2,709 research outputs found
Fortress with Sticky Moats: the Functional Role of Small Particles around Tetragonisca angustula Latreille (Apidae: Hymenoptera) Nest Entrance
Many bee species are able to defend themselves against pollen or honey thievery. We herein report the functional role of small sticky particles deposited by Tetragonisca angustula Latreille in its nest entrance external side. This strategy was very effective to prevent ants from invading the beesâ nest. We reported many dead ants attached to the nest entrance and different ant species easily immobilized after being moved onto the entrance tube containing sticky particles. This is the first description of the functional role played by the nest entrance sticky particles under natural conditions.
Systematic study of luminescent properties of new lanthanide complexes using crown ethers as ligand
AbstractThis is a report on the synthesis, characterization and spectroscopic study of 24 lanthanide-crown ether coordination compounds, where Eu(III), Tb(III) and Gd(III) were complexes to 12-crown-4 (12C4), 15-crown-5 (15C5), 1,10-phenanthroline (phen) and 2,2âČ-dipyridyl (dipy). The compounds were synthesized in an ethanol/acetone solution at room temperature and analyzed using CHN elemental analysis and infrared, absorption and emission spectroscopies. The polarizability that the ligand exerts on the emission process was verified and found remarkable. The Eu-15C5-phen complex showed the highest quantum efficiency (71.6%) because of its low non-radiative rate and highest polarizability with reference to the ligands system
Cassava starch coatings for postharvest control of papaya anthracnose
The effects of coating papaya fruit (Carica papaya) with cassava starch were studied, to determine the best concentration and mode of action of this material in postharvest control of anthracnose. The concentrations of starch tested were 1%, 2%, 3% and 4%. These were prepared to give gel consistency. Surface sterilized papaya fruits were inoculated with conidia of Colletotrichum gloeosporioides and incubated for 48 h in a moisture chamber. The were then treated with cassava fruit gels and dried. During the following 14 d storage period, fruit maturation and anthracnose on the fruits were assessed, and electron microscopy was used to examine fruit epicarps. All cassava starch coating concentrations reduced fruit maturation and anthracnose, with the 2%, 3% or 4% coatings giving 100% disease control. The 2% starch coating is likely to be optimum, considering the lower cost efficiency of disease control. The mechanism of disease control provided by the coating is likely to be related to delay of ripening and the formation of a protective layer over the fruit
Hallucinations in Large Multilingual Translation Models
Large-scale multilingual machine translation systems have demonstrated
remarkable ability to translate directly between numerous languages, making
them increasingly appealing for real-world applications. However, when deployed
in the wild, these models may generate hallucinated translations which have the
potential to severely undermine user trust and raise safety concerns. Existing
research on hallucinations has primarily focused on small bilingual models
trained on high-resource languages, leaving a gap in our understanding of
hallucinations in massively multilingual models across diverse translation
scenarios. In this work, we fill this gap by conducting a comprehensive
analysis on both the M2M family of conventional neural machine translation
models and ChatGPT, a general-purpose large language model~(LLM) that can be
prompted for translation. Our investigation covers a broad spectrum of
conditions, spanning over 100 translation directions across various resource
levels and going beyond English-centric language pairs. We provide key insights
regarding the prevalence, properties, and mitigation of hallucinations, paving
the way towards more responsible and reliable machine translation systems
Radiative Transfer in Prestellar Cores: A Monte Carlo Approach
We use our Monte Carlo radiative transfer code to study non-embedded
prestellar cores and cores that are embedded at the centre of a molecular
cloud. Our study indicates that the temperature inside embedded cores is lower
than in isolated non-embedded cores, and generally less than 12 K, even when
the cores are surrounded by an ambient cloud of small visual extinction (Av~5).
Our study shows that the best wavelength region to observe embedded cores is
between 400 and 500 microns, where the core is quite distinct from the
background. We also predict that very sensitive observations (~1-3 MJy/sr) at
170-200 microns can be used to estimate how deeply a core is embedded in its
parent molecular cloud. Finally, we present preliminary results of asymmetric
models of non-embedded cores.Comment: 8 pages, 15 figures, to appear in the conference proceedings of "Open
Issues in Local Star Formation and Early Stellar Evolution", held in Ouro
Preto (Brazil), April 5-10, 200
Heptamethine Cyanine-Loaded Nanomaterials for Cancer Immuno-Photothermal/Photodynamic Therapy: A Review
The development of strategies capable of eliminating metastasized cancer cells and preventing tumor recurrence is an exciting and extremely important area of research. In this regard, therapeutic approaches that explore the synergies between nanomaterial-mediated phototherapies and immunostimulants/immune checkpoint inhibitors have been yielding remarkable results in pre-clinical cancer models. These nanomaterials can accumulate in tumors and trigger, after irradiation of the primary tumor with near infrared light, a localized temperature increase and/or reactive oxygen species. These effects caused damage in cancer cells at the primary site and can also (i) relieve tumor hypoxia, (ii) release tumor-associated antigens and danger-associated molecular patterns, and (iii) induced a pro-inflammatory response. Such events will then synergize with the activity of immunostimulants and immune checkpoint inhibitors, paving the way for strong T cell responses against metastasized cancer cells and the creation of immune memory. Among the different nanomaterials aimed for cancer immuno-phototherapy, those incorporating near infrared-absorbing heptamethine cyanines (Indocyanine Green, IR775, IR780, IR797, IR820) have been showing promising results due to their multifunctionality, safety, and straightforward formulation. In this review, combined approaches based on phototherapies mediated by heptamethine cyanine-loaded nanomaterials and immunostimulants/immune checkpoint inhibitor actions are analyzed, focusing on their ability to modulate the action of the different immune system cells, eliminate metastasized cancer cells, and prevent tumor recurrence.info:eu-repo/semantics/publishedVersio
A multi-scale, multi-wavelength source extraction method: getsources
We present a multi-scale, multi-wavelength source extraction algorithm called
getsources. Although it has been designed primarily for use in the far-infrared
surveys of Galactic star-forming regions with Herschel, the method can be
applied to many other astronomical images. Instead of the traditional approach
of extracting sources in the observed images, the new method analyzes fine
spatial decompositions of original images across a wide range of scales and
across all wavebands. It cleans those single-scale images of noise and
background, and constructs wavelength-independent single-scale detection images
that preserve information in both spatial and wavelength dimensions. Sources
are detected in the combined detection images by following the evolution of
their segmentation masks across all spatial scales. Measurements of the source
properties are done in the original background-subtracted images at each
wavelength; the background is estimated by interpolation under the source
footprints and overlapping sources are deblended in an iterative procedure. In
addition to the main catalog of sources, various catalogs and images are
produced that aid scientific exploitation of the extraction results. We
illustrate the performance of getsources on Herschel images by extracting
sources in sub-fields of the Aquila and Rosette star-forming regions. The
source extraction code and validation images with a reference extraction
catalog are freely available.Comment: 31 pages, 27 figures, to be published in Astronomy & Astrophysic
Helping WWTP managers to address the volatile methylsiloxanes issue-Behaviour and complete mass balance in a conventional plant
Volatile methylsiloxanes (VMSs) are a group of additives employed in different consumer products that can affect the quality of the biogas produced in wastewater treatment plants (WWTPs). The main objective of this study is to understand the fate of different VMSs along the treatment process of a WWTP located in Aveiro (Portugal). Thus, wastewater, sludge, biogas, and air were sampled in different units for two weeks. Subsequently, these samples were extracted and analyzed by different environment-friendly protocols to obtain their VMS (L3-L5, D3-D6) concentrations and profiles. Finally, considering the different matrix flows at every sampling moment, the mass distribution of VMSs within the plant was estimated. The levels of âVMSs were similar to those showed in the literature (0.1-50 Όg/L in entry wastewater and 1-100 Όg/g dw in primary sludge). However, the entry wastewater profile showed higher variability in D3 concentrations (from non detected to 49 Όg/L) than found in previous studies (0.10-1.00 Όg/L), likely caused by isolated releases of this compound that could be related to industrial sources. Outdoor air samples showed a prevalence of D5, while indoor air locations were characterized by a predominance of D3 and D4. Differences in sources and the presence of an indoor air filtration system may explain this divergence. Biogas was characterized by âVMSs concentrations (8.00 ± 0.22 mg/m3) above the limits recommended by some engine manufacturers and mainly composed of D5 (89%). Overall, 81% of the total incoming mass of VMSs is reduced along the WWTP, being the primary decanter and the secondary treatment responsible for the highest decrease (30.6% and 29.4% of the initial mass, respectively). This reduction, however, is congener dependant. The present study demonstrates the importance of extending sampling periods and matrices (i.e., sludge and air) to improve sample representativity, time-sensitivity, and the accuracy of mass balance exercises.This work was financially supported by: (i) Projects LA/P/0045/2020 (ALiCE â Associated Laboratory in Chemical Engineering) and UIDB/00511/2020 and UIDP/00511/2020 (LEPABE â Laboratory for Process Engineering, Environment, Biotechnology and Energy), funded by national funds through FCT/MCTES (PIDDAC); (ii) Project LANSILOT (PTDC/CTA-AMB/32084/2017; POCI-01â0145-FEDER-032084), funded by FEDER through COMPETE2020âPrograma Operacional Competitividade e Internacionalizaçao(POCI) and by national funds (PIDDAC) through FCT/MCTES; (iii) Project âHealthyWaters â Identification, Elimination, Social Awareness and Education of Water Chemical and Biological Micropollutants with Health and Environmental Implicationsâ (NORTE-01-0145-FEDER-000069), co-financed by Programa Operacional Regional do Norte (NORTE 2020), through Portugal 2020 and FEDER; (iv) N. Ratola thanks FCT for the financial support of his work contract through the Scientific Employment Stimulus -Institutional Call - [CEECINST/00049/2018]; (v) G. Pantuzza thanks FCT PhD programme for Grant 2020.07815.BD, supported under the Portugal 2020 Partnership Agreement and European Social Fund (ESF); (vi) V. Homem thanks national funds through FCT, under the Scientific Employment StimulusâIndividual Call - CEECIND/00676/2017. The authors wish to thank the help of the staff at the WWTP in the design of the sampling strategy and the collection of the samples.S
Injecção de Falhas por Varrimento Periférico em Processadores
As tĂ©cnicas de injecção de falhas mais utilizadas podem ser classificadas em tĂ©cnicas de indução, tĂ©cnicas de injecĂŁo por hardware e tĂ©cnicas de injecção por software. Dentro das tĂ©cnicas de injecção por hardware surgem as tĂ©cnicas de injecção de falhas recorrendo Ă tecnologia de teste por varrimento perifĂ©rico. Esta encontra-se fortemente implantada nos processadores mais recentes, fornecendo um mĂ©todo de acesso ao seu interior de forma a permitir operaçÔes de teste e depuração. A sua utilização para a injecção de falhas Ă© um passo lĂłgico e tem sido estudada desde os anos 90. Os trabalhos desenvolvidos nesta ĂĄrea sĂŁo diversos e incluem soluçÔes que nĂŁo exigem qualquer alteração Ă infraestrutura normalizada e soluçÔes que modificam as cĂ©lulas e a infraestrutura de controlo de forma a suportarem esta funcionalidade. Estas alteraçÔes implicam atrasos temporais acrescidos e um aumento da ĂĄrea de silĂcio destinada a funçÔes de teste, tornando-se importante uma preocupação com a optimização para que a inclusĂŁo de capacidades de injecção de falhas nĂŁo afecte significativamente o desempenho e o custo dos componentes onde sĂŁo implementadas.info:eu-repo/semantics/publishedVersio
The Pipe Nebula as seen with Herschel: Formation of filamentary structures by large-scale compression ?
A growing body of evidence indicates that the formation of filaments in
interstellar clouds is a key component of the star formation process. In this
paper, we present new Herschel PACS and SPIRE observations of the B59 and Stem
regions in the Pipe Nebula complex, revealing a rich, organized network of
filaments. The asymmetric column density profiles observed for several
filaments, along with the bow-like edge of B59, indicates that the Pipe Nebula
is being compressed from its western side, most likely by the winds from the
nearby Sco OB2 association. We suggest that this compressive flow has
contributed to the formation of some of the observed filamentary structures. In
B59, the only region of the entire Pipe complex showing star formation
activity, the same compressive flow has likely enhanced the initial column
density of the clump, allowing it to become globally gravitationally unstable.
Although more speculative, we propose that gravity has also been responsible
for shaping the converging filamentary pattern observed in B59. While the
question of the relative impact of large-scale compression and gravity remains
open in B59, large-scale compression appears to be a plausible mechanism for
the initial formation of filamentary structures in the rest of the complexComment: 9 pages, 9 figures, accepted for publication in A&
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