Learning Irreducible Representations of Noncommutative Lie Groups

Recent work has constructed neural networks that are equivariant to continuous symmetry groups such as 2D and 3D rotations. This is accomplished using explicit group representations to derive the equivariant kernels and nonlinearities. We present two contributions motivated by frontier applications of equivariance beyond rotations and translations. First, we relax the requirement for explicit Lie group representations, presenting a novel algorithm that finds irreducible representations of noncommutative Lie groups given only the structure constants of the associated Lie algebra. Second, we demonstrate that Lorentz-equivariance is a useful prior for object-tracking tasks and construct the first object-tracking model equivariant to the Poincar\'e group.Comment: 15 pages, 5 figure

Prefrontal-Hippocampal Interactions

Long-term memories are established in the neocortex under the influence of hippocampal activity. The precise circuit mechanisms underlying this process, however, remain poorly understood. According to the dominant paradigm, memories are formed in two stages: first, neocortical activity during awake behavior embeds traces in hippocampal circuits; second, spontaneous hippocampal activity during offline periods, such as sleep, drives synaptic changes across cortical circuits so as to produce a stable, long-term memory trace. Evidence for this two-stage model at the level of neural activity, however, is incomplete. In this thesis we study interactions between the hippocampus and medial prefrontal cortex (mPFC) to elucidate the basic principles of how these brain circuits work in concert in support of long-term memory. Using recordings of single-unit actvity from multi-tetrode arrays in the hippocampus and mPFC of freely behaving rats, we performed two sets of experiments, each addressing one stage of the two-stage model. First, during awake behavior, we find a class of mPFC cells whose firing reflects the strength of a learned association and show that these tend to be strongly modulated by the hippocampus. Second, during sleep, we identify precise spike timing relationships between single mPFC and hippocampal cells that are consistent with information flow from the hippocampus to the prefrontal cortex, and show that these timing relationships are highly dependent on sleep stage. Taken together, these results provide key constraints on the circuit mechanisms of long-term memory formation

Colite histiocitica ulcerativa em um cão : relato de caso

A colite histiocitica ulcerativa (CHU) é uma enteropatia crônica, de ocorrência principalmente em cães da raça Boxer, que consiste na infiltração inflamatória de macrófagos na parede do cólon em decorrência da invasão da bactéria Escherichia coli. Sua ocorrência é rara e, apesar da enrofloxacina ser o antimicrobiano de escolha, a resposta ao mesmo pode variar. O objetivo do presente trabalho foi relatar os aspectos clínicos e terapêuticos da colite histiocítica ulcerativa em um cão da raça Boxer. Foi atendido um cão, Boxer, com oito meses de idade com queixa de vômitos, diarreia, perda de peso e hematoquezia desde os dois meses de idade, com intensificação dos sinais havia três dias. Foram solicitados exames hematológicos que encontraram-se normais. Ainda, solicitou-se ultrassonografia abdominal que revelou espessamento de parede intestinal e o exame parasitológico de fezes apresentou Entamoeba spp., Ancylostoma sp. e, Strongyloides sp. Foi prescrito Nitazoxanida (50 mg/kg, dose única) associado a Fembendazol (50 mg/kg, SID, 5 dias). O animal retornou apresentando piora clínica e então foi internado, estabilizado e encaminhado para procedimento de endoscopia digestiva alta e baixa. A colonoscopia, foi observado hiperemia, edema, irregularidade e friabilidade da mucosa dos cólons compatíveis com processo inflamatório crônico. Foram coletados fragmentos para análise histopatológica que corroborou o diagnóstico de colite histiocítica ulcerativa. Iniciaram-se a terapia com enrofloxacina (5 mg/kg, BID, 30 dias) associada a probiótico (4 g, VO, SID, 10 dias). Após 45 dias de tratamento, o animal retornou sem alterações gastrointestinais e com melhora no escore corporal. Após 17 meses de terapia contínua com enrofloxacina, foi suspenso o antimicrobiano e introduzido dieta rica em fibras. Atualmente o paciente encontra-se sem sinais clínicos e com excelente qualidade de vida.Histiocytic ulcerative colitis is a chronic enteropathy, which occurs mainly in Boxer dogs, it consists of inflammatory infiltration of macrophages in the colon wall due to invasion of Escherichia colli. Its occurrence is rare, and despite enrofloxacin being the antibiotic of choice, the response to it may vary. The purpose of the present paper is to report the clinical and therapeutical aspects of histiocytic ulcerative colitis in a Boxer dog. An eight months old boxer dog was attended at the UFRGS veterinary clinical hospital, presenting clinical signs such as vomiting, diarrhea, weight loss and hematochezia since two months of age, with intensification of the clinical signs three days before the presentation. Was requested blood work, which was normal. Additionally, abdominal ultrasound was requested which revealed intestinal wall thickening and fecal test that showed Entamoeba spp., Ancylostoma sp. and Strongyloides sp.. It was prescribed Nitazoxanide (50mg/kg, single dose), associated with Fembendazole (50mg/kg, SID, 5 days). The patient returned presenting worsening of the clinical signs and was then hospitalized, stabilized and submitted to high and low digestive endoscopy. In the colonoscopy was observed hyperemia, edema, irregularity and friability of the colonic mucosa compatible with chronic inflammatory process. Fragments where collected for histopathological analysis that corroborated the diagnosis of histiocytic ulcerative colitis. Therapy with enrofloxacin (5mg/kg, BID) associated with probiotic (4g, SID, 10 days) was initiated. After 45 days of treatment, the patient came back with no gastrointestinal sings and improvement of body condition score. After 17 months of uninterrupted treatment with enrofloxacin it was discontinued after introduction of high fiber diet. The patient is currently with no clinical signs and an excellent quality of life

State-dependent spike-timing relationships between hippocampal and prefrontal circuits during sleep

Cortico-hippocampal interactions during sleep are believed to reorganize neural circuits in support of memory consolidation. However, spike-timing relationships across cortico-hippocampal networks—key determinants of synaptic changes—are poorly understood. Here we show that cells in prefrontal cortex fire consistently within 100 ms after hippocampal cells in naturally sleeping animals. This provides evidence at the single cell-pair level for highly consistent directional interactions between these areas within the window of plasticity. Moreover, these interactions are state dependent: they are driven by hippocampal sharp-wave/ripple (SWR) bursts in slow-wave sleep (SWS) and are sharply reduced during REM sleep. Finally, prefrontal responses are nonlinear: as the strength of hippocampal bursts rises, short-latency prefrontal responses are augmented by increased spindle band activity and a secondary peak ∼100 ms later. These findings suggest that SWR events are atomic units of hippocampal-prefrontal communication during SWS and that the coupling between these areas is highly attenuated during REM sleep

Tympanic membrane retractions in patients with Williams Syndrome : a controlled study

Introduction The role of elastin in tympanic retractions and chronic otitis media is not well established. Williams Syndrome (WS), a pathology related to a mutation in the elastin gene, could generate tympanic retractions. Objective To compare the prevalence of tympanic retractions among patients with WS and controls. Methods WS patients (n = 43 ears) and controls (n = 130 ears) were evaluated by digital otoscopic examination and the degree of tympanic membrane retraction was classified by 2 blinded experienced otolaryngologists. Results The agreement rate between the evaluators was 71.1% for pars tensa and 65% for pars flaccida retraction (p < 0.001). The pars tensa and pars flaccida retractions are present in patients with WS after an adjusted residue of respectively - 2.8 and - 2.6 (p = 0.011 and p = 0.022) compared with controls. Conclusions Tympanic membrane retractions are not more common in the WS group when compared with controls

nGraph-HE: A Graph Compiler for Deep Learning on Homomorphically Encrypted Data

Homomorphic encryption (HE)---the ability to perform computation on encrypted data---is an attractive remedy to increasing concerns about data privacy in deep learning (DL). However, building DL models that operate on ciphertext is currently labor-intensive and requires simultaneous expertise in DL, cryptography, and software engineering. DL frameworks and recent advances in graph compilers have greatly accelerated the training and deployment of DL models to various computing platforms. We introduce nGraph-HE, an extension of nGraph, Intel\u27s DL graph compiler, which enables deployment of trained models with popular frameworks such as TensorFlow while simply treating HE as another hardware target. Our graph-compiler approach enables HE-aware optimizations-- implemented at compile-time, such as constant folding and HE-SIMD packing, and at run-time, such as special value plaintext bypass. Furthermore, nGraph-HE integrates with DL frameworks such as TensorFlow, enabling data scientists to benchmark DL models with minimal overhead

nGraph-HE2: A High-Throughput Framework for Neural Network Inference on Encrypted Data

In previous work, Boemer et al. introduced nGraph-HE, an extension to the Intel nGraph deep learning (DL) compiler, that en- ables data scientists to deploy models with popular frameworks such as TensorFlow and PyTorch with minimal code changes. However, the class of supported models was limited to relatively shallow networks with polynomial activations. Here, we introduce nGraph-HE2, which extends nGraph-HE to enable privacy-preserving inference on standard, pre-trained models using their native activation functions and number fields (typically real numbers). The proposed framework leverages the CKKS scheme, whose support for real numbers is friendly to data science, and a client-aided model to compute activation functions. We first present CKKS-specific optimizations, enabling a 3x-88x runtime speedup for scalar encoding, and doubling the throughput through a novel use of CKKS plaintext packing into complex numbers. Second, we optimize ciphertext-plaintext addition and multiplication, yielding 2.6x- 4.2x runtime speedup. Third, we present two graph-level optimizations: lazy rescaling and depth-aware encoding. Together, these optimizations enable state-of-the-art throughput of 1,998 images/s on the CryptoNets network. We also present homomorphic evaluation of (to our knowledge) the largest network to date, namely, pre-trained MobileNetV2 models on the ImageNet dataset, with 60.4%/82.7% top-1/top-5 accuracy and an amortized runtime of 381 ms/image

Petrografia das rochas vulcânicas do Pontal Hardy, Ilha Greenwich, arquipélago Shetland do Sul, Antártica : resultados preliminares

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