1,680 research outputs found
Water Soluble Cationic Porphyrin Sensor for Detection of Hg2+, Pb2+, Cd2+, and Cu2+
Here we report the sensing properties of the aqueous solution of mesotetra(N-methyl-4-pyridyl)porphine tetrachloride (1) for simultaneous detection of toxic metal ions by using UV-vis spectroscopy. Cationic porphyrin 1 displayed different electronic absorptions in UV-vis region upon interacting with Hg2+, Pb2+, Cd2+, and Cu2+ ions in neutral water solution at room temperature. Quite interestingly, the porphyrin 1 showed that it can function as a single optical chemical sensor and/ or metal ion receptor capable of detecting two or more toxic metal ions, particularly, Hg2+, Pb2+, and Cd2+ ions coexisting in a water sample. Porphyrin 1 in an aqueous solution provides a unique UV-vis sensing system for the determination of Cd2+ in the presence of larger metal ions such as Hg2+, or Pb2+. Finally, the examination of the sensing properties of 1 demonstrated that it can operate as a Cu2+ ion selective sensor via metal displacement from the 1-Hg2+ , 1-Pb2+ , and 1-Cd2+
A Simple Non-equilibrium Feedback Model for Galaxy-Scale Star Formation: Delayed Feedback and SFR Scatter
We explore a class of simple non-equilibrium star formation models within the
framework of a feedback-regulated model of the ISM, applicable to
kiloparsec-scale resolved star formation relations (e.g. Kennicutt-Schmidt).
Combining a Toomre-Q-dependent local star formation efficiency per free-fall
time with a model for delayed feedback, we are able to match the normalization
and scatter of resolved star formation scaling relations. In particular, this
simple model suggests that large (dex) variations in star formation rates
(SFRs) on kiloparsec scales may be due to the fact that supernova feedback is
not instantaneous following star formation. The scatter in SFRs at constant gas
surface density in a galaxy then depends on the properties of feedback and when
we observe its star-forming regions at various points throughout their
collapse/star formation "cycles". This has the following important
observational consequences: (1) the scatter and normalization of the
Kennicutt-Schmidt relation are relatively insensitive to the local
(small-scale) star formation efficiency, (2) but gas depletion times and
velocity dispersions are; (3) the scatter in and normalization of the
Kennicutt-Schmidt relation is a sensitive probe of the feedback timescale and
strength; (4) even in a model where deterministically
dictates star formation locally, time evolution, variation in local conditions
(e.g., gas fractions and dynamical times), and variations between galaxies can
destroy much of the observable correlation between SFR and
in resolved galaxy surveys. Additionally, this model exhibits large scatter in
SFRs at low gas surface densities, in agreement with observations of flat outer
HI disk velocity dispersion profiles.Comment: 15 pages, 6 figures, accepted by MNRAS (04/25/2019
Lattices with skew-Hermitian forms over division algebras and unlikely intersections
This paper has two objectives. First, we study lattices with skew-Hermitian
forms over division algebras with positive involutions. For division algebras
of Albert types I and II, we show that such a lattice contains an "orthogonal"
basis for a sublattice of effectively bounded index. Second, we apply this
result to obtain new results in the field of unlikely intersections. More
specifically, we prove the Zilber-Pink conjecture for the intersection of
curves with special subvarieties of simple PEL type I and II under a large
Galois orbits conjecture. We also prove this Galois orbits conjecture for
certain cases of type II.Comment: 60 page
The large Galois orbits conjecture under multiplicative degeneration
We establish the PEL type large Galois orbits conjecture for Hodge generic
curves in possessing multiplicative degeneration. Combined with
our earlier works, this concludes the proof of the Zilber-Pink conjecture in
for such curves. We also deduce several new cases of
Zilber-Pink in for . Our proof uses Andr\'e's
G-functions method, using formal and rigid uniformisation of semiabelian
schemes to interpret the -adic evaluations of the period G-functions.Comment: 66 page
The epidemiology of injuries in Australian professional Rugby Union 2014 Super Rugby competition
BACKGROUND: Rugby union is a collision-based ball sport played at the professional level internationally. Rugby union has one of the highest reported incidences of injury of all team sports. PURPOSE: To identify the characteristics, incidence, and severity of injuries occurring in Australian professional Super Rugby Union. DESIGN: Descriptive epidemiology study. METHODS: The present study was a prospective epidemiology study on a cohort of 180 professional players from 5 Australian Super Rugby teams during the 2014 Super Rugby Union Tournament. Team medical staff collected and submitted daily training and match-play injury data through a secure, web-based electronic platform. The injury data included the main anatomic location of the injury, specific anatomic structure of the injury, injury diagnosis, training or match injury occurrence, main player position, mechanism of injury, and the severity of the injury quantified based on the number of days lost from training and/or competition due to injury. RESULTS: The total combined incidence rate for injury during training and match-play across all Australian Super Rugby Union teams was 6.96 per 1000 hours, with a mean injury severity of 37.45 days lost from training and competition. The match-play injury incidence rate was 66.07 per 1000 hours, with a mean severity of 39.80 days lost from training and competition. No significant differences were observed between forward- and back-playing positions for match or training injury incidence rate or severity. CONCLUSION: The incidence of injury for the present study was lower during match-play than has previously been reported in professional rugby union; however, the overall time loss was higher compared with previous studies in professional rugby union. The high overall time loss was due fundamentally to a high incidence of injuries with greater than 28 days’ severity
Differences in heart rates between general officers and instructors employing defensive tactics skills
Can Foundation Models Wrangle Your Data?
Foundation Models (FMs) are models trained on large corpora of data that, at
very large scale, can generalize to new tasks without any task-specific
finetuning. As these models continue to grow in size, innovations continue to
push the boundaries of what these models can do on language and image tasks.
This paper aims to understand an underexplored area of FMs: classical data
tasks like cleaning and integration. As a proof-of-concept, we cast five data
cleaning and integration tasks as prompting tasks and evaluate the performance
of FMs on these tasks. We find that large FMs generalize and achieve SoTA
performance on data cleaning and integration tasks, even though they are not
trained for these data tasks. We identify specific research challenges and
opportunities that these models present, including challenges with private and
domain specific data, and opportunities to make data management systems more
accessible to non-experts. We make our code and experiments publicly available
at: https://github.com/HazyResearch/fm_data_tasks.Comment: 12 pages, 5 figures; additional experiments, typo corrections,
modifications to Section 5 (Research Agenda
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