850 research outputs found
Resilience and adaptability of rice terrace social-ecological systems: A case study of a local communityâs perception in Banaue, Philippines
© 2016 by the author(s). The social-ecological systems of rice terraces across Southeast Asia are the result of centuries of long-term interactions between human communities and their surrounding ecosystems. Processes and structures in these systems have evolved to provide a diversity of ecosystem services and benefits to human societies. However, as Southeast Asian countries experience rapid economic growth and related land-use changes, the remaining extensive rice cultivation systems are increasingly under pressure. We investigated the long-term development of ecosystem services and the adaptive capacity of the social-ecological system of rice terrace landscapes using a case study of Banaue (Ifugao Province, Northern-Luzon, Philippines). A set of indicators was used to describe and assess changes in the social-ecological state of the study system. The resilience of the rice terraces and the human communities that maintain them was examined by comparing the current state of the system with results from the literature. Our findings indicate that, although the social-ecological system has not yet shifted to an alternative state, pressures are increasing and some cultural ecosystem services have already been lost
Analysis of By-Products of N2-SF6 Gas Mixtures Sparked under Inhomogenous Field Conditions
A vast data on formation of by-products due to arc and spark decomposition of SF6 is available in literature [1â10]. But experimental work relating to N2 - SF6 gas mixtures is limited. In view of increasing application of gas mixtures, it is essential to understand the nature of by-products formed in gas mixtures. Many recent studies have highlighted the advantages of using N2-SF6 gas mixtures as a replacement to SF6 gas for High Voltage application, with a view to reduce emission of SF6 gas into the atmosphere. Majority of these studies are aimed at determining the basic characteristics of N2-SF6 gas mixtures. However, this study attempts to understand the nature and quantum of different species formed in N2-SF6 mixtures in the presence of insulating spacers when sparked under inhomogeneous field conditions
Shark predation on migrating adult american eels (Anguilla rostrata) in the Gulf of St. Lawrence.
In an attempt to document the migratory pathways and the environmental conditions encountered by American eels during their oceanic migration to the Sargasso Sea, we tagged eight silver eels with miniature satellite pop-up tags during their migration from the St. Lawrence River in Québec, Canada. Surprisingly, of the seven tags that successfully transmitted archived data, six were ingested by warm-gutted predators, as observed by a sudden increase in water temperature. Gut temperatures were in the range of 20 to 25°C-too cold for marine mammals but within the range of endothermic fish. In order to identify the eel predators, we compared their vertical migratory behavior with those of satellite-tagged porbeagle shark and bluefin tuna, the only endothermic fishes occurring non-marginally in the Gulf of St. Lawrence. We accurately distinguished between tuna and shark by using the behavioral criteria generated by comparing the diving behavior of these two species with those of our unknown predators. Depth profile characteristics of most eel predators more closely resembled those of sharks than those of tuna. During the first days following tagging, all eels remained in surface waters and did not exhibit diel vertical migrations. Three eels were eaten at this time. Two eels exhibited inverse diel vertical migrations (at surface during the day) during several days prior to predation. Four eels were eaten during daytime, whereas the two night-predation events occurred at full moon. Although tagging itself may contribute to increasing the eel's susceptibility to predation, we discuss evidence suggesting that predation of silver-stage American eels by porbeagle sharks may represent a significant source of mortality inside the Gulf of St. Lawrence and raises the possibility that eels may represent a reliable, predictable food resource for porbeagle sharks
Effects of Geochemical and Environmental Parameters on Abiotic Organic Chemistry Driven by Iron Hydroxide Minerals
Geological conditions play a significant role in prebiotic/abiotic organic chemistry, especially when reactive minerals are present. Previous studies of the prebiotic synthesis of amino acids and other products in mineralâcontaining systems have shown that a diverse array of compounds can be produced, depending on the experimental conditions. However, these previous experiments have not simulated the effects of varying geochemical conditions, in which factors such as pH, iron redox state, or chemical concentrations may vary over time and space in a natural environment. In geochemical systems that contain overlapping gradients, many permutations of individual conditions could exist and affect the outcome of an organic reaction network. We investigated reactions of pyruvate and glyoxylate, two compounds that are central to the emergence of metabolism, in simulated geological gradients of redox, pH, and ammonia concentration. Our results show that the positioning of pyruvate/glyoxylate reactions in this environmental parameter space determines the organic product distribution that results. Therefore, the distribution pattern of amino acids and alphaâhydroxy acids produced prebiotically in a system reflects the specific reaction conditions, and would be distinct at various locations in an environment depending on local geochemistry. This is significant for origin of life chemistry in which the composition and function of oligomers could be affected by the environmentally driven distribution of monomers available. Also, for astrobiology and planetary science where organic distribution patterns are sometimes considered as a possible biosignature, it is important to consider environmentally driven abiotic organic reactions that might produce similar effects
Mott Transition, Compressibility Divergence and P-T Phase Diagram of Layered Organic Superconductors: An Ultrasonic Investigation
The phase diagram of the organic superconductor
-(BEDT-TTF)Cu[N(CN)Cl has been investigated by ultrasonic
velocity measurements under helium gas pressure. Different phase transitions
were identified trough several elastic anomalies characterized from isobaric
and isothermal sweeps. Our data reveal two crossover lines that end on the
critical point terminating the first-order Mott transition line. When the
critical point is approached along these lines, we observe a dramatic softening
of the velocity which is consistent with a diverging compressibility of the
electronic degrees of freedom.Comment: 4 pages, 5 figure
Evidence of Late Ediacaran Hyperextension of the Laurentian Iapetan Margin in the Birchy Complex, Baie Verte Peninsula, Northwest Newfoundland: Implications for the Opening of Iapetus, Formation of PeriLaurentian Microcontinents and Taconic â Grampian Orogenesis
The Birchy Complex of the Baie Verte Peninsula, northwestern Newfoundland, comprises an assemblage of mafic schist, ultramafic rocks, and metasedimentary rocks that are structurally sandwiched between overlying ca. 490 Ma ophiolite massifs of the Baie Verte oceanic tract and underlying metasedimentary rocks of the Fleur de Lys Supergroup of the Appalachian Humber margin. Birchy Complex gabbro yielded a Late Ediacaran UâPb zircon IDâTIMS age of 558.3 ± 0.7 Ma, whereas gabbro and an intermediate tuffaceous schist yielded LAâICPMS concordia zircon ages of 564 ± 7.5 Ma and 556 ± 4 Ma, respectively. These ages overlap the last phase of rift-related magmatism observed along the Humber margin of the northern Appalachians (565â550 Ma). The associated ultramafic rocks were exhumed by the Late Ediacaran and shed detritus into the interleaved sedimentary rocks. Psammite in the overlying Flat Point Formation yielded a detrital zircon population typical of the Laurentian Humber margin in the northern Appalachians. Age relationships and characteristics of the Birchy Complex and adjacent Rattling Brook Group suggest that the ultramafic rocks represent slices of continental lithospheric mantle exhumed onto the seafloor shortly before or coeval with magmatic accretion of mid-ocean ridge basalt-like mafic rocks. Hence, they represent the remnants of an ocean â continent transition zone formed during hyperextension of the Humber margin prior to establishment of a mid-ocean ridge farther outboard in the Iapetus Ocean. We propose that microcontinents such as Dashwoods and the Rattling Brook Group formed as a hanging wall block and an extensional crustal allochthon, respectively, analogous to the isolation of the Briançonnais block during the opening of the Alpine LigurianâPiemonte and Valais oceanic seaways.Le complexe de Birchy de la pĂ©ninsule de Baie Verte, dans le nord-ouest de Terre-Neuve, est constituĂ© dâun assemblage de schistes mafiques, de roches ultramafiques et de mĂ©tasĂ©diments qui sont coincĂ©s entre des massifs ophiolitiques dâascendance ocĂ©anique de la Baie Verte au-dessus, et des mĂ©tasĂ©diments du Supergroupe de Fleur de Lys de la marge de Humber des Appalaches en-dessous. Le complexe de gabbro de Birchy a donnĂ© une datation U-Pb sur zircon ID-TIMS correspondant Ă la fin de lâĂdiacarien, soit 558,3 ± 0,7 Ma, alors quâun gabbro et un schiste tufacĂ© intermĂ©diaire montrent une datation LA-ICP-MS Concordia sur zircon de 564 ± 7,5 Ma et 556 ± 4 Ma, respectivement. Ces datations chevauchent la derniĂšre phase de magmatisme de rift observĂ©e le long de la marge Humber des Appalaches du Nord (565-550 Ma). Les roches ultramafiques associĂ©es ont Ă©tĂ© exhumĂ©es vers la fin de lâĂdiacarien et leurs dĂ©bris ont Ă©tĂ© imbriquĂ©s dans des roches sĂ©dimentaires. Les psammites de la Formation de Flat Point susjacente ont donnĂ© une population de zircons dĂ©tritiques typique de la marge laurentienne de Humber des Appalaches du Nord. Les relations chronologiques et les caractĂ©ristiques du complexe de Birchy et du groupe de Rattling Brook adjacent, permettent de penser que ces roches ultramafiques pourraient ĂȘtre des Ă©cailles de manteau lithosphĂ©rique continental qui auraient Ă©tĂ© exhumĂ©es sur le plancher ocĂ©anique peu avant ou en mĂȘme temps que lâaccrĂ©tion magmatique de roches mafiques basaltiques de type dorsale mĂ©dio-ocĂ©anique. Par consĂ©quent, elles seraient des vestiges dâune zone de transition ocĂ©an-continent formĂ©e au cours de lâhyper-extension de la marge de Humber avant lâapparition dâune dorsale mĂ©dio-ocĂ©anique plus loin au large dans lâocĂ©an IapĂ©tus. Nous proposons que des microcontinents comme de Dashwoods et du groupe de Rattling Brook ont constituĂ©s respectivement un bloc de toit et un allochtone crustal dâextension, de la mĂȘme maniĂšre que le bloc Briançonnais a Ă©tĂ© isolĂ© lors de lâouverture des bras ocĂ©aniques alpins de Ligurie-PiĂ©mont et de Valais.Fil: Van Staal, Cees R.. Geological Survey of Canada; CanadĂĄFil: Chew, Dave M.. Trinity College Dublin; IrlandaFil: Zagorevski, Alexandre. Geological Survey of Canada; CanadĂĄFil: Mcnicoll, Vicki. Geological Survey of Canada; CanadĂĄFil: Hibbard, James. North Carolina State University; Estados UnidosFil: Skulski, Tom. Geological Survey of Canada; CanadĂĄFil: Castonguay, SĂ©bastien. Geological Survey of Canada; CanadĂĄFil: Escayola, Monica Patricia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de Estudios Andinos; ArgentinaFil: Sylvester, Paul J.. Memorial University Of Newfoundland; Canad
Provider Perspectives on Rapid Treatment Initiation Among People Newly Diagnosed With HIV: A New Message of âUrgencyâ?
Background
Early initiation of antiretroviral therapy improves human immunodeficiency virus (HIV) outcomes. However, achieving earlier treatment initiation is challenging for many reasons including provider awareness and clinic barriers; this study sought to understand perceptions of an early initiation program.
Methods
We interviewed 10 providers from 3 HIV clinics in North Carolina (October-November 2020). We asked providers about overall perceptions of early initiation and the pilot program. We developed narrative summaries to understand individual contexts and conducted thematic analysis using NVivo.
Results
Providers believed earlier initiation would signal an âextra sense of urgencyâ about the importance of antiretroviral therapyâa message not currently reflected in standard of care. Safety was a consistent concern. Cited implementation barriers included transportation assistance, medication sustainability, and guidance to address increased staff time and appointment availability.
Conclusion
Our qualitative findings highlight the need for training on the safety of early initiation and addressing staffing needs to accommodate quicker appointments.Plain Language Summary
Doctor and clinic staff perspectives on a program to immediately start HIV treatment among patients newly diagnosed with HIV
Treating human immunodeficiency virus (HIV) is easier than ever. Starting newly diagnosed persons on HIV medication as soon as possible is a now recommended goal. However, starting patients right away can be challenging. This study interviewed doctors and clinic staff to better understand their perspectives prior to implementing a program that would provide newly diagnosed patients with HIV treatment immediately. Results showed that some doctors are worried patients will not return after receiving their medications. Providers want support for linking patients to the clinic and ensuring they will be able to receive their next dose of medication when they come in. Other providers saw the benefits of reducing HIV stigma if the program can more quickly start patients on treatment. Some providers explained that when you go to the doctor and are sick you receive medications immediately, yet for newly diagnosed patients living with HIV, patients can be told to come back a month later to start treatment. Some providers believe shifting this messaging may also help patients take their medications better. Most providers saw the need for clinics to have more same-day appointment availability to meet the needs of the new program. Overall, providers were excited about the opportunity to improve the HIV care by offering HIV medications to newly diagnosed patients immediately
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