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1.
An Sist Sanit Navar ; 47(1)2024 Mar 07.
Artigo em Espanhol | MEDLINE | ID: mdl-38451043

RESUMO

Catamenial pneumothorax is a spontaneous recurrent pneumothorax that occurs in women of reproductive age and in temporal relationship with the menses. It usually occurs within 24 hours before or 72 hours after the start of the menstrual cycle; however, multiple variations have been described in terms of the temporal relationship. To date, it is considered a rare condition; this may be justified by the limited available knowledge on this disease leading to misdiagnosis. Often, making a diagnosis of catamenial pneumothorax is complicated; it mainly depends on the medical history; also, it may be a surgical or histopathological diagnosis. Management strategies for catamenial pneumothorax may include combinations of hormonal therapy, pleurodesis, lung parenchyma resection, and diaphragm resection/repair. The aim of reporting this atypical case of catamenial pneumothorax is to highlight the relevance of having the adequate knowledge on this entity so it does not go unnoticed despite its apparent low incidence.


Assuntos
Pneumotórax , Humanos , Feminino , Pneumotórax/terapia , Doenças Raras
2.
Ecol Evol ; 14(2): e10879, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38343567

RESUMO

Stingless bees are important pollinators in tropical forests. Yet, we know little about their foraging behavior (e.g., their nutritional requirements or their floral sources visited for resource collection). Many stingless bees not only depend vitally on pollen and nectar for food but also on resin for nest building and/or defense. However, it is unclear whether the large effort devoted to collecting resin as a non-food resource by certain stingless bees affects their foraging behavior. Therefore, in this study, we analyzed differences in foraging patterns (i.e., foraging activity, proportion of collected resources, and specialization in plants visited) and resource nutritional composition (i.e., sucrose amount in nectar and amino acids in pollen) of seven different stingless bee species (eleven wild colonies) in north-western Ecuador with a particular focus on the role of resin collection. We found that species with a high resin intake tended to be more active than species with a low resin intake. The foragers per minute invested for pollen collection were similar across all species. Sucrose intake per minute differed between some species but was not affected by increased resin intake. Interestingly, high and low resin collectors partly differed in the plants visited for pollen collection. Pollen amino acid profiles largely, but not completely, overlapped between the two resin collection groups. Our findings show that the foraging patterns and plant choices of stingless bees may vary depending on their resin intake, highlighting the need for more research focusing on resin collection and use by stingless bees.


Las abejas sin aguijón son polinizadores importantes en los bosques tropicales. Sin embargo, sabemos poco acerca de su comportamiento de forrajeo (e.g., sus requisitos nutricionales o las fuentes florales visitadas para la recolección de recursos). Muchas abejas sin aguijón dependen vitalmente no solo de polen y de néctar como alimento, sino también de resinas para la construcción de su nido y/o defensa. Sin embargo, no está claro si el gran esfuerzo dedicado a la recolección de resina como recurso no alimentario de ciertas abejas sin aguijón afecta su comportamiento de forrajeo. Por lo tanto, en este estudio, analizamos las diferencias en los patrones de forrajeo (i.e., actividad de forrajeo, proporción de recursos recolectados y especialización en las plantas visitadas) y la composición nutricional de los recursos recolectados (i.e., cantidad de sacarosa en el néctar y de aminoácidos en el polen) de siete especies diferentes de abejas sin aguijón (once colonias silvestres) en el noroeste de Ecuador, con un enfoque particular en el rol de la recolección de resina. Encontramos que las especies con una recolección alta de resina tienden a ser más activas que las especies con una recolección baja de resina. La cantidad de forrajeadores por minuto dedicada a la recolección de polen fue similar en todas las especies. La ingesta de sacarosa por minuto difirió entre algunas especies, pero no se vio afectada por un aumento en la recolección de resina. Interesantemente, las abejas con una recolección alta y baja de resina difirieron parcialmente en las plantas que visitaron para la recolección de polen. Entre los dos grupos de recolección de resina también hubo diferencias con respecto al perfil de aminoácidos en el polen que recolectaron. El perfil de aminoácidos se sobrelapaba, pero no completamente, entre los dos grupos. Nuestros resultados muestran que los patrones de forrajeo y las elecciones de plantas de las abejas sin aguijón pueden variar según su consumo de resina, destacando la necesidad de hacer más investigaciones centradas en la recolección y el uso de resina por parte de las abejas sin aguijón.

5.
Sci Data ; 10(1): 916, 2023 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-38123598

RESUMO

Type 1 diabetes mellitus (T1D) patients face daily difficulties in keeping their blood glucose levels within appropriate ranges. Several techniques and devices, such as flash glucose meters, have been developed to help T1D patients improve their quality of life. Most recently, the data collected via these devices is being used to train advanced artificial intelligence models to characterize the evolution of the disease and support its management. Data scarcity is the main challenge for generating these models, as most works use private or artificially generated datasets. For this reason, this work presents T1DiabetesGranada, an open under specific permission longitudinal dataset that not only provides continuous glucose levels, but also patient demographic and clinical information. The dataset includes 257 780 days of measurements spanning four years from 736 T1D patients from the province of Granada, Spain. This dataset advances beyond the state of the art as one the longest and largest open datasets of continuous glucose measurements, thus boosting the development of new artificial intelligence models for glucose level characterization and prediction.


Assuntos
Diabetes Mellitus Tipo 1 , Humanos , Inteligência Artificial , Glicemia , Automonitorização da Glicemia/métodos , Glucose , Qualidade de Vida
7.
PNAS Nexus ; 2(1): pgac283, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36712929

RESUMO

Previous research suggests that it is difficult to maintain cooperation in a large society when there is a strong hierarchical structure. In this study, we implement online human experiments to study the effects of exogenous variation in a particular notion of hierarchy on cooperation and conflict within groups. We demonstrate how cooperation can be maintained when collective action is accompanied by dyadic conflicts whose outcome feeds back on the hierarchical rank of the contestants. We find that the majority of individuals take part in conflicts and that highly ranked individuals mostly cooperate and engage in conflicts as a way to punish noncooperators. As a consequence, stable hierarchical groups can arise and maintain high levels of cooperation. Our results are in agreement with the prediction of earlier theoretical models on hierarchical societies and are relevant to understanding the interplay of hierarchy, cooperation, and conflict.

8.
Cir Esp (Engl Ed) ; 101(3): 208-212, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35792247

RESUMO

Congenital diaphragmatic hernia incidence is one in 3000 live births, Bochdalek hernia occurs through a posterolateral defect. It is very rare in adults. We present a case of late relapsed one diagnosed in an adult male. He underwent an open intervention of Bochdalek hernia at first day of life and required reintervention at seventh month due to recurrence. Now, computerized tomography scan demonstrates a right diaphragmatic defect with intrathoracic hydronephrotic kidney. Nephrectomy was performed with Video-assisted Thoracic Surgery using laparoscopic ports and material. The diaphragmatic defect was closed with a polypropylene mesh. The patient was discharged after 72 h.


Assuntos
Hérnias Diafragmáticas Congênitas , Humanos , Masculino , Adulto , Hérnias Diafragmáticas Congênitas/cirurgia , Nefrectomia , Tomografia Computadorizada por Raios X , Cirurgia Torácica Vídeoassistida , Rim/anormalidades , Rim/cirurgia
9.
J Clin Pathol ; 76(4): 266-273, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34725195

RESUMO

AIMS: Several classification systems are used for pseudomyxoma peritonei. The four-tiered classification system proposed by Peritoneal Surface Oncology Group International (PSOGI) and the two-tiered proposed by the eighth edition of the American Joint Committee on Cancer (AJCC) result from evolution in terminology and pathological insight. The aim is to evaluate the impact of PSOGI and eighth edition of the AJCC classifications on survival. METHODS: Pathological slides were reviewed from a prospectively maintained database including patients treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for an appendiceal mucinous neoplasm with peritoneal dissemination between January 2009 and December 2019. Patients were reclassified according to PSOGI and AJCC eighth edition criteria. Survival analysis evaluated the impact of each classification system on overall survival (OS) and disease-free survival (DFS) while the concordance-index evaluated their predictive power. RESULTS: 95 patients were identified; 21.1% were reclassified as acellular mucin, 55.8% as low-grade mucinous carcinoma peritonei, 8.4% as high-grade MCP (HGMCP) and 14 as HGMCP with signet ring cells. Median OS was not reached, 5-year OS and DFS were 86.1% and 51.5%, respectively. Multivariate analysis revealed significant associations with OS (PSOGI: HR 10.2, p=0.039; AJCC: HR 7.7, p=0.002) and DFS (PSOGI: HR 12.7, p=0.001; AJCC: HR 3.7, p<0.001). The predictive capacity of both classification systems was unacceptable for OS and DFS (concordance-index values <0.7). CONCLUSIONS: Both classification systems behaved similarly when stratifying our series into prognostic groups. The PSOGI classification provides better histopathological description, but histology alone is insufficient for adequate patient prognostication.


Assuntos
Neoplasias do Apêndice , Apêndice , Neoplasias Císticas, Mucinosas e Serosas , Neoplasias Peritoneais , Pseudomixoma Peritoneal , Humanos , Apêndice/patologia , Neoplasias Peritoneais/terapia , Neoplasias Peritoneais/patologia , Neoplasias do Apêndice/terapia , Neoplasias do Apêndice/patologia , Pseudomixoma Peritoneal/terapia , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida
10.
Cir Cir ; 90(S1): 61-69, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35944117

RESUMO

BACKGROUND: Portal vein occlusion shortly before extended hepatic resections has hepatoprotective properties, but its molecular effects have not been elucidated. We characterized the impact of regenerative preconditioning by portal vein embolization (PVE) on hepatic energy metabolism and cytokine expression. MATERIALS AND METHODS: About 90% hepatectomies were performed in normal pigs (Control) and in pigs that underwent a PVE 24 h before the surgery (n = 10/group). Blood biochemistry and coagulation, liver damage, liver function (ICG), hepatic content of adenine nucleotides, and hepatic expression of inflammatory mediators (RT-PCR and WB) were determined before the hepatectomy, 15 min, and 24 h later. RESULTS: All PVE and hepatectomies were successfully accomplished. The 90% hepatectomy resulted in: Immediate reduction of ATP, leading to persistent decreases of energy load and ATP/ADP ratio up to the 24-h time-point; and pro-inflammatory expression profile of cytokines in the remnant liver. Prior performance of PVE attenuated the bioenergetic alterations and prevented many of the changes in hepatic cytokine expression. CONCLUSIONS: Regenerative preconditioning by PVE improved hepatic energy metabolism and modulated inflammatory mediators in the remnant liver in pigs undergoing major hepatectomies, potentially contributing to its hepatoprotective effects.


INTRODUCCIÓN: la oclusión de la vena porta precoz antes de hepatectomías extendidas tiene propiedades hepatoprotectoras, pero sus efectos moleculares no se han aclarado. Caracterizamos el impacto del preacondicionamiento regenerativo por embolización de la vena porta (PVE) sobre el metabolismo energético hepático y la expresión de citocinas. MATERIALES Y MÉTODOS: Realizamos hepatectomías del 90% en cerdos (Control) y en cerdos sometidos a PVE 24 horas antes de la cirugía (n = 10/grupo). La bioquímica y la coagulación, el daño hepático, la función hepática (ICG), los nucleótidos de adenina y la expresión de mediadores inflamatorios (RT-PCR y WB) fueron determinado antes de la hepatectomía, quince minutos y 24 horas después. RESULTADOS: Las PVE y las hepatectomías se realizaron con éxito. La hepatectomía del 90% resultó en: una reducción del ATP, lo que disminuye la carga energética y la relación ATP/ADP a las 24 horas; y en la expresión de citocinas proinflamatorias. La realización previa de PVE atenuó las alteraciones bioenergéticas y evitó muchos de los cambios en la expresión de citocinas. CONCLUSIONES: El preacondicionamiento regenerativo con PVE mejoró el metabolismo energético y moduló los mediadores inflamatorios en el hígado remanente en cerdos sometidos a hepatectomías subtotales, contribuyendo potencialmente a sus efectos hepatoprotectores.


Assuntos
Embolização Terapêutica , Neoplasias Hepáticas , Trifosfato de Adenosina , Animais , Citocinas , Embolização Terapêutica/métodos , Hepatectomia/métodos , Mediadores da Inflamação , Fígado/cirurgia , Neoplasias Hepáticas/cirurgia , Veia Porta/cirurgia , Suínos , Resultado do Tratamento
11.
Materials (Basel) ; 15(4)2022 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-35208101

RESUMO

The procedure generally used to remove bacterial biofilm adhering to the surface of titanium on dental implants is implantoplasty. This treatment is based on the machining of the titanium surface to remove bacterial plaque. In this study, we used 60 grade 4 titanium implants and performed the implantoplasty protocol. Using X-ray diffraction, we determined the stresses accumulated in each of the as-received, machined and debris implants. The resistance to corrosion in open circuit and potentiodynamically in physiological medium has been determined, and the corrosion potentials and intensities have been determined. Tests have been carried out to determine ion release by ICP-MS at different immersion times. The results show that the corrosion resistance and the release of titanium ions into the medium are related to the accumulated energy or the degree of deformation. The titanium debris exhibit compressive residual stresses of -202 MPa, the implant treated with implantoplasty -120 MPa, and as-received -77 MPa, with their corrosion behavior resulting in corrosion rates of 0.501, 0.77, and 0.444 mm/year, respectively. Debris is the material with the worst corrosion resistance and the one that releases the most titanium ions to the physiological medium (15.3 ppb after 21 days vs. 7 ppb for as-received samples). Pitting has been observed on the surface of the debris released into the physiological environment. This behavior should be taken into account by clinicians for the good long-term behavior of implants with implantoplasty.

12.
PLoS One ; 16(12): e0260163, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34890389

RESUMO

Conferences are ideal platforms for studying gender gaps in science because they are important cultural events that reflect barriers to women in academia. Here, we explored women's participation in ecology conferences by analyzing female representation, behavior, and personal experience at the 1st Meeting of the Iberian Society of Ecology (SIBECOL). The conference had 722 attendees, 576 contributions, and 27 scientific sessions. The gender of attendees and presenters was balanced (48/52% women/men), yet only 29% of the contributions had a woman as last author. Moreover, men presented most of the keynote talks (67%) and convened most of the sessions. Our results also showed that only 32% of the questions were asked by women, yet the number of questions raised by women increased when the speaker or the convener was a woman. Finally, the post-conference survey revealed that attendees had a good experience and did not perceive the event as a threatening context for women. Yet, differences in the responses between genders suggest that women tended to have a worse experience than their male counterparts. Although our results showed clear gender biases, most of the participants of the conference failed to detect it. Overall, we highlight the challenge of increasing women's scientific leadership, visibility and interaction in scientific conferences and we suggest several recommendations for creating inclusive meetings, thereby promoting equal opportunities for all participants.


Assuntos
Ecologia/métodos , Comportamento , Feminino , Humanos , Liderança , Masculino , Percepção , Sexismo
13.
Sci Rep ; 10(1): 15359, 2020 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-32958841

RESUMO

Many animal and human societies exhibit hierarchical structures with different degrees of steepness. Some of these societies also show cooperative behavior, where cooperation means working together for a common benefit. However, there is an increasing evidence that rigidly enforced hierarchies lead to a decrease of cooperation in both human and non-human primates. In this work, we address this issue by means of an evolutionary agent-based model that incorporates fights as social interactions governing a dynamic ranking, communal work to produce a public good, and norm internalization, i.e. a process where acting according to a norm becomes a goal in itself. Our model also includes the perception of how much the individual is going to retain from her cooperative behavior in future interactions. The predictions of the model resemble the principal characteristics of human societies. When ranking is unconstrained, we observe a high concentration of agents in low scores, while a few ones climb up the social hierarchy and exploit the rest, with no norm internalization. If ranking is constrained, thus leading to bounded score differences between agents, individual positions in the ranking change more, and the typical structure shows a division of the society in upper and lower classes. In this case, we observe that there is a significant degree of norm internalization, supporting large fractions of the population cooperating in spite of the rank differences. Our main results are robust with respect to the model parameters and to the type of rank constraint. We thus provide a mechanism that can explain how hierarchy arises in initially egalitarian societies while keeping a large degree of cooperation.


Assuntos
Comportamento Cooperativo , Hierarquia Social , Normas Sociais , Evolução Biológica , Mecanismos de Defesa , Humanos , Sociedades
14.
J Gastrointest Surg ; 24(6): 1386-1391, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32314232

RESUMO

BACKGROUND: The "Small-for-Size" syndrome is defined as a liver failure after a liver transplant with a reduced graft or after a major hepatectomy. The later coined "Small-for-Flow" syndrome describes the same situation in liver resections but based on hemodynamic intraoperative parameters (portal pressure > 20 mmHg and/or portal flow > 250 ml/min/100 g). This focuses on the damage caused by the portal hyperafflux related to the volume of the remnant. METHODS: Relevant studies were reviewed using Medline, PubMed, and Springer databases. RESULTS: Portal hypertension after partial hepatectomies also leads to a higher morbidity and mortality. There are plenty of experimental studies focusing on flow rather than size. Some of them also perform different techniques to modulate the portal inflow. The deleterious effect of high posthepatectomy portal venous pressure is known, and that is why the idea of portal flow modulation during major hepatectomies in humans is increasing in everyday clinical practice. CONCLUSIONS: Considering the extensive knowledge obtained with the experimental models and good results in clinical studies that analyze the "Small-for-Flow" syndrome, we believe that measuring portal flow and portal pressure during major liver resections should be performed routinely in extended liver resections. Applying these techniques, the knowledge of hepatic hemodynamics would be improved in order to advance against posthepatectomy liver failure.


Assuntos
Circulação Hepática , Falência Hepática , Hemodinâmica , Hepatectomia/efeitos adversos , Humanos , Fígado/cirurgia , Regeneração Hepática , Pressão na Veia Porta , Veia Porta/cirurgia
15.
J Gastrointest Surg ; 23(11): 2174-2183, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-30734180

RESUMO

INTRODUCTION: The term "Small-for-Flow" reflects the pathogenetic relevance of hepatic hemodynamics for the "Small-For-Size" syndrome and posthepatectomy liver failure. We aimed to characterize a large-animal model for studying the "Small-for-Flow" syndrome. METHODS: We performed subtotal (90%) hepatectomies in 10 female MiniPigs using a simplified transection technique with a tourniquet. Blood tests, hepatic and systemic hemodynamics, and hepatic function and histology were assessed before (Bas), 15 min (t-15 min) and 24 h (t-24 h) after the operation. Some pigs underwent computed tomography (CT) scans for hepatic volumetry (n = 4) and intracranial pressure (ICP) monitoring (n = 3). Postoperative care was performed in an intensive care unit environment. RESULTS: All hepatectomies were successfully performed, and hepatic volumetry confirmed liver remnant volumes of 9.2% [6.2-11.2]. The hepatectomy resulted in characteristic hepatic hemodynamic alterations, including portal hyperperfusion, relative decrease of hepatic arterial blood flow, and increased portal pressure (PP) and portal-systemic pressure gradient. The model reproduced major diagnostic features including the development of cholestasis, coagulopathy, encephalopathy with increased ICP, ascites, and renal failure, hyperdynamic circulation, and hyperlactatemia. Two animals (20%) died before t-24 h. Histological liver damage was observed at t-15 min and at t-24 h. The degree of histological damage at t-24 h correlated with intraoperative PP (r = 0.689, p = 0.028), hepatic arterial blood flow (r = 0.655, p = 0.040), and hepatic arterial pulsatility index (r = 0.724, p = 0.066). All animals with intraoperative PP > 20 mmHg presented liver damage at t-24 h. CONCLUSION: The present 90% hepatectomy porcine experimental model is a feasible and reproducible model for investigating the "Small-for-Flow" syndrome.


Assuntos
Hepatectomia/efeitos adversos , Artéria Hepática/fisiopatologia , Circulação Hepática/fisiologia , Falência Hepática/cirurgia , Regeneração Hepática/fisiologia , Fígado/cirurgia , Pressão na Veia Porta/fisiologia , Animais , Modelos Animais de Doenças , Feminino , Fígado/irrigação sanguínea , Falência Hepática/fisiopatologia , Suínos , Porco Miniatura , Síndrome
16.
Rev. cuba. cir ; 57(3): e682, jul.-set. 2018. tab
Artigo em Espanhol | LILACS | ID: biblio-985518

RESUMO

Introducción: El síndrome adherencial es la causa más frecuente de obstrucción de intestino delgado. La laparotomía es el abordaje estándar. El avance de la cirugía mínimamente invasiva hace posible la resolución de cuadros obstructivos por laparoscopia. Objetivo: Analizar el abordaje laparoscópico de la obstrucción intestinal y compararlo con la vía abierta. Método: Análisis retrospectivo de los pacientes tratados de obstrucción intestinal aguda mediante laparoscopia en nuestro hospital desde 2012 hasta 2016. Se utilizó como referencia un grupo de pacientes tratados desde 2002 hasta 2005, cuando sólo se usaba el abordaje abierto. Se analizaron datos demográficos, riesgo quirúrgico, comorbilidades, métodos diagnósticos y complicaciones (Clavien). Resultados: De los 134 pacientes intervenidos de obstrucción intestinal aguda, se inició un abordaje laparoscópico en 47 (35 pr ciento). Por esta vía sólo se completaron 32 pacientes (68 por ciento). La tasa de conversión fue del 32 por ciento, estos pacientes fueron eliminados del estudio. En el grupo de referencia se analizaron al azar 32 pacientes. Ambos grupos son comparables. El grupo tratado con abordaje laparoscópico tuvo un 9 por ciento de complicaciones y un 3 por ciento de reintervenciones, con una sola lesión inadvertida. El grupo laparoscópico tuvo un 12,5 por ciento de reintervenciones, todas por evisceración, pero tuvo una lógica mayor tasa de resecciones intestinales. No hubo mortalidad hospitalaria. Conclusión: Los resultados en los pacientes en que se ha completado la cirugía por laparoscopia se comparan favorablemente con los del abordaje abierto en un grupo histórico homogéneo de referencia, y sin el riesgo añadido de evisceración(AU)


Introduction: Adherence syndrome is the most frequent cause of small bowel obstruction. Laparotomy is the standard approach. The progress of minimally invasive surgery makes it possible to resolve obstructive frames by laparoscopy. Objective: To analyze the laparoscopic approach for intestinal obstruction and compare it with the open pathway. Method: Retrospective analysis of patients treated for acute intestinal obstruction by laparoscopy in our hospital, from 2012 to 2016. A group of patients treated from 2002 to 2005 were used as reference, when only the open approach was used. We analyzed demographic data, surgical risk, comorbidities, diagnostic methods and complications (Clavien). Results: Within the 134 patients operated for acute intestinal obstruction, a laparoscopic approach was started in 47 (35 percent). Only 32 patients (68 percent) were completed in this way. The conversion rate was 32 percent, these patients were eliminated from the study. In the reference group, 32 patients were randomly analyzed. Both groups are comparable. The group treated with laparoscopic approach had 9 por ciento complications and 3 percent reoperations, with a single unexpected lesion. The laparoscopic group had 12.5 of reintervention, all due to evisceration, but had a higher rate of intestinal resections. There was no hospital mortality. Conclusion: In patients who have completed laparoscopic surgery, the results are compared favorably with those of the open approach in a homogeneous historical reference group, and without the added risk of evisceration(AU)


Assuntos
Humanos , Inquéritos de Morbidade , Laparoscopia/métodos , Conversão para Cirurgia Aberta/estatística & dados numéricos , Obstrução Intestinal/cirurgia , Estudos Retrospectivos , Procedimentos Cirúrgicos Minimamente Invasivos/métodos
17.
Sci Rep ; 8(1): 9093, 2018 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-29904185

RESUMO

Reputation plays a key role among the mechanisms supporting cooperation in our society. This is a well-known observation and, in fact, several studies have shown that reputation may substantially increase cooperation among subjects playing Prisoner's Dilemma games in the laboratory. Unfortunately, recent experiments indicate that when reputation can be faked cooperation can still be maintained at the expense of honest subjects who are deceived by the dishonest ones. As experimental work is limited due to financial and other reasons, we present here an agent-based simulation model inspired by, and calibrated against, the results obtained in the experiment. We thus simulate much larger population sizes over longer times, and test other model parameters to see whether the observed behavior generalizes in those yet untried conditions. The results show that the collective behavior is qualitatively similar in larger systems and stable over longer times horizons. We conclude that the findings of the experimental work are meaningful, taking into account that the model is strictly tailored to our particular experimental setting and therefore it is a possible explanation of our observations whose applicability to other contexts requires further research. We argue that simulations like the ones presented here may also be useful to cheaply and quickly suggest settings and options to enhance and facilitate further experiments, which, in turn, may provide new tests of the models themselves.

18.
J Sci Food Agric ; 98(12): 4625-4633, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29516500

RESUMO

BACKGROUND: Glass frits with a P2 O5 /K2 O ratio equal to 0.65 and different concentrations of SiO2 (6.5-56.0 wt%), CaO (0-5.1 wt%) and Al2 O3 (0-14.6 wt%) have been prepared and analysed as potential glass fertilizers (GF). RESULTS: P2 O5 and K2 O were leached primarily within the first 5 days but the total amount was dependent on the SiO2 /Al2 O3 ratio of the glass frit. Sustained P2 O5 and K2 O leaching for more than 40 days could be obtained if the glass frit contained more than 7% Al2 O3 . A final glass frit composition (29% SiO2 , 5% CaO, 7% Al2 O3 , 30% P2 O5 , 25% K2 O) was selected and used in an experimental tomato crop of 1 ha area, where one half was fertilized with an NPK conventional fertilizer and the other half with the GF fertilizer. CONCLUSION: After harvesting the tomato crops, the GF fertilizer was found to result in a higher yield than the NPK conventional fertilizer: 59980 kg and 74 360 kg for NKP and GF, respectively. The general characteristics of the harvested tomato fruits and leaves were similar in the two cases and the differences fell within statistical error. No differences in any of the soil characteristics were detected as a result of the use of GF. © 2018 Society of Chemical Industry.


Assuntos
Fertilizantes/análise , Solanum lycopersicum/crescimento & desenvolvimento , Agricultura , Produtos Agrícolas/química , Produtos Agrícolas/crescimento & desenvolvimento , Frutas/química , Frutas/crescimento & desenvolvimento , Solanum lycopersicum/química , Dióxido de Silício/análise , Solo/química
20.
Inorg Chem ; 56(7): 4148-4156, 2017 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-28318233

RESUMO

The mechanism by which Zr-substituted and other transition metal-substituted polyoxometalates (POMs) form covalently linked dimers has been analyzed by means of static density functional theory (DFT) calculations with a continuous solvent model as well as Car-Parrinello molecular dynamics (CPMD) simulations with explicit solvent molecules. The study includes different stages of the process: the formation of the active species by alkalination of the solution and formation of intercluster linkages. CPMD simulations show that the Zr-triaqua precursor, [W5O18Zr(H2O)3]2-, under basic conditions, reacts with hydroxide anions to form Zr-aqua-hydroxo active species, [W5O18Zr(OH)(H2O)]3-. We computed the DFT potential energy profile for dimerization of [W5O18TM(OH)]n- [TM = ZrIV(H2O), ZrIV, TiIV, and WVI] anions. The resulting overall energy barrier is low for ZrIV, moderate for TiIV, and high for WVI. The computed thermodynamic balance favors the dibridged (µOH)2 linkages for ZrIV, the monobridged (µOH) linkage for TiIV, and the monomeric forms for WVI, in agreement with experimentally observed trends. The lowest energy barrier and largest coordination number of Zr-substituted POMs are both a consequence of the flexible coordination environment and larger radius of Zr.

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