramic using LED (50.5±2.8) and HAL (50.9±3.7) produced significantly higher KHN means (p<0.05) than the control (44.7±3.8). LED showed statistically similar performance to HAL. Only HAL showed a relationship between the increase of LCU energy dose and hardness increase.

Building community partnerships: case studies of Community Advisory Boards at research sites in Peru, Zimbabwe, and Thailand.

BACKGROUND: Differences in resources, knowledge, and infrastructure between countries initiating and countries hosting HIV prevention research trials frequently yield ethical dilemmas. Community Advisory Boards (CABs) have emerged as one strategy for establishing partnerships between researchers and host communities to promote community consultation in socially sensitive research. PURPOSE: To understand the evolution of CABs and community partnerships at international research sites conducting HIV prevention trials. METHODS: Three research sites of the HIV Prevention Trials Network (HPTN) were selected to include geographical representation and diverse populations at risk for HIV/AIDS - in Lima, Peru; Chitungwiza, Zimbabwe; and Chiang Mai, Thailand. Data collection included review of secondary data, including academic publications and site-specific progress reports; observations at the research sites; face-to-face interviews with CAB members, research staff, and other key informants; and focus groups with study participants. Rapid assessment techniques were used for data analysis. RESULTS: Two of the three CABs developed new strategies for community representation in response to new studies. All three CABs expanded their original function and became advocates for broader community interests beyond HIV prevention. The participation and input of community representatives, in response to critical incidents that occurred at the sites over the past five years, helped to solidify partnerships between researchers and communities. LIMITATIONS: Rapid Assessment is an exploratory methodology designed to provide an understanding of a situation based on the integration of multiple data sources, collected within a short period of time, without a formal examination of transcribed and coded data. Case studies, as a method, are meant to draw out what can be learned from a single case but are not, in the scientific sense, generalizable. CONCLUSIONS: In developing countries, CABs can be dynamic entities that enhance the HIV research process, assist in responding to issues involving research ethics, and prepare communities for HIV research.

Can north american fish passage tools work for South american migratory fishes?

In North America, the Numerical Fish Surrogate (NFS) is used to design fish bypass systems for emigrating juvenile salmon as they migrate from hatchery outfalls and rearing habitats to adult habitat in the oceans. The NFS is constructed of three linked modules: 1) a computational fluid dynamics model describes the complex flow fields upstream of dams at a scale sufficiently resolved to analyze, understand and forecast fish movement, 2) a particle tracking model interpolates hydraulic information from the fixed nodes of the computational fluid model mesh to multiple locations relevant to migrating fish, and 3) a behavior model simulates the cognition and behavior of individual fish in response to the fluid dynamics predicted by the computational fluid dynamics model. These three modules together create a virtual reality where virtual fish exhibit realistic dam approach behaviors and can be counted at dam exits in ways similar to the real world. Once calibrated and validated with measured fish movement and passage data, the NFS can accurately predict fish passage proportions with sufficient precision to allow engineers to select one optimum alternative from among many competing structural or operational bypass alternatives. Although South American fish species are different from North American species, it is likely that the basic computational architecture and numerical methods of the NFS can be used for fish conservation in South America. Consequently, the extensive investment made in the creation of the NFS need not be duplicated in South America. However, its use in South America will require that the behavioral response of the continent's unique fishes to hydrodynamic cues must be described, codified and tested before the NFS can be used to conserve fishes by helping design efficient South American bypass systems. To this end, we identify studies that could be used to describe the movement behavior of South American fishes of sufficient...(AU)

Na América do Norte, o Numerical Fish Surrogate (NFS) é utilizado no projeto de sistemas de transposição de juvenis de salmão em seus deslocamentos dos habitats de desova e desenvolvimento inicial para o de adultos, no oceano. O NFS é estruturado em três módulos interconectados: 1) um modelo computacional de dinâmica de fluidos (CFD) que descreve o complexo escoamento acima da barragem em uma escala suficientemente apropriada para analisar, entender e prever os movimentos dos peixes, 2) um modelo de rastreamento de partículas que interpola informações hidráulicas dos nós da malha do modelo computacional para localizações múltiplas relevantes ao peixe em migração, 3) um modelo comportamental que simula o conhecimento e o comportamento de cada peixe em resposta à dinâmica do escoamento predita pelo modelo computacional. Esses três módulos juntos criam uma realidade virtual onde peixes virtuais exibem um comportamento realístico de aproximação da barragem e podem ser contados de uma forma similar a do mundo real. Uma vez calibrado e validado com medições do movimento dos peixes e dados de passagem, o NFS pode predizer acuradamente a proporção de passagem de peixes, com suficiente precisão para permitir que engenheiros selecionem uma alternativa ótima dentre as várias opções estruturais e operacionais. Embora as espécies de peixes Sul Americanas sejam diferentes das espécies da América do Norte, é provável que a arquitetura computacional básica e os métodos numéricos do NFS possam ser usados para a conservação de peixes na América do Sul. Consequentemente, o grande investimento feito na criação do NFS não precisa ser repetido na América do Sul. Contudo, seu uso na América do Sul exigirá que a resposta comportamental dessa fauna aos sinais hidrodinâmicos seja descrita, codificada e testada antes que o NFS possa ser usado na conservação de peixes pelo seu emprego na projeção de sistemas de transposição eficientes. Nesse contexto, o presente...(AU)

Is fish passage technology saving fish resources in the lower La Plata River basin?

Over 450 dams have been constructed in the upper Paraná River basin in Brazil during the past 40 years. River regulation by these dams is considered a primary factor in the reduction of fish diversity and depletion of migratory species. In contrast to the upper Paraná Basin, only two large dams (both with upstream fish passage) have been constructed in the lower La Plata River basin. Fishery managers in the lower basin are concerned that existing and planned dams will further deplete populations of migratory fish species that constitute important recreational and commercial fisheries as has occurred in the upper basin. We assessed the sustainability of fisheries in the lower basin in the face of increased river regulation by using literature information to describe the efficiency of the fish passage systems used to mitigate river regulation impacts on fisheries. Our analysis shows that fish passage systems at both lower basin dams, Yacyreta and Salto Grande, fail to transfer sufficient numbers of upstream migrants to sustain populations of migratory species. Fish passage efficiency of target species in the fish elevators at Yacyreta is less than 2 percent. Fish diversity in the fish elevators is low because about 85 percent of the fish belong to only three non-migratory species (Pimelodus maculatus, Oxydoras kneri and Rhinodoras dorbignyi). Large migratory species targeted for passage rarely comprise even 5 percent of the fish number in the passage system. The two Borland locks at Salto Grande Dam cannot dependably pass large numbers of migratory species because passage efficiency is dependent upon interactions of powerhouse and spillway operation with tailrace elevations. Most species in the Borland system were either a small catfish (Parapimelodus valenciennis) or a engraulid (Lycengraulis grossidens). Again, the targeted migratory species were not abundant in the passage system. We conclude that existing fish passage technology in...(AU)

Mais de 450 barragens foram construídas no alto rio Paraná, Brasil, nos últimos 40 anos. A regulação dos rios por barragens é considerada um dos fatores primários de redução da diversidade de peixes e depleção de espécies migratórias. Em contraste, somente duas grandes barragens foram construídas nos trechos mais inferiores da bacia do rio da Prata. No momento, há uma grande preocupação acerca do impacto dos represamentos sobre espécies que se constituem a base da pesca comercial e esportiva na bacia. Este artigo aborda o desempenho das passagens de peixes das barragens de Yacyreta e Salto Grande, monstrando que as mesmas falham na transferência de grandes quantidades de espécies migratórias para os trechos a montante. A barragem de Yacyreta tem dois elevadores com problemas importantes de projeto. Como resultado, a eficiência na passagem das espécies-alvo é menor do que 2 por cento. A diversidade das espécies transferidas é baixa, uma vez que 85 por cento dos espécimes dominantes nos elevadores foram representadas por uma espécie de Pimelodidae (Pimelodus maculatus) e duas de Doradidae (Oxydoras kneri e Rhinodoras dorbignyi). A passagem de grandes espécies alvo migratórias raramente compreende até 5 por cento do número de peixes no sistema de passagem. A barragem de Salto Grande tem duas passagens do tipo eclusas de Borland linstaladas, cuja performance varia consideravelmente dependendo da operação da casa de força e dos vertedouros, bem como da elevação de nível no canal de fuga. A maioria dos espécimes que passam pertencem a uma pequena espécie de Pimelodidae (Parapimelodus valenciennis) e a uma espécie de Engraulidae (Lycengraulis grossidens). Um novo direcionamento no desenho de passagens de peixes é necessário para a preservação das espécies migratórias em rios Sul Americanos. Informações integradas de geomorfologia (habitat), atratores de natureza hidrodinâmica detectável pelos peixes para selecionar as rotas de migração ascendentes...(AU)

Is fish passage technology saving fish resources in the lower La Plata River basin?

Over 450 dams have been constructed in the upper Paraná River basin in Brazil during the past 40 years. River regulation by these dams is considered a primary factor in the reduction of fish diversity and depletion of migratory species. In contrast to the upper Paraná Basin, only two large dams (both with upstream fish passage) have been constructed in the lower La Plata River basin. Fishery managers in the lower basin are concerned that existing and planned dams will further deplete populations of migratory fish species that constitute important recreational and commercial fisheries as has occurred in the upper basin. We assessed the sustainability of fisheries in the lower basin in the face of increased river regulation by using literature information to describe the efficiency of the fish passage systems used to mitigate river regulation impacts on fisheries. Our analysis shows that fish passage systems at both lower basin dams, Yacyreta and Salto Grande, fail to transfer sufficient numbers of upstream migrants to sustain populations of migratory species. Fish passage efficiency of target species in the fish elevators at Yacyreta is less than 2 percent. Fish diversity in the fish elevators is low because about 85 percent of the fish belong to only three non-migratory species (Pimelodus maculatus, Oxydoras kneri and Rhinodoras dorbignyi). Large migratory species targeted for passage rarely comprise even 5 percent of the fish number in the passage system. The two Borland locks at Salto Grande Dam cannot dependably pass large numbers of migratory species because passage efficiency is dependent upon interactions of powerhouse and spillway operation with tailrace elevations. Most species in the Borland system were either a small catfish (Parapimelodus valenciennis) or a engraulid (Lycengraulis grossidens). Again, the targeted migratory species were not abundant in the passage system. We conclude that existing fish passage technology in...

Mais de 450 barragens foram construídas no alto rio Paraná, Brasil, nos últimos 40 anos. A regulação dos rios por barragens é considerada um dos fatores primários de redução da diversidade de peixes e depleção de espécies migratórias. Em contraste, somente duas grandes barragens foram construídas nos trechos mais inferiores da bacia do rio da Prata. No momento, há uma grande preocupação acerca do impacto dos represamentos sobre espécies que se constituem a base da pesca comercial e esportiva na bacia. Este artigo aborda o desempenho das passagens de peixes das barragens de Yacyreta e Salto Grande, monstrando que as mesmas falham na transferência de grandes quantidades de espécies migratórias para os trechos a montante. A barragem de Yacyreta tem dois elevadores com problemas importantes de projeto. Como resultado, a eficiência na passagem das espécies-alvo é menor do que 2 por cento. A diversidade das espécies transferidas é baixa, uma vez que 85 por cento dos espécimes dominantes nos elevadores foram representadas por uma espécie de Pimelodidae (Pimelodus maculatus) e duas de Doradidae (Oxydoras kneri e Rhinodoras dorbignyi). A passagem de grandes espécies alvo migratórias raramente compreende até 5 por cento do número de peixes no sistema de passagem. A barragem de Salto Grande tem duas passagens do tipo eclusas de Borland linstaladas, cuja performance varia consideravelmente dependendo da operação da casa de força e dos vertedouros, bem como da elevação de nível no canal de fuga. A maioria dos espécimes que passam pertencem a uma pequena espécie de Pimelodidae (Parapimelodus valenciennis) e a uma espécie de Engraulidae (Lycengraulis grossidens). Um novo direcionamento no desenho de passagens de peixes é necessário para a preservação das espécies migratórias em rios Sul Americanos. Informações integradas de geomorfologia (habitat), atratores de natureza hidrodinâmica detectável pelos peixes para selecionar as rotas de migração ascendentes...