Application of approximation theory by nonlinear manifolds in Sturm-Liouville inverse problems

We give here some negative results in Sturm-Liouville inverse theory, meaning that we cannot approach any of the potentials with $m+1$ integrable derivatives on $\mathbb{R}^+$ by an $\omega$-parametric analytic family better than order of $(\omega\ln\omega)^{-(m+1)}$. Next, we prove an estimation of the eigenvalues and characteristic values of a Sturm-Liouville operator and some properties of the solution of a certain integral equation. This allows us to deduce from [Henkin-Novikova] some positive results about the best reconstruction formula by giving an almost optimal formula of order of $\omega^{-m}$.Comment: 40 page

Patagonotothen ramsayi

This species has a relatively small range on the continental shelf and slope of the southern part of the Patagonia Sea where it plays an important ecological role as a prey item for larger marine species. The majority of its global population is concentrated in southern Argentina, including the Malvinas Islands, where the main fishing ground is located. One generation length is estimated as 10 years. It is relatively slow-growing and late to maturity with relatively low fecundity, which may cause it to be susceptible to declines when facing heavy fishing pressure. Previous to 2006, it was mostly discarded as bycatch in large quantities beginning in the 1980s. A large-scale, commercial fishery began in 2007 in the Malvinas area. In areas outside the Malvinas closer to the Argentine mainland, it is taken in fisheries in relatively small amounts. According to stock assessment models based on catch per unit effort data and fishery independent trawl surveys, the estimated biomass for the period of 2005 to 2018 was highest in 2005 and then declined by 79% to a low in 2018. According to the 2019 and 2020 survey results, biomass has continued to decline. Biomass trends prior to 2005 are poorly understood, but based on these data, it is suspected that its population has declined by 40-50% on a global-level over the past one and a half generation lengths, or 15 years. In addition, declines in length at maturity and average length of individuals in the survey catch have also occurred. The cause of decline is poorly understood, but may be attributed in part to fishing activity or a shift in the spatial distribution of its abundance to areas adjacent to the Malvinas. Several fishery management measures are in place, catches have been at a relatively low level and it is not considered overfished. Due to the uncertainty associated with the cause of decline and lack of data prior to 2005, it is not possible to estimate the population trend to cover a three generation length period (either in the past or into the future) at this time. It is listed as Data Deficient with a strong recommendation to conduct studies to improve the understanding of this decline both within the Malvinas area and areas adjacent to it.Fil: Buratti, C.. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Díaz de Astarloa, Juan Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Hüne, M.. Universidad Austral de Chile; ChileFil: Irigoyen, A.. No especifíca;Fil: Landaeta, M.. Universidad de Valparaíso; ChileFil: Riestra, C.. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Vieira, J. P.. Universidade Federal Do Rio Grande.; Brasi

Paralichthys isosceles

This demersal species occurs from southern Brazil to Argentina and is taken in multi-species commercial´s fisheries that target demersal fishes through much of its range. It is a relatively minor component of the catch of Paralichthys species as compared to catch of the sympatric P. patagonicus. For purposes of this assessment, half of the global population is considered to occur in Brazil and the other half in Uruguay and Argentina. According to landings and catch per unit effort data, the demersal fish stocks of Brazil are inferred to have declined by at least 30% and possibly to 50%. Due to the lack of specific data for this species, an estimate for population decline is not available or cannot be suspected at this time. According to stock assessment and fisheries data, there is no decline detected in the demersal stock in Argentina and Uruguay and abundance indices show an increase in recent years (since 2014). Fishing effort continues at an unsustainable level in Brazil, the fishery is not well-monitored and conservation measures are insufficient. Conservation measures in Argentina and Uruguay include a total allowable catch limit and regular monitoring of stock status. Based on the potential major threat from overfishing in at least half of its global population, but lack of quantified data, it is listed as Data Deficient with a recommendation to improve fisheries monitoring, including the collection of species-specific data, as" "well as implement conservation measures to reduce effort in Brazilian fisheries.Fil: Riestra, C.. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Díaz de Astarloa, Juan Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Vieira, J. P.. Universidade Federal do Rio Grande do Sul; BrasilFil: Buratti, C.. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Irigoyen, A.. No especifíca;Fil: Landaeta, M.. Universidad de Valparaíso; ChileFil: Hüne, M.. Universidad Austral de Chile; Chil

Cottoperca trigloides, Frogmouth

This widely distributed, demersal species is associated with rocky bottoms and kelp forests. It is discarded as bycatch in trawl fisheries, but this is not expected to be driving population declines approaching a Near Threatened or threatened level at this time; therefore, it is listed as Least Concern.Fil: Buratti, C.. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Díaz de Astarloa, Juan Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Hüne, M.. Universidad Austral de Chile; ChileFil: Irigoyen, A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Landaeta, M.. Universidad de Valparaíso; ChileFil: Riestra, C.. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Vieira, J. P.. Universidade Federal Do Rio Grande.; Brasi

Strongyloides stercoralis: a rare and severe presentation in a pregnant woman

Strongyloides stercoralis is a parasitic nematode with a worldwide distribution. It can go from an asymptomatic infection to a life-threatening hyperinfection syndrome. Here, we report a case of intestinal obstruction due to S. stercoralis in a pregnant woman. This condition, as well as severe strongyloidiasis in pregnant women, is seldomly reported. In this case, Human T-lymphotropic Virus 1 (HTLV-1) coinfection was confirmed, a well-known risk factor for a more severe presentation of strongyloidiasis. We suggest that HTLV status should be screened in every severe S. stercoralis infection, or when, despite a correct treatment, a relapse is observed

Sebastes oculatus, Patagonian Rockfish

This demersal, reef-associated species is common and abundant through much of its range. It is taken in fisheries at relatively low levels and may be impacted by invasive salmon. Global-level declines are not considered to be approaching a Near Threatened or threatened level at this time; therefore, it is listed as Least Concern.Fil: Buratti, C.. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Díaz de Astarloa, Juan Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Hüne, M.. Universidad Austral de Chile; ChileFil: Irigoyen, Alejo Joaquin. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Landaeta, M.. Universidad de Valparaíso; ChileFil: Riestra, C.. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Vieira, J. P.. Universidade Federal Do Rio Grande.; Brasi

Acanthistius patachonicus, Patagonian Grouper

This rocky reef species has a relatively small range from southern Brazil to central Argentina. It is long- lived and the estimated generation length is 28.5 years. Large commercial fisheries targeted spawning aggregations of this species in the 1980s and 1990s until abundance steeply declined to the point where the market was no longer viable and at least four large areas where spawning aggregations were heavily depleted. Currently, it continues to be targeted by artisanal and industrial fisheries. The implementation of effective fishing area closures, both permanent and seasonal, in the El Rincón area is considered to provide a high level of protection for half of the global population of this species. According to fisher interviews, some level of population decline occurred within the past 40 years, or over a little more than one generation length ago. The lack of fisheries data, including a stock assessment, and the low level of understanding of the status of historical and current spawning aggregations prevents the estimation of percent population decline at this time. A secondary threat may be the reduction of habitat quality due to the invasive alga Undaria pinnatifida on shallow reefs, which has spread through much of its range. It is listed as Data Deficient with a strong recommendation to improve fishery monitoring and to conduct studies on spawning aggregations.Fil: Irigoyen, Alejo Joaquin. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Riestra, C.. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Buratti, C.. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Díaz de Astarloa, Juan Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Hüne, M.. Universidad Austral de Chile; ChileFil: Landaeta, M.. Universidad de Valparaíso; ChileFil: Vieira, J. P.. Universidade Federal Do Rio Grande.; Brasi

Paralichthys patagonicus

This demersal species occurs from southern Brazil to northern Argentina and is taken in multi-speciescommercial fisheries that target demersal fishes through much of its range. For purposes of thisassessment, half of the global population is considered to occur in Brazil and the other half in Uruguayand Argentina. According to landings and catch per unit effort data, the population in Brazil isoverexploited and declined by at least 30-60% over the past three generation lengths, or about a 30-year time period. According to stock assessment and fisheries data, there is no decline detected in thedemersal fish stock in Argentina and Uruguay and abundance indices show an increase in recent years(since 2014). Fishing effort continues at an unsustainable level in Brazil, the fishery is not well-monitoredand conservation measures are insufficient. Conservation measures in Argentina and Uruguay include atotal allowable catch limit and regular monitoring of stock status. In addition to fishing, this species isexposed to pollution in estuaries that may be impacting the survivability of some individuals. Based ondeclines in half of its global population (Brazil), at least a 30% global-level decline is suspected to haveoccurred over the past three generation lengths; therefore, it is listed as Vulnerable A2bcd. It isrecommended to improve fisheries monitoring, including the collection of species-specific data, as wellas implement conservation measures to reduce effort in Brazilian fisheries.Fil: Riestra, Cecilia Micaela. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Díaz de Astarloa, Juan Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Vieira, J. P.. Universidade Federal Do Rio Grande.; BrasilFil: Buratti, C.. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Irigoyen, A.. No especifíca;Fil: Landaeta, M.. Universidad de Valparaíso; ChileFil: Hune, M.. Fundación Ictiológica de Chile; Chil

A resolved study of the inner regions of nearby galaxies with an excess of young massive stars: missing link in the AGN–starburst connection?

We have selected galaxies with very high levels of H α emission (EQW(H α) >700 Å.) in their central regions from the final data release of the MaNGA survey. Our study focuses on 14 very well-resolved nearby galaxies with stellar masses in the range 9.5 < log M*/(M⊙) < 11.5. We investigate a variety of procedures for selecting galaxy regions that are likely to harbour excess populations of young massive stars, finding that selection in the 2D space of extinction-corrected H α EQW and [S III]/[S II] line ratio produces the best results. By comparing stacked spectra covering these regions with stacked spectra covering normal starburst regions with 100 Å<EQW(H α) <200 Å, we obtain the following main results: (1) Clear signatures of excess Wolf–Rayet stars are found in half of the H α excess regions, (2) galaxy regions containing excess Wolf–Rayet stars are more often associated with the presence of high-ionization emission lines characteristic of accreting black holes. Excess [Ne III] is detected in 4 out of 8 of the WR regions and there are tentative [Fe X] detections in 2 galaxies. (3) Regions of the galaxy with excess Wolf–Rayet stars are located where the interstellar medium has larger ionized gas turbulent velocities and higher neutral gas overdensities. We make a first attempt to constrain changes in the high-mass end of the stellar initial mass function (IMF) using the HR-pyPopStar evolutionary population synthesis models that include high-wavelength-resolution theoretical atmosphere libraries for Wolf–Rayet stars

Sprattus fuegensis, Fuegian Sprat

This coastal, pelagic species is widely distributed in the southwestern Atlantic and southeastern Pacific. It is short-lived and has an estimated generation length of 3-4 years. It is targeted by commercial, artisanal fisheries in the northern part of its range in Chile. Total biomass has declined by about 40% over the past three generation lengths, or since 2006, in the Lakes Region of Chile, and that stock is considered overfished. However, it is not targeted elsewhere in its range at this time, including in the area that contains the largest proportion of its global population. Fishing activity is not expected to be driving global-level declines approaching a Near Threatened or threatened level at this time; therefore, it is listed as Least Concern. However, fishing effort may expand further south where it remains abundant, and this is a concern.Fil: Buratti, C.. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Díaz de Astarloa, Juan Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Hüne, M.. Universidad Austral de Chile; ChileFil: Irigoyen, Alejo Joaquin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Landaeta, M.. Universidad de Valparaíso; ChileFil: Riestra, C.. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Vieira, J. P.. Universidade Federal Do Rio Grande.; BrasilFil: Di Dario, F.. Universidade Federal do Estado do Rio de Janeiro; Brasi