Abstract
AT 2020mot is a typical UV/optical tidal disruption event (TDE) with no radio or X-ray signatures in a quiescent host. We find an
i
-band excess and rebrightening along the decline of the ...light curve which could be due to two consecutive dust echoes from the TDE. We model our observations following van Velzen et al. and find that the near-infrared light curve can be explained by concentric rings of thin dust within ∼0.1 pc of a ∼6 × 10
6
M
⊙
supermassive black hole (SMBH), among the smallest scales at which dust has been inferred near SMBHs. We find dust covering factors of order
f
c
≤ 2%, much lower than found for dusty tori of active galactic nuclei. These results highlight the potential of TDEs for uncovering the environments around black holes when including near-infrared observations in high-cadence transient studies.
Abstract AT 2019azh is a H+He tidal disruption event (TDE) with one of the most extensive ultraviolet and optical data sets available to date. We present our photometric and spectroscopic ...observations of this event starting several weeks before and out to approximately 2 yr after the g -band's peak brightness and combine them with public photometric data. This extensive data set robustly reveals a change in the light-curve slope and a possible bump in the rising light curve of a TDE for the first time, which may indicate more than one dominant emission mechanism contributing to the pre-peak light curve. Indeed, we find that the MOSFiT -derived parameters of AT 2019azh, which assume reprocessed accretion as the sole source of emission, are not entirely self-consistent. We further confirm the relation seen in previous TDEs whereby the redder emission peaks later than the bluer emission. The post-peak bolometric light curve of AT 2019azh is better described by an exponential decline than by the canonical t −5/3 (and in fact any) power-law decline. We find a possible mid-infrared excess around the peak optical luminosity, but cannot determine its origin. In addition, we provide the earliest measurements of the H α emission-line evolution and find no significant time delay between the peak of the V -band light curve and that of the H α luminosity. These results can be used to constrain future models of TDE line formation and emission mechanisms in general. More pre-peak 1–2 days cadence observations of TDEs are required to determine whether the characteristics observed here are common among TDEs. More importantly, detailed emission models are needed to fully exploit such observations for understanding the emission physics of TDEs.
Presence of Sergentomyia in Tunisia Chemkhi, Jomaa; Guerbouj, Souheila; Saadawi, Walid ...
Journal of medical entomology,
03/2019, Letnik:
56, Številka:
2
Journal Article
Recenzirano
In Tunisia, 17 phlebotomine sand fly species are reported, belonging to genera Phlebotomus and Sergentomyia. However, subsequentto faunal studies and outbreaks of leishmaniasis in different regions ...of the country, unrecognized sand fly species could exist. Indeed, we report in this study the presence of Sergentomyia (Parrotomyia) lewisi Parrot 1948. A brief collection of phlebotomine sand flies was undertaken in August 2016 in Khbina locality, in Sidi Bouzid governorate situated in CentralTunisia, which constitutes an old focus of Zoonotic Cutaneous Leishmaniasis. Sand flies were collected, using CDC light traps that were placed overnight, in different biotopes (inside habitations, outdoors, and within animal shelters). Specimens were collected and morphologically identified. Measurements were taken with an ocular micrometer. Two female specimens of the species Se. (Parrotomyia) lewisi were collected. One specimen is here described and measured. A comparison of its taxonomic characters to the holotype from Sudan and a specimen from Algeria is also presented. This species was until now only reported from Sudan, Ethiopia, Algeria, and Morocco. It is here described for the first time inTunisia, which raises theTunisian sand fly fauna to seven subgenera and 18 species. Key words: phlebotomine sand fly, Sergentomyia (Parrotomyia) lewisi, Tunisia
In Tunisia, 17 phlebotomine sand fly species are reported, belonging to genera Phlebotomus and Sergentomyia. However, subsequent to faunal studies and outbreaks of leishmaniasis in different regions ...of the country, unrecognized sand fly species could exist. Indeed, we report in this study the presence of Sergentomyia (Parrotomyia) lewisi Parrot 1948. A brief collection of phlebotomine sand flies was undertaken in August 2016 in Khbina locality, in Sidi Bouzid governorate situated in CentralTunisia, which constitutes an old focus of Zoonotic Cutaneous Leishmaniasis. Sand flies were collected, using CDC light traps that were placed overnight, in different biotopes (inside habitations, outdoors, and within animal shelters). Specimens were collected and morphologically identified. Measurements were taken with an ocular micrometer.Two female specimens of the species Se. (Parrotomyia) lewisi were collected. One specimen is here described and measured. A comparison of its taxonomic characters to the holotype from Sudan and a specimen from Algeria is also presented. This species was until now only reported from Sudan, Ethiopia, Algeria, and Morocco. It is here described for the first time inTunisia, which raises theTunisian sand fly fauna to seven subgenera and 18 species.
Extreme coronal line emitters (ECLEs) are objects showing transient high-ionization lines in the centers of galaxies. They have been attributed to echoes of high-energy flares of ionizing radiation, ...such as those produced by tidal disruption events (TDEs), but have only recently been observed within hundreds of days after an optical transient was detected. AT 2022upj is a nuclear UV-optical flare at z=0.054 with spectra showing Fe X {\lambda}6375 and Fe XIV {\lambda}5303 during the optical peak, the earliest presence of extreme coronal lines during an ongoing transient. AT 2022upj is also the second ever ECLE (and first with a concurrent flare) to show broad He II {\lambda}4686 emission, a key signature of optical/UV TDEs. We also detect X-ray emission during the optical transient phase, which may be related to the source of ionizing photons for the extreme coronal lines. Finally, we analyze the spectroscopic evolution of each emission line and find that Fe X and Fe XIV weaken within 400d of optical peak, while Fe VII {\lambda}5720, Fe VII {\lambda}6087, and O III {\lambda}{\lambda}4959,5007 emerge over the same period. The velocities of the iron lines indicate circumnuclear gas within 0.1pc of the central supermassive black hole (SMBH), while a dust echo inferred from NEOWISE data indicates that circumnuclear dust lies at a minimum of 0.4pc away, providing evidence of stratified material around a SMBH. AT 2022upj is the first confirmed ECLE-TDE with clear signatures of both classes. This event's spectroscopic evolution on a \(\sim\)year unveils the impact of highly energetic flares such as TDEs on the complex environments around SMBHs.
AT 2020mot is a typical UV/optical tidal disruption event (TDE) with no radio or X-ray signatures in a quiescent host. We find an i-band excess and re-brightening along the decline of the light curve ...which could be due to two consecutive dust echoes from a TDE. We model our observations following van Velzen et al. (2016) and find that the near-infrared light curve can be explained by concentric rings of thin dust within \(\sim\)0.1 parsecs of a 6e6 M\(_{\odot}\) supermassive black hole (SMBH), among the smallest scales at which dust has been inferred near SMBHs. We find dust covering factors of order fc \(\leq\) 2%, much lower than found for dusty tori of active galactic nuclei. These results highlight the potential of TDEs for uncovering the environments around black holes when including near-infrared observations in high-cadence transient studies.
AT 2019azh is a H+He tidal disruption event (TDE) with one of the most extensive ultraviolet and optical datasets available to date. We present our photometric and spectroscopic observations of this ...event starting several weeks before and out to approximately two years after g-band peak brightness and combine them with public photometric data. This extensive dataset robustly reveals a change in the light-curve slope and a bump in the rising light curve of a TDE for the first time, which may indicate more than one dominant emission mechanism contributing to the pre-peak light curve. We further confirm the relation seen in previous TDEs whereby the redder emission peaks later than the bluer emission. The post-peak bolometric light curve of AT 2019azh is better described by an exponential decline than by the canonical t^{-5/3} (and in fact any) power-law decline. We find a possible mid-infrared excess around peak optical luminosity, but cannot determine its origin. In addition, we provide the earliest measurements of the Halpha emission-line evolution and find no significant time delay between the peak of the V-band light curve and that of the Halpha luminosity. These results can be used to constrain future models of TDE line formation and emission mechanisms in general. More pre-peak 1-2 day cadence observations of TDEs are required to determine whether the characteristics observed here are common among TDEs. More importantly, detailed emission models are needed to fully exploit such observations for understanding the emission physics of TDEs.
Aim
Intake of caffeinated energy drinks has significantly increased, specifically among young adults and adolescents. College students are prone to developing unhealthy eating habits and dependence ...on stimulants, which puts them at a greater risk of sleep problems. This study aims to investigate the prevalence of caffeinated energy drink consumption and its association with sleep quality in college students.
Methods
A sample of 919 randomly selected adults (237 males and 682 females) from various colleges at the University of Sharjah/United Arab Emirates participated in this cross‐sectional study. Data were collected using an online validated questionnaire.
Results
The current study revealed that 376 students (41%) were consuming energy drinks on a regular basis. Approximately half of the students had normal sleep patterns; the other half had sleep problems (anxiety and intermittent sleep). Results of the present study revealed a significant (r = −0.10, P < 0.05) relationship between the consumption of energy drinks and sleep quality and patterns.
Conclusions
Moderate consumption of energy drinks was reported among college students. Consumption of energy drinks was significantly associated with changes in sleep quality and patterns of students.
Lung cancer screening saves lives, but implementation is challenging. We evaluated two approaches to early lung cancer detection-low-dose computed tomography screening (LDCT) and program-based ...management of incidentally detected lung nodules.
A prospective observational study enrolled patients in the early detection programs. For context, we compared them with patients managed in a Multidisciplinary Care Program. We compared clinical stage distribution, surgical resection rates, 3- and 5-year survival rates, and eligibility for LDCT screening of patients diagnosed with lung cancer.
From 2015 to May 2021, 22,886 patients were enrolled: 5,659 in LDCT, 15,461 in Lung Nodule, and 1,766 in Multidisciplinary Care. Of 150, 698, and 1,010 patients diagnosed with lung cancer in the respective programs, 61%, 60%, and 44% were diagnosed at clinical stage I or II, whereas 19%, 20%, and 29% were stage IV (
= .0005); 47%, 42%, and 32% had curative-intent surgery (
< .0001); aggregate 3-year overall survival rates were 80% (95% CI, 73 to 88) versus 64% (60 to 68) versus 49% (46 to 53); 5-year overall survival rates were 76% (67 to 87) versus 60% (56 to 65) versus 44% (40 to 48), respectively. Only 46% of 1,858 patients with lung cancer would have been deemed eligible for LDCT by US Preventive Services Task Force (USPSTF) 2013 criteria, and 54% by 2021 criteria. Even if all eligible patients by USPSTF 2021 criteria had been enrolled into LDCT, the Nodule Program would have detected 20% of the stage I-II lung cancer in the entire cohort.
LDCT and Lung Nodule Programs are complementary, expanding access to early lung cancer detection and curative treatment to different-risk populations. Implementing Lung Nodule Programs may alleviate emerging disparities in access to early lung cancer detection.
Purpose
Gamma-secretase inhibitor MK0752 has shown a high therapeutic potential in different solid malignant tumors. Up to now, its antineoplastic effects were not investigated in head and neck ...squamous cell carcinoma (HNSCC) and particularly in human-papillomavirus (HPV)-positive tumors.
Methods
We conducted cytotoxic, migration, and clonogenic assays in two HPV-negative HNSCC cell lines (Cal27 and FaDu) and one HPV-positive cell line (SCC154). Furthermore, in order to assess the pro-apoptotic effects of MK0752, a Caspase 3/7 Glo assay was performed.
Results
Our experiments revealed antineoplastic effects of MK0752 in all three cell lines. Strong cytotoxic and antimigratory potential was shown in all cell lines, with strongest effects observed in the HPV-positive cell line. Meanwhile, anticlonogenic effects were only shown in Cal27 and SCC154. Most importantly, MK0752 induced apoptosis solely in HPV-positive SCC154.
Conclusions
Our novel findings indicate a therapeutic potential of MK0752 in HPV-positive HNSCC. Indeed, further investigation is needed for validation of our results and for the assessment of the mechanistic background.
