6,146 research outputs found
Publisher Correction: Statistical modeling of RNA structure profiling experiments enables parsimonious reconstruction of structure landscapes.
The originally published version of this Article contained an error in Figure 2, due to a typesetting error. Panels d and e were positioned such that the locations of the mutations in panel d did not align correctly with the corresponding nucleotides in the reactivity profile in panel e. This has now been corrected in both the PDF and HTML versions of the Article
Statistical modeling of RNA structure profiling experiments enables parsimonious reconstruction of structure landscapes.
RNA plays key regulatory roles in diverse cellular processes, where its functionality often derives from folding into and converting between structures. Many RNAs further rely on co-existence of alternative structures, which govern their response to cellular signals. However, characterizing heterogeneous landscapes is difficult, both experimentally and computationally. Recently, structure profiling experiments have emerged as powerful and affordable structure characterization methods, which improve computational structure prediction. To date, efforts have centered on predicting one optimal structure, with much less progress made on multiple-structure prediction. Here, we report a probabilistic modeling approach that predicts a parsimonious set of co-existing structures and estimates their abundances from structure profiling data. We demonstrate robust landscape reconstruction and quantitative insights into structural dynamics by analyzing numerous data sets. This work establishes a framework for data-directed characterization of structure landscapes to aid experimentalists in performing structure-function studies
Blind MultiChannel Identification and Equalization for Dereverberation and Noise Reduction based on Convolutive Transfer Function
This paper addresses the problems of blind channel identification and
multichannel equalization for speech dereverberation and noise reduction. The
time-domain cross-relation method is not suitable for blind room impulse
response identification, due to the near-common zeros of the long impulse
responses. We extend the cross-relation method to the short-time Fourier
transform (STFT) domain, in which the time-domain impulse responses are
approximately represented by the convolutive transfer functions (CTFs) with
much less coefficients. The CTFs suffer from the common zeros caused by the
oversampled STFT. We propose to identify CTFs based on the STFT with the
oversampled signals and the critical sampled CTFs, which is a good compromise
between the frequency aliasing of the signals and the common zeros problem of
CTFs. In addition, a normalization of the CTFs is proposed to remove the gain
ambiguity across sub-bands. In the STFT domain, the identified CTFs is used for
multichannel equalization, in which the sparsity of speech signals is
exploited. We propose to perform inverse filtering by minimizing the
-norm of the source signal with the relaxed -norm fitting error
between the micophone signals and the convolution of the estimated source
signal and the CTFs used as a constraint. This method is advantageous in that
the noise can be reduced by relaxing the -norm to a tolerance
corresponding to the noise power, and the tolerance can be automatically set.
The experiments confirm the efficiency of the proposed method even under
conditions with high reverberation levels and intense noise.Comment: 13 pages, 5 figures, 5 table
Multichannel Speech Separation and Enhancement Using the Convolutive Transfer Function
This paper addresses the problem of speech separation and enhancement from
multichannel convolutive and noisy mixtures, \emph{assuming known mixing
filters}. We propose to perform the speech separation and enhancement task in
the short-time Fourier transform domain, using the convolutive transfer
function (CTF) approximation. Compared to time-domain filters, CTF has much
less taps, consequently it has less near-common zeros among channels and less
computational complexity. The work proposes three speech-source recovery
methods, namely: i) the multichannel inverse filtering method, i.e. the
multiple input/output inverse theorem (MINT), is exploited in the CTF domain,
and for the multi-source case, ii) a beamforming-like multichannel inverse
filtering method applying single source MINT and using power minimization,
which is suitable whenever the source CTFs are not all known, and iii) a
constrained Lasso method, where the sources are recovered by minimizing the
-norm to impose their spectral sparsity, with the constraint that the
-norm fitting cost, between the microphone signals and the mixing model
involving the unknown source signals, is less than a tolerance. The noise can
be reduced by setting a tolerance onto the noise power. Experiments under
various acoustic conditions are carried out to evaluate the three proposed
methods. The comparison between them as well as with the baseline methods is
presented.Comment: Submitted to IEEE/ACM Transactions on Audio, Speech and Language
Processin
Performance Analysis of Iterative Channel Estimation and Multiuser Detection in Multipath DS-CDMA Channels
This paper examines the performance of decision feedback based iterative
channel estimation and multiuser detection in channel coded aperiodic DS-CDMA
systems operating over multipath fading channels. First, explicit expressions
describing the performance of channel estimation and parallel interference
cancellation based multiuser detection are developed. These results are then
combined to characterize the evolution of the performance of a system that
iterates among channel estimation, multiuser detection and channel decoding.
Sufficient conditions for convergence of this system to a unique fixed point
are developed.Comment: To appear in the IEEE Transactions on Signal Processin
Pensamento enxuto faz ‘tempo é cérebro’ virar realidade
Intravenous rt-PA is an effective recanalizing treatment for ischemic stroke within 4 and half hours from its onset (Onset-to-Treatment [OTT]), with the best result seen in those treated within 90 minutes OTT. Yet few patients currently are treated in this time frame. From the standpoint of process improvement or a lean thinking perspective, there is a potential opportunity to reduce the time by eliminating non-value-added steps in each element of the stroke survival chain. The reduction in one time element does not necessarily shift the OTT under 90 minutes. Most likely, the reduction in OTT requires a coordinated approach to track and improve all elements of OTT, from the patient’s ability to recognize the onset of stroke up to delivery of medication. Shortening this total time should be a considered an indicator of quality improvement in acute stroke care736526530Tratamento intravenoso com rt- PA é eficaz na recanalização do acidente vascular cerebral isquêmico (AVCI) no prazo de até 4 horas e meia de seu inÃcio (OTT), com o melhor resultado visto naqueles tratados dentro de 90 minutos OTT. Apesar disso, poucos são tratados neste perÃodo de tempo. Do ponto de vista da melhoria de processos ou uma perspectiva de pensamento enxuto, há uma oportunidade potencial para reduzir o tempo ao eliminar etapas que não agregam valor em cada elemento da cadeia de sobrevivência do paciente com acidente vascular cerebral. A diminuição da OTT requer uma abordagem coordenada em conjunto para controlar e melhorar todos os elementos de OTT, a capacidade do paciente para reconhecer o inÃcio do icto até à administração da medicação. Encurtar esse tempo total deve ser um considerado um indicador da melhoria da qualidade no atendimento AVCI agudosem informaçã
Preparing Librarians to be Campus Leaders through Mapping and Integrating Information Literacy into Curriculum
Curriculum mapping is a process by which curricula are methodically examined to determine where information literacy (IL) capabilities are, or should be taught during formal coursework. Curriculum integration is the process of intentionally integrating IL capability at the points in coursework when students need to master those capabilities and competencies. During this session, librarians will develop an understanding of curriculum mapping and how to integrate IL in curricula. This knowledge prepares librarians for campus leadership, since the curriculum is the primary focus of teaching and learning and affects the entire campus.
The curriculum in higher education can be viewed as: the intended curriculum (the institution\u27s expectation of what is to be taught or learned), the offered curriculum (what teachers teach or plan to teach), and the received curriculum (the knowledge and skills that are actually learned by students via the courses).
Curriculum mapping analyzes the offered curriculum and maps it against the intended curriculum. The purpose of curriculum mapping is to identify the gaps in IL capabilities in the curriculum and to fill those gaps by integrating IL into the curriculum.
This presentation will demonstrate how to analyze the offered program curriculum; how to map it against the intended curriculum; and how to integrate IL into the curriculum. It will provide higher education faculty, librarians, and administrators with strategies for integration of information literacy into the curriculum.
Finally, the presenters will discuss a project to assess the degree to which IL is integrated into curricula. This is a collaborative project that will involve US and New Zealand colleges and universities. This project will result in cross institutional comparison data that should strengthen justifications for engaging in curriculum mapping and integration projects.
Participants will: Understand the meaning of intended curriculum and offered curriculum to gain new understanding of curriculum structure in an institution Understand how to identify potential academic courses for integrating IL across the curriculum and how to redesign course curricula by integrating IL into the curriculum Understand the institutional perspective for assessing the achievement of IL curriculum integratio
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