Bounding the ground-state energy of a many-body system with the differential method

This paper promotes the differential method as a new fruitful strategy for estimating a ground-state energy of a many-body system. The case of an arbitrary number of attractive Coulombian particles is specifically studied and we make some favorable comparison of the differential method to the existing approaches that rely on variational principles. A bird's-eye view of the treatment of more general interactions is also given.Comment: version 1->2 (main revisions): subsection 2.2, equation (18), footnote 6 have been adde

Sustainable wildlife extraction and the impacts of socio-economic change among the Kukama-Kukamilla people of the Pacaya-Samiria National Reserve, Peru

Throughout the tropics, hunting and fishing are critical livelihood activities for many Indigenous peoples. However, these practices may not be sustainable following recent socio-economic changes in Indigenous populations. To understand how human population growth and increased market integration affect hunting and fishing patterns, we conducted semi-structured interviews in five Kukama-Kukamilla communities living along the boundary of the Pacaya-Samiria National Reserve, in the Peruvian Amazon. Extrapolated annual harvest rates of fish and game species by these communities amounted to 1,740 t and 4,275 individuals (67 t), respectively. At least 23 fish and 27 game species were harvested. We found a positive correlation between village size and annual community-level harvest rates of fish and a negative relationship between market exposure and mean per-capita harvest rates of fish. Catch-per-unit-effort (CPUE) analyses indicated local depletion of fish populations around larger, more commercial communities. Catch-per-unit-effort of fish was lower in more commercial communities and fishers from the largest village travelled further into the Reserve, where CPUE was higher. We found no effect of village size or market exposure on harvest rates or CPUE of game species. However, larger, more commercial communities targeted larger, economically valuable species. This study provides evidence that human population growth and market-driven hunting and fishing pose a growing threat to wildlife and Indigenous livelihoods through increased harvest rates and selective harvesting of species vulnerable to exploitation

Reconocimiento del lenguaje de señas mediante aprendizaje automático para niños de primaria

For most people, hand gestures are used to demonstrate expressiveness for people with hearing disabilities. This manual representation of symbols constitutes a language. A system that recognizes Panamanian sign language that is oriented towards children with hearing disabilities is relevant to a more fluid and effective learning. For development, artificial intelligence tools should be used, such as machine learning, image processing and classifier, as well as the use of a digital camera to capture gestures expressed by hands. As an objective, this system will only recognize the vowels of the alphabet (a, e, i, o, u) in text as a start and test stage.Los gestos de las manos son utilizados para demostrar expresividad, un punto mucho más importante para personas con discapacidad auditiva, quienes utilizan esta representación de símbolos manualmente como lenguaje. Un sistema que reconozca el lenguaje de señas panameño que esté orientado hacia niños con discapacidades auditivas es relevante para un aprendizaje más fluido y efectivo. Para el desarrollo, se deberán usar herramientas de inteligencia artificial, como aprendizaje automático, procesador y clasificador de imágenes, además del uso de una cámara digital para capturar los gestos expresados con las manos. Como objetivo, este sistema solamente reconocerá las vocales del alfabeto (a, e, i, o, u) en texto como etapa de inicio y prueba

LA IMPORTANCIA DE LA PARTICIPACION COMUNITARIA EN LOS PLANES DE MANEJO DE FAUNA SILVESTRE EN EL NOR ORIENTE DEL PERU

En este documento se analizan las acciones de manejo de fauna silvestre con participación comunitaria realizadas tanto en la Reserva Comunal Tamshiyacu - Tahuayo (RCTT) como en la Reserva Nacional Pacaya Samiria (RNPS), nor-oriente del Perú. El objetivo fue determinar métodos para obtener y analizar información biológica con participación comunitaria. Las áreas de estudio comprendieron: 1) el área del Tahuayo-Blanco, en la RCTT, 2) el área del canal de Puinahua, en la RNPS y 3) el área del Samiria-Marañón, en la RNPS. La información fue obtenida con ayuda de cazadores locales, denominados localmente como inspectores, en el caso de la RCTT y como expertos, en el caso de la RNPS. Esta información incluyó número de cazadores, especies cazadas, tiempo de captura, campamentos utilizados, tiempo de residenciay accesibilidad a los sitios de caza. Consideramos una necesidad realizarinvestigaciones para mejorar el sistema de co-manejo; asimismo, la metodología descrita en este estudio puede ser utilizada también para la pesca y forestería. Una recomendación es incorporar el análisis de fauna silvestre realizado por las comunidades locales. Adicionalmente, el manejo debe tomar en consideración la zonificación de las áreas de caza, rotación de la caza y una reducción de las cosechas no sostenibles. El manejo de fauna silvestre con participación comunitaria requiere de consideraciones políticas que involucren acciones tendientes al mejoramiento del hábitat y al empoderamiento de las comunidades locales en las áreas de co-manejo

Wild meat trade over the last 45 years in the Peruvian Amazon

The trade in wild meat is an important economic component of rural people's livelihoods, but it has been perceived to be among the main causes of the decline of wildlife species. Recently, the COVID-19 pandemic has brought to light an additional concern of wildlife markets as a major human-health challenge. We analyzed data from the largest longitudinal monitoring (1973–2018) of the most important urban wild-meat markets in Iquitos, Peru, to examine the trends in and impacts of these markets on people's livelihoods. Over the last 45 years, wild meat sales increased at a rate of 6.4 t/year (SD 2.17), paralleling urban population growth. Wild meat sales were highest in 2018 (442 t), contributing US$2.6 million (0.76%) to the regional gross domestic product. Five species of ungulates and rodents accounted for 88.5% of the amount of biomass traded. Vulnerable and Endangered species represented 7.0% and 0.4% of individuals sold, respectively. Despite growth in sales, the contribution of wild meat to overall urban diet was constant: 1–2%/year of total meat consumed. This result was due to greater availability and higher consumption of cheaper meats (e.g., in 2018, poultry was 45.8% cheaper and was the most consumed meat) coupled with the lack of economic incentives to harvest wild meat species in rural areas. Most wild meat was sold salted or smoked, reducing the likelihood of foodborne diseases. Community-based wildlife management plans and the continued trade bans on primates and threatened taxa may avoid biodiversity loss. Considering the recent COVID-19 pandemic, future management plans should include potential viral hosts and regulation and enforcement of hygiene practices in wild-meat markets

Evidence for directional selection at a novel major histocompatibility class I marker in wild common frogs (Rana temporaria) exposed to a viral pathogen (Ranavirus).

(c) 2009 Teacher et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Whilst the Major Histocompatibility Complex (MHC) is well characterized in the anuran Xenopus, this region has not previously been studied in another popular model species, the common frog (Rana temporaria). Nor, to date, have there been any studies of MHC in wild amphibian host-pathogen systems. We characterise an MHC class I locus in the common frog, and present primers to amplify both the whole region, and specifically the antigen binding region. As no more than two expressed haplotypes were found in over 400 clones from 66 individuals, it is likely that there is a single class I locus in this species. This finding is consistent with the single class I locus in Xenopus, but contrasts with the multiple loci identified in axolotls, providing evidence that the diversification of MHC class I into multiple loci likely occurred after the Caudata/Anura divergence (approximately 350 million years ago) but before the Ranidae/Pipidae divergence (approximately 230 mya). We use this locus to compare wild populations of common frogs that have been infected with a viral pathogen (Ranavirus) with those that have no history of infection. We demonstrate that certain MHC supertypes are associated with infection status (even after accounting for shared ancestry), and that the diseased populations have more similar supertype frequencies (lower F(ST)) than the uninfected. These patterns were not seen in a suite of putatively neutral microsatellite loci. We interpret this pattern at the MHC locus to indicate that the disease has imposed selection for particular haplotypes, and hence that common frogs may be adapting to the presence of Ranavirus, which currently kills tens of thousands of amphibians in the UK each year

Assessing the Minimum Sampling Effort Required to Reliably Monitor Wild Meat Trade in Urban Markets

The trade of wild meat generates great economic returns for local communities but at a cost of increasing harvest rates of game species. Monitoring wild meat trade in urban markets is a low-cost method that can be employed to assess impacts of hunting on game populations. Nevertheless, wild meat markets are complex systems to monitor since they often vary over time, are illegal in some countries, and often vendors distrust researchers. We investigated the wild meat trade in the Belén market in Iquitos, Peru, the largest wild meat market in the Amazon, to estimate the minimum sampling effort required to obtain reliable estimates of the amounts and prices of wild meat sold. During two 12-month surveys (Sept. 2006–Aug. 2007, Sept. 2017–Aug. 2018), we conducted a total of 4,524 vendor interviews in 320 sample days. By modeling 10 possible scenarios in which sampling size and amount of meat traded varied, we calculated the accuracy and precision of different survey protocols. We found that in scenarios where the daily amount of wild meat on sale was between 40 and 650 kg, a sampling effort equal to or >2 sampling days per month provided good accuracy (>90%) and precision (>85%). However, in scenarios where wild meat traded was less frequent, or for rarer species, an effort of at least one interview per week is required. Vendor declaration of the daily amounts of meat sold was similar to the quantity on sale (accuracy = 98%), suggesting that sellers are aware of the volume of wild meat brought to market. To accurately monitor the trade of wild meat in urban markets, we recommend a minimum sampling effort, ranging from two interviews per week to two interviews per month, depending on the amount of wild meat traded; in other occasions, a punctual interview on meat sellers' perception may also be useful

Patterns of genomic change in residual disease after neoadjuvant chemotherapy for estrogen receptor-positive and HER2-negative breast cancer

Background: Treatment of patients with residual disease after neoadjuvant chemotherapy for breast cancer is an unmet clinical need. We hypothesised that tumour subclones showing expansion in residual disease after chemotherapy would contain mutations conferring drug resistance. Methods: We studied oestrogen receptor and/or progesterone receptor-positive, HER2-negative tumours from 42 patients in the EORTC 10994/BIG 00-01 trial who failed to achieve a pathological complete response. Genes commonly mutated in breast cancer were sequenced in pre and post-treatment samples. Results: Oncogenic driver mutations were commonest in PIK3CA (38% of tumours), GATA3 (29%), CDH1 (17%), TP53 (17%) and CBFB (12%); and amplification was commonest for CCND1 (26% of tumours) and FGFR1 (26%). The variant allele fraction frequently changed after treatment, indicating that subclones had expanded and contracted, but there were changes in both directions for all of the commonly mutated genes. Conclusions: We found no evidence that expansion of clones containing recurrent oncogenic driver mutations is responsible for resistance to neoadjuvant chemotherapy. The persistence of classic oncogenic mutations in pathways for which targeted therapies are now available highlights their importance as drug targets in patients who have failed chemotherapy but provides no support for a direct role of driver oncogenes in resistance to chemotherapy. ClinicalTrials.gov: EORTC 10994/BIG 1-00 Trial registration number NCT00017095.SCOPUS: ar.jDecretOANoAutActifinfo:eu-repo/semantics/publishe