638 research outputs found
Counterterms vs. Dualities
We investigate and clarify the mutual compatibility of the higher order
corrections arising in supergravity and string theory effective actions and the
non-linear duality symmetries of these theories. Starting from a conventional
tree level action leading to duality invariant equations of motion, we show how
to accommodate duality invariant counterterms given as functionals of both
electric and magnetic fields in a perturbative expansion, and to deduce from
them a non-polynomial bona fide action satisfying the Gaillard-Zumino
constraint. There exists a corresponding consistency constraint in the
non-covariant Henneaux-Teitelboim formalism which ensures that one can always
restore diffeomorphism invariance by perturbatively solving this functional
identity. We illustrate how this procedure works for the R^2 \nabla F \nabla F
and F^4 counterterms in Maxwell theory.Comment: 15 page
Laughing Hyena Distillery: Extracting Compact Recurrences From Convolutions
Recent advances in attention-free sequence models rely on convolutions as
alternatives to the attention operator at the core of Transformers. In
particular, long convolution sequence models have achieved state-of-the-art
performance in many domains, but incur a significant cost during
auto-regressive inference workloads -- naively requiring a full pass (or
caching of activations) over the input sequence for each generated token --
similarly to attention-based models. In this paper, we seek to enable compute and memory cost per token in any pre-trained long convolution
architecture to reduce memory footprint and increase throughput during
generation. Concretely, our methods consist in extracting low-dimensional
linear state-space models from each convolution layer, building upon rational
interpolation and model-order reduction techniques. We further introduce
architectural improvements to convolution-based layers such as Hyena: by
weight-tying the filters across channels into heads, we achieve higher
pre-training quality and reduce the number of filters to be distilled. The
resulting model achieves 10x higher throughput than Transformers and 1.5x
higher than Hyena at 1.3B parameters, without any loss in quality after
distillation
Progress in pediatric rheumatology: apprehend the opportunities of the future without forgetting the lessons from the past
Neurogenesis Drives Stimulus Decorrelation in a Model of the Olfactory Bulb
The reshaping and decorrelation of similar activity patterns by neuronal
networks can enhance their discriminability, storage, and retrieval. How can
such networks learn to decorrelate new complex patterns, as they arise in the
olfactory system? Using a computational network model for the dominant neural
populations of the olfactory bulb we show that fundamental aspects of the adult
neurogenesis observed in the olfactory bulb -- the persistent addition of new
inhibitory granule cells to the network, their activity-dependent survival, and
the reciprocal character of their synapses with the principal mitral cells --
are sufficient to restructure the network and to alter its encoding of odor
stimuli adaptively so as to reduce the correlations between the bulbar
representations of similar stimuli. The decorrelation is quite robust with
respect to various types of perturbations of the reciprocity. The model
parsimoniously captures the experimentally observed role of neurogenesis in
perceptual learning and the enhanced response of young granule cells to novel
stimuli. Moreover, it makes specific predictions for the type of odor
enrichment that should be effective in enhancing the ability of animals to
discriminate similar odor mixtures
A new procedure to measure children's reading speed and accuracy in Italian
Impaired readers in primary school should be early
recognized, in order to asses a targeted intervention within the
school and to start a teaching that respects the difficulties in
learning to read, to write and to perform calculations. Screening
procedures inside the primary schools aimed at detecting children
with difficulties in reading, are of fundamental importance for
guaranteeing an early identification of dyslexic children and
reducing both the primary negative effects - on learning - and the
secondary negative effects - on the development of the personality
- of this disturbance. In this study we propose a new screening
procedure measuring reading speed and accuracy. This procedure is
very fast (it is exactly one minute long), simple, cheap and can
be provided by teachers without technical knowledge. On the
contrary, most of the currently used diagnostic tests, are about
10 minutes long and must be provided by experts. These two major
flaws prevent the widespread use of these tests. On the basis of
the results obtained in a survey on about 1500 students attending
primary school in Italy, we investigate the relationships between
variables used in the screening procedure and variables measuring
speed and accuracy in the currently used diagnostic tests in
Italy. Then, we analyze the validity of the screening procedure
from a statistical point of view and with an explorative factor
analysis we show that reading speed and accuracy seem to be two
separate symptoms of the dyslexia phenomenon
Prognostic value of physicians' assessment of compliance regarding all-cause mortality in patients with type 2 diabetes: primary care follow-up study
BACKGROUND: Whether the primary care physician's assessment of patient compliance is a valuable prognostic marker to identify patients who are at increased risk of death, or merely reflects measurement of various treatment parameters such as HbA(1C )or other laboratory markers is unclear. The objective of this prospective cohort study was to investigate the prognostic value of the physicians' assessment of patient compliance and other factors with respect to all-cause mortality during a one year follow-up period. METHODS: A prospective cohort study was conducted among 1014 patients with type 2 diabetes aged 40 and over (mean age 69 years, SD 10.4, 45% male) who were under medical treatment in 11 participating practices of family physicians and internists working in primary care in a defined region in South Germany between April and June 2000. Baseline data were gathered from patients and physicians by standardized questionnaire. The physician's assessment of patient compliance was assessed by means of a 4-point Likert scale (very good, rather good, rather bad, very bad). In addition, we carried out a survey among physicians by means of a questionnaire to find out which aspects for the assessment of patient compliance were of importance to make this assessment. Active follow-up of patients was conducted after one year to determine mortality. RESULTS: During the one year follow-up 48 (4.7%) of the 1014 patients died. Among other factors such as patient type (patients presenting at office, nursing home or visited patients), gender, age and a history of macrovascular disease, the physician's assessment of patient compliance was an important predictor of all-cause mortality. Patients whose compliance was assessed by the physician as "very bad" (6%) were significantly more likely to die during follow-up (OR = 2.67, 95% CI 1.02â6.97) after multivariable adjustment compared to patients whose compliance was assessed as "rather good" (45%) or "very good" (18%). The HbA(1C)-value and the cholesterol level at baseline showed no statistically significant association with all-cause mortality. According to our survey for most of the physicians self-acceptance of disease, treatment adherence, patient's interest in physician's explanations, attendance at appointments, a good self-management, and a good physician-patient relationship were key elements in the assessment of patient compliance. CONCLUSION: The primary care physician's assessment of patient compliance is a valuable prognostic marker for mortality among patients with type 2 diabetes. Identification of patients in need of improved compliance may help to target preventive measures
In vitro evaluation of various bioabsorbable and nonresorbable barrier membranes for guided tissue regeneration
<p>Abstract</p> <p>Background</p> <p>Different types of bioabsorbable and nonresorbable membranes have been widely used for guided tissue regeneration (GTR) with its ultimate goal of regenerating lost periodontal structures. The purpose of the present study was to evaluate the biological effects of various bioabsorbable and nonresorbable membranes in cultures of primary human gingival fibroblasts (HGF), periodontal ligament fibroblasts (PDLF) and human osteoblast-like (HOB) cells <it>in vitro</it>.</p> <p>Methods</p> <p>Three commercially available collagen membranes [TutoDent<sup>Ÿ </sup>(TD), Resodont<sup>Ÿ </sup>(RD) and BioGide<sup>Ÿ </sup>(BG)] as well as three nonresorbable polytetrafluoroethylene (PTFE) membranes [ACE (AC), Cytoplast<sup>Ÿ </sup>(CT) and TefGen-FD<sup>Ÿ </sup>(TG)] were tested. Cells plated on culture dishes (CD) served as positive controls. The effect of the barrier membranes on HGF, PDLF as well as HOB cells was assessed by the Alamar Blue fluorometric proliferation assay after 1, 2.5, 4, 24 and 48 h time periods. The structural and morphological properties of the membranes were evaluated by scanning electron microscopy (SEM).</p> <p>Results</p> <p>The results showed that of the six barriers tested, TD and RD demonstrated the highest rate of HGF proliferation at both earlier (1 h) and later (48 h) time periods (<it>P </it>< 0.001) compared to all other tested barriers and CD. Similarly, TD, RD and BG had significantly higher numbers of cells at all time periods when compared with the positive control in PDLF culture (<it>P </it>†0.001). In HOB cell culture, the highest rate of cell proliferation was also calculated for TD at all time periods (<it>P </it>< 0.001). SEM observations demonstrated a microporous structure of all collagen membranes, with a compact top surface and a porous bottom surface, whereas the nonresorbable PTFE membranes demonstrated a homogenous structure with a symmetric dense skin layer.</p> <p>Conclusion</p> <p>Results from the present study suggested that GTR membrane materials, per se, may influence cell proliferation in the process of periodontal tissue/bone regeneration. Among the six membranes examined, the bioabsorbable membranes demonstrated to be more suitable to stimulate cellular proliferation compared to nonresorbable PTFE membranes.</p
TGF-Ă induces miR-100 and miR-125b but blocks let-7a through LIN28B controlling PDAC progression.
Abstract
TGF-Ă/Activin induces epithelial-to-mesenchymal transition (EMT) and stemness in pancreatic ductal adenocarcinoma (PDAC). However, the microRNAs (miRNAs) regulated during this response have remained yet undetermined. Here, we show that TGF-Ă transcriptionally induces MIR100HG lncRNA, containing miR-100, miR-125b and let-7a in its intron, via SMAD2/3. Interestingly, we find that although the pro-tumourigenic miR-100 and miR-125b accordingly increase, the amount of anti-tumourigenic let-7a is unchanged, as TGF-Ă also induces LIN28B inhibiting its maturation. Notably, we demonstrate that inactivation of miR-125b or miR-100 affects the TGF-Ă-mediated response indicating that these miRNAs are important TGF-Ă effectors. We integrated AGO2-RIP-seq with RNA-seq to identify the global regulation exerted by these miRNAs in PDAC cells. Transcripts targeted by miR-125b and miR-100 significantly overlap and mainly inhibit p53 and cell-cell junctionsâ pathways. Together, we uncover that TGF-Ă induces an lncRNA, whose encoded miRNAs, miR-100, let-7a and miR-125b, play opposing roles in controlling PDAC tumourigenesis
Visualizing early splenic memory CD8+ T cells reactivation against intracellular bacteria in the mouse
International audienceMemory CD8(+) T cells represent an important effector arm of the immune response in maintaining long-lived protective immunity against viruses and some intracellular bacteria such as Listeria monocytogenes (L.m). Memory CD8(+) T cells are endowed with enhanced antimicrobial effector functions that perfectly tail them to rapidly eradicate invading pathogens. It is largely accepted that these functions are sufficient to explain how memory CD8(+) T cells can mediate rapid protection. However, it is important to point out that such improved functional features would be useless if memory cells were unable to rapidly find the pathogen loaded/infected cells within the infected organ. Growing evidences suggest that the anatomy of secondary lymphoid organs (SLOs) fosters the cellular interactions required to initiate naive adaptive immune responses. However, very little is known on how the SLOs structures regulate memory immune responses. Using Listeria monocytogenes (L.m) as a murine infection model and imaging techniques, we have investigated if and how the architecture of the spleen plays a role in the reactivation of memory CD8(+) T cells and the subsequent control of L.m growth. We observed that in the mouse, memory CD8(+) T cells start to control L.m burden 6 hours after the challenge infection. At this very early time point, L.m-specific and non-specific memory CD8(+) T cells localize in the splenic red pulp and form clusters around L.m infected cells while naĂŻve CD8(+) T cells remain in the white pulp. Within these clusters that only last few hours, memory CD8(+) T produce inflammatory cytokines such as IFN-gamma and CCL3 nearby infected myeloid cells known to be crucial for L.m killing. Altogether, we describe how memory CD8(+) T cells trafficking properties and the splenic micro-anatomy conjugate to create a spatio-temporal window during which memory CD8(+) T cells provide a local response by secreting effector molecules around infected cells
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