GW190521 Mass Gap Event and the Primordial Black Hole Scenario.

The LIGO/Virgo Collaboration has recently observed GW190521, the first binary black hole merger with at least the primary component mass in the mass gap predicted by the pair-instability supernova theory. This observation disfavors the standard stellar-origin formation scenario for the heavier black hole, motivating alternative hypotheses. We show that GW190521 cannot be explained within the primordial black hole (PBH) scenario if PBHs do not accrete during their cosmological evolution, since this would require an abundance which is already in tension with current constraints. On the other hand, GW190521 may have a primordial origin if PBHs accrete efficiently before the reionization epoch.

NANOGrav Data Hints at Primordial Black Holes as Dark Matter.

The NANOGrav Collaboration has recently published strong evidence for a stochastic common-spectrum process that may be interpreted as a stochastic gravitational wave background. We show that such a signal can be explained by second-order gravitational waves produced during the formation of primordial black holes from the collapse of sizeable scalar perturbations generated during inflation. This possibility has two predictions: (i) the primordial black holes may comprise the totality of the dark matter with the dominant contribution to their mass function falling in the range (10^{-15}÷10^{-11})M_{⊙} and (ii) the gravitational wave stochastic background will be seen as well by the Laser Interferometer Space Antenna experiment.

Primordial Black Hole Dark Matter: LISA Serendipity.

There has recently been renewed interest in the possibility that the dark matter in the Universe consists of primordial black holes (PBHs). Current observational constraints leave only a few PBH mass ranges for this possibility. One of them is around 10^{-12} M_{⊙}. If PBHs with this mass are formed due to an enhanced scalar-perturbation amplitude, their formation is inevitably accompanied by the generation of gravitational waves (GWs) with frequency peaked in the mHz range, precisely around the maximum sensitivity of the LISA mission. We show that, if these primordial black holes are the dark matter, LISA will be able to detect the associated GW power spectrum. Although the GW source signal is intrinsically non-Gaussian, the signal measured by LISA is a sum of the signal from a large number of independent sources suppressing the non-Gaussianity at detection to an unobservable level. We also discuss the effect of the GW propagation in the perturbed Universe. PBH dark matter generically leads to a detectable, purely isotropic, Gaussian and unpolarized GW signal, a prediction that is testable with LISA.

[Laparoscopic hysterectomy]. / Isterectomia laparoscopica.

Our first laparoscopic hysterectomy is reported. Our report includes the following surgical actions: coagulation and dissection of the round ligament: opening of the front-large ligament; hydrodissection of the connective tissue between the two peritoneal pellicles of the large ligament; coagulation and dissection of the salpinx for tissues and uterine-ovarian vessels; dissection of the large back ligament as far as the uterines and sacrals; detachment of the bladder by means of forceps and hydrodissection; the same operations on the opposite side; visualisation of uterine vessels and dissection; dissection of uterines and sacrals; completion of the operation and removal of the ill part through the vaginal way. Laparoscopic hysterectomy or vaginal-laparoscopic hysterectomy could, in some cases, substitute abdominal hysterectomy or be less risky than vaginal operations. We point out the need for more complete laparoscopic instrumentation and more practical laparoscopic experience for surgeons and assistants.

Cutaneous metastases from carcinoma of the cervix.

Skin metastases from internal malignancies are rare, particularly those originating from carcinoma of the cervix: only 11 cases have been reported in the medical literature since 1940. We describe the case of a cutaneous metastases from a squamous-cell carcinoma of the cervix that was solitary, unusual for its location, and with the longest survival reported so far.