A Geometric Approach to Covariance Matrix Estimation and its Applications to Radar Problems

A new class of disturbance covariance matrix estimators for radar signal processing applications is introduced following a geometric paradigm. Each estimator is associated with a given unitary invariant norm and performs the sample covariance matrix projection into a specific set of structured covariance matrices. Regardless of the considered norm, an efficient solution technique to handle the resulting constrained optimization problem is developed. Specifically, it is shown that the new family of distribution-free estimators shares a shrinkagetype form; besides, the eigenvalues estimate just requires the solution of a one-dimensional convex problem whose objective function depends on the considered unitary norm. For the two most common norm instances, i.e., Frobenius and spectral, very efficient algorithms are developed to solve the aforementioned one-dimensional optimization leading to almost closed form covariance estimates. At the analysis stage, the performance of the new estimators is assessed in terms of achievable Signal to Interference plus Noise Ratio (SINR) both for a spatial and a Doppler processing assuming different data statistical characterizations. The results show that interesting SINR improvements with respect to some counterparts available in the open literature can be achieved especially in training starved regimes.Comment: submitted for journal publicatio

Blind user detection in doubly-dispersive DS/CDMA channels

In this work, we consider the problem of detecting the presence of a new user in a direct-sequence/code-division-multiple-access (DS/CDMA) system with a doubly-dispersive fading channel, and we propose a novel blind detection strategy which only requires knowledge of the spreading code of the user to be detected, but no prior information as to the time-varying channel impulse response and the structure of the multiaccess interference. The proposed detector has a bounded constant false alarm rate (CFAR) under the design assumptions, while providing satisfactory detection performance even in the presence of strong cochannel interference and high user mobility.Comment: Accepted for publication on IEEE Transactions on Signal Processin

The Retinoblastoma Family Member p107 Binds to B-MYB and Suppresses Its Autoregulatory Activity *

It was recently reported that B-MYB can overcome p107-induced growth arrest. Here we show that B-MYB autoregulation of its own transcription is specifically suppressed by p107 and transient transfection assays with p107 deletion constructs determined that the carboxyl terminus of the protein, containing the major pocket region, was associated with inhibition of B-MYB-dependent transactivation. Consistent with these results, co-immunoprecipitation studies showed that p107 interacted in vivo with B-MYB through its pocket and carboxyl terminus domain. Thus, B-MYB-dependent promotion of cell proliferation and gene transactivation might be specifically repressed by the growth suppressor p107 through direct interaction with B-MYB

Vector boson fusion at multi-TeV muon colliders

High-energy lepton colliders with a centre-of-mass energy in the multi-TeV range are currently considered among the most challenging and far-reaching future accelerator projects. Studies performed so far have mostly focused on the reach for new phenomena in lepton-antilepton annihilation channels. In this work we observe that starting from collider energies of a few TeV, electroweak (EW) vector boson fusion/scattering (VBF) at lepton colliders becomes the dominant production mode for all Standard Model processes relevant to studying the EW sector. In many cases we find that this also holds for new physics. We quantify the size and the growth of VBF cross sections with collider energy for a number of SM and new physics processes. By considering luminosity scenarios achievable at a muon collider, we conclude that such a machine would effectively be a "high-luminosity weak boson collider," and subsequently offer a wide range of opportunities to precisely measure EW and Higgs coupling as well as to discover new particles.Comment: 58 pages, 17 figures, 9 tables. A contribution to Snowmass 202

Malignant priapism due to penile metastases. Case series and literature review

Malignant priapism secondary to penile metastases is a rare condition. This term was originally used by Peacock in 1938 to describe a condition of painful induration and erection of the penis due to metastatic infiltration by a neoplasm. In the current literature there are 512 case reports. The primary tumor sites are bladder, prostate and rectum. The treatment has only palliative intent and consists of local tumor excision, penectomy, radiotherapy and chemotherapy. We present one case of malignant priapism originated from prostate cancer, and two from urothelial carcinoma of the bladder. Different approaches in diagnosis and therapy were performed. The entire three patient reported a relief of the pain following the treatment, with an improvement of their quality of life, even though it was only temporary as a palliative. Malignant priapism is a rare medical emergency. Penile/pelvis magnetic resonance imaging (MRI) scan and corporal biopsies are considered an effective method of diagnosis of the primary organ site.Malignant priapism secondary to penile metastases is a rare condition. This term was originally used by Peacock in 1938 to describe a condition of painful induration and erection of the penis due to metastatic infiltration by a neoplasm. In the current literature there are 512 case reports. The primary tumor sites are bladder, prostate and rectum. The treatment has only palliative intent and consists of local tumor excision, penectomy, radiotherapy and chemotherapy. We present one case of malignant priapism originated from prostate cancer, and two from urothelial carcinoma of the bladder. Different approaches in diagnosis and therapy were performed. The entire three patient reported a relief of the pain following the treatment, with an improvement of their quality of life, even though it was only temporary as a palliative. Malignant priapism is a rare medical emergency. Penile/pelvis magnetic resonance imaging (MRI) scan and corporal biopsies are considered an effective method of diagnosis of the primary organ site