Deep Metric Learning via Facility Location

Learning the representation and the similarity metric in an end-to-end fashion with deep networks have demonstrated outstanding results for clustering and retrieval. However, these recent approaches still suffer from the performance degradation stemming from the local metric training procedure which is unaware of the global structure of the embedding space. We propose a global metric learning scheme for optimizing the deep metric embedding with the learnable clustering function and the clustering metric (NMI) in a novel structured prediction framework. Our experiments on CUB200-2011, Cars196, and Stanford online products datasets show state of the art performance both on the clustering and retrieval tasks measured in the NMI and Recall@K evaluation metrics.Comment: Submission accepted at CVPR 201

RF communication with implantable wireless device: effects of beating heart on performance of miniature antenna

The frequency response of an implantable antenna is key to the performance of a wireless implantable sensor. If the antenna detunes significantly, there are substantial power losses resulting in loss of accuracy. One reason for detuning is because of a change in the surrounding environment of an antenna. The pulsating anatomy of the human heart constitutes such a changing environment, so detuning is expected but this has not been quantified dynamically before. Four miniature implantable antennas are presented (two different geometries) along with which are placed within the heart of living swine the dynamic reflection coefficients. These antennas are designed to operate in the short range devices frequency band (863-870 MHz) and are compatible with a deeply implanted cardiovascular pressure sensor. The measurements recorded over 27 seconds capture the effects of the beating heart on the frequency tuning of the implantable antennas. When looked at in the time domain, these effects are clearly physiological and a combination of numerical study and posthumous autopsy proves this to be the case, while retrospective simulation confirms this hypothesis. The impact of pulsating anatomy on antenna design and the need for wideband implantable antennas is highlighted

The contribution of star-forming galaxies to the cosmic radio background

Recent measurements of the temperature of the sky in the radio band, combined with literature data, have convincingly shown the existence of a cosmic radio background with an amplitude of $\sim 1$ K at 1 GHz and a spectral energy distribution that is well described by a power law with index $\alpha \simeq -0.6$. The origin of this signal remains elusive, and it has been speculated that it could be dominated by the contribution of star-forming galaxies at high redshift \change{if the far infrared-radio correlation $q(z)$ evolved} in time. \change{We fit observational data from several different experiments by the relation $q(z) \simeq q_0 - \beta \log(1+z)$ with $q_0 = 2.783 \pm 0.024$ and $\beta = 0.705 \pm 0.081$ and estimate the total radio emission of the whole galaxy population at any given redshift from the cosmic star formation rate density at that redshift. It is found that} star-forming galaxies can only account for $\sim$13 percent of the observed intensity of the cosmic radio background.Comment: 5 pages, 3 figure

Deletion of the L-type calcium channel Ca V 1.3 but not Ca V 1.2 results in a diminished sAHP in mouse CA1 pyramidal neurons

Trains of action potentials in CA1 pyramidal neurons are followed by a prolonged calcium-dependent postburst afterhyperpolarization (AHP) that serves to limit further firing to a sustained depolarizing input. A reduction in the AHP accompanies acquisition of several types of learning and increases in the AHP are correlated with age-related cognitive impairment. The AHP develops primarily as the result of activation of outward calcium-activated potassium currents; however, the precise source of calcium for activation of the AHP remains unclear. There is substantial experimental evidence suggesting that calcium influx via voltage-gated L-type calcium channels (L-VGCCs) contributes to the generation of the AHP. Two L-VGCC subtypes are predominately expressed in the hippocampus, Ca V 1.2 and Ca V 1.3; however, it is not known which L-VGCC subtype is involved in generation of the AHP. This ambiguity is due in large part to the fact that at present there are no subunit-specific agonists or antagonists. Therefore, using mice in which the gene encoding Ca V 1.2 or Ca V 1.3 was deleted, we sought to determine the impact of alterations in levels of these two L-VCGG subtypes on neuronal excitability. No differences in any AHP measure were seen between neurons from Ca V 1.2 knockout mice and controls. However, the total area of the AHP was significantly smaller in neurons from Ca V 1.3 knockout mice as compared with neurons from wild-type controls. A significant reduction in the amplitude of the AHP was also seen at the 1 s time point in neurons from Ca V 1.3 knockout mice as compared with those from controls. Reductions in both the area and 1 s amplitude suggest the involvement of calcium influx via Ca V 1.3 in the slow AHP (sAHP). Thus, the results of our study demonstrate that deletion of Ca V 1.3, but not Ca V 1.2, significantly impacts the generation of the sAHP. © 2009 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79416/1/20728_ftp.pd

Inhibition of HIV-1 infection by aqueous extracts of Prunella vulgaris L.

<p>Abstract</p> <p>Background</p> <p>The mint family (Lamiaceae) produces a wide variety of constituents with medicinal properties. Several family members have been reported to have antiviral activity, including lemon balm (<it>Melissa officinalis </it>L.), sage (<it>Salvia </it>spp.), peppermint (<it>Mentha </it>× <it>piperita </it>L.), hyssop (<it>Hyssopus officinalis </it>L.), basil (<it>Ocimum </it>spp.) and self-heal (<it>Prunell</it>a <it>vulgaris </it>L.). To further characterize the anti-lentiviral activities of <it>Prunella vulgaris</it>, water and ethanol extracts were tested for their ability to inhibit HIV-1 infection.</p> <p>Results</p> <p>Aqueous extracts contained more anti-viral activity than did ethanol extracts, displaying potent antiviral activity against HIV-1 at sub μg/mL concentrations with little to no cellular cytotoxicity at concentrations more than 100-fold higher. Time-of-addition studies demonstrated that aqueous extracts were effective when added during the first five hours following initiation of infection, suggesting that the botanical constituents were targeting entry events. Further analysis revealed that extracts inhibited both virus/cell interactions and post-binding events. While only 40% inhibition was maximally achieved in our virus/cell interaction studies, extract effectively blocked post-binding events at concentrations similar to those that blocked infection, suggesting that it was targeting of these latter steps that was most important for mediating inhibition of virus infectivity.</p> <p>Conclusions</p> <p>We demonstrate that aqueous <it>P. vulgaris </it>extracts inhibited HIV-1 infectivity. Our studies suggest that inhibition occurs primarily by interference of early, post-virion binding events. The ability of aqueous extracts to inhibit early events within the HIV life cycle suggests that these extracts, or purified constituents responsible for the antiviral activity, are promising microbicides and/or antivirals against HIV-1.</p

A Case of Atrophoderma of Pasini and Pierini Associated with Borrelia burgdorferi Infection Successfully Treated with Oral Doxycycline

Atrophoderma of Pasini and Pierini is a form of dermal atrophy that manifests as either single or multiple, sharply demarcated, hyperpigmented, non-indurated patches. These patches are marked by a slight depression of the skin, with an abrupt edge (i.e., the "cliff-drop" borders), usually located on the backs of adolescents or young adults. The pathophysiology of the disease is unknown, but some authors have suggested a role of Borrelia burgdorferi infection. A 35-year-old woman visited our department because of asymptomatic, hypopigmented, depressed patches on her chest and back lasting for three months. Laboratory evaluations were normal, except for positive serum antibodies to Borrelia burgdorferi. Histologic examination revealed a significantly decreased thickness of the dermis. The patient underwent treatment with oral doxycycline 200 mg/day for six weeks, after which the depth of depression was improved. Herein, we report a case of atrophoderma of Pasini and Pierini, associated with Borrelia burgdorferi infection, successfully treated with oral doxycycline

Differential regulation of immune responses and macrophage/neuron interactions in the dorsal root ganglion in young and adult rats following nerve injury

Background: Neuropathic pain is an apparently spontaneous experience triggered by abnormal physiology of the peripheral or central nervous system, which evolves with time. Neuropathic pain arising from peripheral nerve injury is characterized by a combination of spontaneous pain, hyperalgesia and allodynia. There is no evidence of this type of pain in human infants or rat pups; brachial plexus avulsion, which causes intense neuropathic pain in adults, is not painful when the injury is sustained at birth. Since infants are capable of nociception from before birth and display both acute and chronic inflammatory pain behaviour from an early neonatal age, it appears that the mechanisms underlying neuropathic pain are differentially regulated over a prolonged postnatal period.Results: We have performed a microarray analysis of the rat L4/L5 dorsal root ganglia (DRG), 7 days post spared nerve injury, a model of neuropathic pain. Genes that are regulated in adult rats displaying neuropathic behaviour were compared to those regulated in young rats (10 days old) that did not show the same neuropathic behaviour. The results show a set of genes, differentially regulated in the adult DRG, that are principally involved in immune system modulation. A functional consequence of this different immune response to injury is that resident macrophages cluster around the large A sensory neuron bodies in the adult DRG seven days post injury, whereas the macrophages in young DRG remain scattered evenly throughout the ganglion, as in controls.Conclusions: The results show, for the first time, a major difference in the neuroimmune response to nerve injury in the dorsal root ganglion of young and adult rats. Differential analysis reveals a new set of immune related genes in the ganglia, that are differentially regulated in adult neuropathic pain, and that are consistent with the selective activation of macrophages around adult, but not young large A sensory neurons post injury. These differences may contribute to the reduced incidence of neuropathic pain in infants