4,713 research outputs found
Constraining weak annihilation using semileptonic D decays
The recently measured semileptonic D_s decay rate can be used to constrain
weak annihilation (WA) effects in semileptonic D and B decays. We revisit the
theoretical predictions for inclusive semileptonic D_{(s)} decays using a
variety of quark mass schemes. The most reliable results are obtained if the
fits to B decay distributions are used to eliminate the charm quark mass
dependence, without using any specific charm mass scheme. Our fit to the
available data shows that WA is smaller than commonly assumed. There is no
indication that the WA octet contribution (which is better constrained than the
singlet contribution) dominates. The results constrain an important source of
uncertainty in the extraction of |Vub| from inclusive semileptonic B decays.Comment: 5 pages, 2 figures, published versio
Theoretical investigation of the scope of sequential ligand tuning using a bifunctional scorpionate tris(1,2,4-triazolyl)borate-based architecture
The donor properties of a series of tripodal mixed N-donor/carbene ligands derived through sequential alkylation of hydrotris(1,2,4-triazolyl)borate have been investigated by density functional theory (DFT) methods. The structures of complexes of the form [Mo(L)(CO)3]- were optimized (L = [HB(1,2,4-triazolyl)n(1,2,4-triazol-5-ylidene)3-n]- (n = 0 – 3), hydrotris(pyrazolyl)borate, hydrotris(3,5-dimethylpyrazolyl)borate and hydrotris(imidazol-2-ylidene)borate) and nuCO frequencies for these complexes and partial charges of their Mo(CO)3 fragments were determined. Results show that ligand donation is highly tunable when compared to similar experimentally known ligands with a shift in the symmetric nuCO stretching mode of -39 cm -1 on going from the tris(1,2,4-triazolyl)borate complexes to that of the triscarbene hydrotris(1,2,4-triazol-5-ylidene) and an increase in partial charge (distributed multipole analysis) of the Mo(CO)3 fragment from -0.23 to -0.48
Implicit Large-Eddy Simulations of Hot and Cold Supersonic Jets in Loci-CHEM
This paper introduces a 4th-order accurate low-dissipation flux scheme for use on un- structured CFD codes, and compares this flux scheme with two others for LES calculations of hot and cold supersonic jets. The flux schemes are compared with experimental profiles of jet centerline Mach number, total temperature and total pressure, with jet spreading rate data, and with near- field acoustic measurements. The influence of grid resolution on these solution accuracy is also evaluated. The new low-dissipation flux scheme is shown to be stable on a high-speed compressible turbulent ow problem, and to be significantly more accurate than the existing baseline flux approach
Temporal tracking of mineralization and transcriptional developments of shell formation during the early life history of pearl oyster Pinctada maxima
Molluscan larval ontogeny is a highly conserved process comprising three principal developmental stages. A characteristic unique to each of these stages is shell design, termed prodissoconch I, prodissoconch II and dissoconch. These shells vary in morphology, mineralogy and microstructure. The discrete temporal transitions in shell biomineralization between these larval stages are utilized in this study to investigate transcriptional involvement in several distinct biomineralization events. Scanning electron microscopy and X-ray diffraction analysis of P. maxima larvae and juveniles collected throughout post-embryonic ontogenesis, document the mineralogy and microstructure of each shelled stage as well as establishing a timeline for transitions in biomineralization. P. maxima larval samples most representative of these biomineralization distinctions and transitions were analyzed for differential gene expression on the microarray platform PmaxArray 1.0. A number of transcripts are reported as differentially expressed in correlation to the mineralization events of P. maxima larval ontogeny. Some of those isolated are known shell matrix genes while others are novel; these are discussed in relation to potential shell formation roles. This interdisciplinary investigation has linked the shell developments of P. maxima larval ontogeny with corresponding gene expression profiles, furthering the elucidation of shell biomineralization
Tiny House Permitting in San Luis Obispo
Tiny houses are a rising trend in housing that provide affordable, environmentally friendly dwellings for those inclined to a minimalist lifestyle. Across the Unites States, municipalities have begun creating special provisions for tiny houses, but there remain many barriers to building and permitting tiny houses affordably. There has been much progress in the acceptance of ADUs (Accessory Dwelling Units), specifically in the state of California. Legislation on ADUs leads the way for the community integration of tiny houses. This study investigates the current state of legislation and permitting for tiny houses in San Luis Obispo, California. An interview was conducted with a local authority on tiny house legislation, and three mini case studies were conducted on model practices in other municipalities. Information from the interview and the case studies was synthesized into a recommendation for the City of San Luis Obispo on how to alter their current legislation model
To Be a Whistleblower, or Not to Be a Whistleblower? That Is the Question-Whether \u27Tis Nobler in the Mind of the Courts to Suffer for Reporting Wrongdoing to the SEC or Employers Internally: Examining the Recent Circuit Split Regarding the Definition of a Whistleblower Under Dodd-Frank
Under the current state of the law, the circuit courts are split over whether an employee must report corporate wrongdoing directly to the Securities and Exchange Commission (SEC), or report wrongdoing to a company’s management in order to receive whistleblower protection under Dodd–Frank. The resolution of this circuit split not only will have implications for American employees caught in situations similar to the fiction above, but also will provide a prime opportunity for the Supreme Court to clarify how courts are to understand the interpretive and deferential relationship between the language of legislative statutes and their corresponding bureaucratic regulations. In Berman v. Neo@Ogilvy LLC, the Second Circuit ruled that a “whistleblower” is not required to report corporate “wrongdoing” to the SEC to be covered under the “anti-retaliation protection” provided by the Dodd–Frank Act. The Second Circuit’s ruling in Berman created a circuit split with the Fifth Circuit’s decision in Asadi v. G.E. Energy U.S., L.L.C., which held that a “whistleblower” was required to report misconduct to the SEC to receive Dodd–Frank protections. The main difference between these two decisions is how each circuit deciphered different definitions of a whistleblower based on differing statutory interpretations of the relationship between the Dodd–Frank Act and the corresponding SEC regulations. The goal of this Comment is to conduct a thorough analysis of this recent circuit split and examine the implications regarding its pending reconciliation
Hadronic Spectral Moments in Semileptonic B Decays With a Lepton Energy Cut
We compute the first two moments of the final hadronic invariant mass in
inclusive semileptonic B decay, in the presence of a cut on the charged lepton
energy. These moments may be measured directly by experiments at the
Upsilon(4S) using the neutrino reconstruction technique, which requires such a
cut. Measurement of these moments will place constraints on the nonperturbative
parameters \bar\Lambda and \lambda_1, which are relevant for extracting the
quark masses m_b and m_c, as well as the CKM angle V_cb. We include terms of
order \alpha_s^2\beta_0 and 1/m_b^3 in the operator product expansion, and use
the latter to estimate the theoretical uncertainty in the extraction of
\bar\Lambda and \lambda_1.Comment: 13 pages, 5 figures, REVTe
Logistic Knowledge Tracing: A Constrained Framework for Learner Modeling
Adaptive learning technology solutions often use a learner model to trace
learning and make pedagogical decisions. The present research introduces a
formalized methodology for specifying learner models, Logistic Knowledge
Tracing (LKT), that consolidates many extant learner modeling methods. The
strength of LKT is the specification of a symbolic notation system for
alternative logistic regression models that is powerful enough to specify many
extant models in the literature and many new models. To demonstrate the
generality of LKT, we fit 12 models, some variants of well-known models and
some newly devised, to 6 learning technology datasets. The results indicated
that no single learner model was best in all cases, further justifying a broad
approach that considers multiple learner model features and the learning
context. The models presented here avoid student-level fixed parameters to
increase generalizability. We also introduce features to stand in for these
intercepts. We argue that to be maximally applicable, a learner model needs to
adapt to student differences, rather than needing to be pre-parameterized with
the level of each student's ability
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