New Gd4-6-10 and Gd5-7-12 Cuprate Superconductors Supelano, G. I.; Buitrago, D. Martinez; Gómez, J. A. Mejía ...
Journal of low temperature physics,
11/2020, Letnik:
201, Številka:
3-4
Journal Article
Recenzirano
This paper describes the Gd
x
−2
Ba
x
Cu
2
x
−2
O
δ
(
x
= 6, 7) cuprate system synthesis using the conventional solid-state reaction method. Rietveld analysis of X-ray patterns evidences that ...samples crystallize in
Pmm
2 (#25) space group at room temperature with lattice parameter
a
= 3.8807 Å,
b
= 3.8735 Å,
c
= 38.7094 Å for Gd
4
Ba
6
Cu
10
O
δ
and
a
= 3.8680 Å,
b
= 3.8763 Å,
c
= 46.5065 for Gd
5
Ba
7
Cu
12
O
δ
. Resistivity measurements evidence zero-resistance state, which is a typical behavior of superconducting materials at bulk critical temperature of 15.5 K for Gd
4
Ba
6
Cu
10
O
δ
and 22.1 K for Gd
5
Ba
7
Cu
12
O
δ
.
There are a few reports regarding the treatment of traumatic vertebral arteriovenous fistulas and pseudoaneurysms. Our aim was to describe the clinical and angiographic results of endovascular ...therapy for traumatic injuries of the vertebral artery.
The clinical and angiographic features of 18 traumatic injuries of the vertebral artery during an 8-year period were reviewed. There were 14 male (78%) and 4 female patients (22%). The average age was 28 years (range, 11-49 years). Of the 18 lesions of the vertebral artery, 17 (95%) were the result of penetrating trauma (gunshot or stab wound injury) and 1 (5%) was iatrogenic (jugular vein catheter). In 16 (89%) instances, the injury resulted in an arteriovenous fistula, and in the other 2 (11%), in a pseudoaneurysm. All patients were treated with an endovascular approach by using different techniques (balloon occlusion, coil embolization, and/or stent deployment).
Endovascular therapy resulted in immediate lesion total occlusion in 16 (89%) patients. Delayed total occlusion was demonstrated angiographically during follow-up in the 2 remaining patients. Clinical improvement was documented in all patients, and there were no clinically symptomatic complications.
In this small series, endovascular techniques were a safe and effective method of treatment and were not associated with significant morbidity or mortality.
In this article we outline the role evidence and argument plays in the construction of a framing theory for Proof Based Teaching of basic operations on natural numbers and integers, which uses tiles ...to physically represent numbers. We adopt Mariotti’s characterization of a mathematical theorem as a triple of statement, proof and theory, and elaborate a theory in which the statement “The product of two negative integers is a positive integer” can be proved. This theory is described in terms of a ‘toolbox’ of accepted statements, and acceptable forms of argumentation and expression. We discuss what counts as mathematical evidence in this theory and how that evidence is used in mathematical arguments that support the theory.
Understanding the factors driving the diet breadth of phytophagous insects remains one of the main questions in ecological research. In this study we explored the diet breadth and plant-insect ...associations in the plume moth
Lioptilodes friasi
Vargas & Parra (Lepidoptera: Pterophoridae). This phytophagous insect was originally described in association with a single host species,
Haplopappus foliosus
(Asteraceae), a native shrub of the Chilean Mediterranean matorral. In order to address the breadth of host plant choice, we surveyed other
Haplopappus
species growing along the elevation gradient of central Chile from sea level to 2600 m. We were able to obtain
L. friasi
adults from five additional
Haplopappus
species:
Haplopappus chrysantemifolius
and
Haplopappus decurrens
from the coastal zone,
Haplopappus multifolius
and
Haplopappus schumanii
from the mid-elevation zone, and
Haplopappus scrobiculatus
at high elevation. Our results demonstrate that the genus-specialized endophagous herbivore
L. friasi
has a wider distribution and climatic tolerance than previously described. Its biogeographical range extends from the lowland coastal habitats up to the Andean subnival level. We propose that shared flower phenotypic traits such as morphology and chemical composition may have allowed the colonization of closely related
Haplopappus
species in central Chile, the expansion of which is limited by the harsh high elevation conditions.
Soldiers in active military service need optimal physical fitness for successfully carrying out their operations. Therefore, their health status is regularly checked by army doctors. These ...inspections include physical parameters such as the body-mass index (BMI), functional tests, and biochemical studies. If a medical exam reveals an individual's excess weight, further examinations are made, and corrective actions for weight lowering are initiated. The collection of urine is non-invasive and therefore attractive for frequent metabolic screening. We compared the chemical profiles of urinary samples of 146 normal weight, excess weight, and obese soldiers of the Mexican Army, using untargeted metabolomics with liquid chromatography coupled to high-resolution mass spectrometry (LC-MS). In combination with data mining, statistical and metabolic pathway analyses suggest increased S-adenosyl-L-methionine (SAM) levels and changes of amino acid metabolites as important variables for overfeeding. We will use these potential biomarkers for the ongoing metabolic monitoring of soldiers in active service. In addition, after validation of our results, we will develop biochemical screening tests that are also suitable for civil applications.
Variation in the language experience of bilinguals has consequences for cognitive and affective processes. In the current study, we examined how bilingual experience influences the relationship ...between language and emotion in English among a group of Spanish–English heritage bilinguals on an emotion–memory task. Participants rated the emotionality of English taboo, negative and neutral words and then completed an unexpected recognition test. To account for language experience, data were gathered on the participants’ language dominance and proficiency. Results showed emotion–memory effects in the Spanish–English heritage bilinguals’ English (the societal language): taboo words were recognized significantly better than neutral words, while the emotionality of negative words carried over and significantly affected the recognition of preceding neutral words. Furthermore, such effects were modulated by language dominance scores with more pronounced emotion–memory effects in more English-dominant bilinguals. The findings contribute to a growing body of evidence showing that emotions are not necessarily restricted to the first acquired home language. Critically, for heritage speakers, there is often a shift in language dominance from the home language to the societal language. The present study demonstrates that the effects of emotion on memory are seen in the acquired societal language.
The progressive rise of mature CD5 super(+) B lymphocytes, despite the low proportion of proliferating cells, has led to the notion that B cell chronic lymphocytic leukemia (B-CLL) is primarily ...related to defective apoptosis. The microenvironment likely plays a prominent role because the malignant cells progressively accumulate in vivo, whereas they rapidly undergo spontaneous apoptosis when cultured in vitro. To assess microenvironment-mediated survival signals, B-CLL cells were cultured with a murine fibroblast cell line, Ltk super(-), with and without an agonistic antibody to CD40. Spontaneous apoptosis was associated with the loss of Akt and NF- Kappa B activities. Interactions with fibroblasts sustained a basal level of Akt and NF- Kappa B activities, which was dependent on phosphatidylinositol-3 kinase (PI3K). Constitutive activity of the PI3K pathway in B-CLL cells when cultured with fibroblasts prevented the down-regulation of the prosurvival Bcl-2 family protein Bcl-x sub(L) and the caspase inhibitor proteins FLIP sub(L) and XIAP, and consequently caspase-3 activation and apoptosis. CD40 crosslinking in B-CLL cells did not further prevent murine fibroblasts-mediated apoptosis but induced cell proliferation, which was associated with an increase of Akt and NF- Kappa B activation compared with cells cultured with fibroblasts alone. The PI3K pathway seems to play a pivotal role in B-CLL cell survival and growth.
This paper presents a survey on multi-robot search inspired by swarm intelligence by further classifying and discussing the theoretical advantages and disadvantages of the existing studies. ...Subsequently, the most attractive techniques are evaluated and compared by highlighting their most relevant features. This is motivated by the gradual growth of swarm robotics solutions in situations where conventional search cannot find a satisfactory solution. For instance, exhaustive multi-robot search techniques, such as sweeping the environment, allow for a better avoidance of local solutions but require too much time to find the optimal one. Moreover, such techniques tend to fail in finding targets within dynamic and unstructured environments. This paper presents experiments conducted to benchmark five state-of-the-art algorithms for cooperative exploration tasks. The simulated experimental results show the superiority of the previously presented Robotic Darwinian Particle Swarm Optimization (RDPSO), evidencing that sociobiological inspiration is useful to meet the challenges of robotic applications that can be described as optimization problems (e.g., search and rescue). Moreover, the RDPSO is further compared with the best performing algorithms within a population of 14 e-pucks. It is observed that the RDPSO algorithm converges to the optimal solution faster and more accurately than the other approaches without significantly increasing the computational demand, memory and communication complexity.
•A survey on multi-robot search inspired on swarm intelligence is presented.•Five state-of-the-art swarm robotic algorithms are described and compared.•Simulated experiments of a mapping task are carried out to compare the five algorithms.•The three best performing algorithms are deeply compared using 14 e-pucks on a source localization problem.•The Robotic Darwinian Particle Swarm Optimization (RDPSO) algorithm depicts an improved convergence.
•We analyze the dissolved oxygen content and its spatial distribution in 90 Chilean Fjords.•We identify their oxic (>2mLL−1) and hypoxic (<2mLL−1) conditions.•We propose physical and biogeochemical ...processes to explain the oxic and hypoxic observed conditions.•We infer that the physical processes are more relevant than biogeochemical processes in their ventilation.•We conclude that out of the 90 studied channels and fjords, 86 are oxic, 4 are permanently hypoxic and none are anoxic.
Chilean Patagonia is one of the largest estuarine systems in the world. It is characterized by a complex geography of approximately 3300 islands, a total surface area of 240,000km2, and 84,000km of coast line, including islands, peninsulas, channels, fjords, and sounds. The Chilean Patagonia Interior Sea is filled with a mixture of sea, estuarine, and fresh waters, and is characterized by a two layer vertical general circulation. Dissolved oxygen (DO) conditions in these fjords were analyzed based on historic salinity, dissolved oxygen and nutrient data from 1200 oceanographic stations. Horizontal advection of adjacent well oxygenated Subantarctic Waters (5–6mLL−1) was the mayor source of DO in the deep layers of the Interior Sea. Incoming DO was consumed by the respiration of autochthonous and allochthonous particulate organic matter, as ocean water flows towards the continental fjord heads, reaching near-hypoxic (2–3mLL−1) or hypoxic levels (<2mLL−1). As DO declined nutrient concentrations increased towards the fjord heads (from ∼1.6μM PO4−3 and ∼16μM NO3− to ∼2.4μM PO4−3 and ∼24μM NO3−). Overall, DO conditions in the Interior Sea were mostly the result of a combination of physical and biogeochemical processes. In all eastern channels and fjords, a low DO zone developed near the fjord heads (<4mLL−1) as a result of larger allochthonous particulate organic matter inputs transported by local rivers. This enhanced organic matter input to the deep layer increased DO consumption due to respiration and overwhelmed the oxygen supplied by horizontal advection. Out of the 90 Chilean Patagonian gulfs, channels and fjords analyzed, 86 systems were oxic (>2mLL−1) and four hypoxic (<2mLL−1), but only at their heads. None were found to be anoxic (0mLL−1). We found these DO conditions to be permanent features of the Chilean Patagonia Interior Sea.
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