Unification scale vs. electroweak-triplet mass in the SU(5) + 24_F model at three loops

It was shown recently that the original SU(5) theory of Georgi and Glashow, augmented with an adjoint fermionic multiplet 24_F, can be made compatible both with neutrino masses and gauge coupling unification. In particular, the model predicts that either electroweak-triplet states are light, within the reach of the Large Hadron Collider (LHC), or proton decay will become accessible at the next generation of megaton-scale facilities. In this paper, we present the computation of the correlation function between the electroweak-triplet masses and the unification scale at the next-to-next-to-leading-order (NNLO). Such an accuracy on the theory side is necessary in order to settle the convergence of the perturbative expansion and to match the experimental precision on the determination of the electroweak gauge couplings at the Z-boson mass scale.Comment: 16 pages, 7 figures. One reference added. To appear in Phys. Rev.

On the gauge dependence of the Standard Model vacuum instability scale

After reviewing the calculation of the Standard Model one-loop effective potential in a class of linear gauges, we discuss the physical observables entering the vacuum stability analysis. While the electroweak-vacuum-stability bound on the Higgs boson mass can be formally proven to be gauge independent, the field value at which the effective potential turns negative (the so-called instability scale) is a gauge dependent quantity. By varying the gauge-fixing scheme and the gauge-fixing parameters in their perturbative domain, we find an irreducible theoretical uncertainty of at least two orders of magnitude on the scale at which the Standard Model vacuum becomes unstable.Comment: 24 pages, 4 figures. One reference added. To appear in JHE

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Oxygen Glucose Deprivation and Hyperthermia Induce Cellular Damage in Neural Precursor Cells and Immature Neurons

Hyperthermia damages both developing and adult brains, especially when it occurs after ischemia or stroke. Work presented in this dissertation used in vitro models of these stresses to investigate mechanisms underlying damage to immature neurons and neural precursors cultured from embryonic rat brain. Studies described in Chapter 2 investigated the effects of a brief, intense hyperthermic stress (30-45 min at 43ºC). This stress produced a selective depletion of nestin-immunoreactive neural precursor cells, and reduced proliferation, as evidenced by reduced BrdU incorporation into young Tuj1-immunoreactive neurons. The stress activated caspase 3, and produced multiple signs of nuclear damage as well as early and persisting mitochondrial depolarization. Cycloheximide, an inhibitor of protein synthesis, reduced cell death. All these findings suggest an apoptotic death process. Studies described in Chapter 3 used a combination of oxygen-glucose deprivation (OGD, 2 h) followed by mild 41ºC hyperthermia for 90 min (T). The combined OGDT stress reduced both survival in monolayer cultures and colony-forming ability in neurospheres. Cell death occurred gradually over 2 days, and was accompanied by caspase activation that began within 6 h post-stress. Post-stress application of cycloheximide or a general caspase inhibitor (especially qVD-OPH) reduced cell death, but specific inhibitors of caspases 2, 3, 8 or 9 were ineffective. OGDT led to upregulation of the pro-apoptotic protein Bim as well as redistribution of Bax from cytoplasm to mitochondria within 6 h. Persisting mitochondrial depolarization began within 3 h following the combined OGDT stress, but not following individual OGD or T stresses alone. These findings suggest that OGD sensitizes neural precursor cells to hyperthermia-induced damage, and that the combined OGDT stress kills neural precursors via apoptotic mechanisms that include activation of mitochondrial death pathways. Results of these studies suggest that immature neurons and neural precursors are especially vulnerable to hyperthermia-induced damage via apoptotic mechanisms. Pan-caspase inhibitors may be a promising therapeutic strategy to preserve viability of these cells following stroke with hyperthermia

The Role of the Hypothalamic–Pituitary–Adrenal Axis in Anxiety Disorders

The current understanding of the neurobiological underpinnings of all severe psychiatric disorders, including anxiety disorders, is evolving as advances in neuroscience are realized. Of particular importance is a growing body of evidence suggesting that early life trauma induces vulnerability to stress later in life, manifested by increased risk for mood and anxiety disorders The hypothalamic–pituitary–adrenal (HPA) axis is the major neuroendocrine mediator of the response to stress. This review summarizes the role of the HPA axis in stress regulation and in the pathophysiology of anxiety disorders by describing the combination of genetic factors, early life stressors, and ongoing trauma that regulate an individual’s vulnerability to syndromal anxiety disorders. Disturbances in the HPA axis across specific anxiety disorders are reviewed, including panic disorder (PD), generalized anxiety disorder (GAD), social anxiety disorder (SAD), and posttraumatic stress disorder (PTSD)

Esophagitis after Clozapine Use in a 61-Year-Old Woman with Refractory Schizophrenia

Clozapine-induced esophagitis has been rarely reported. We herein report a case of a 61-year-old woman with schizophrenia who developed hematemesis, fever, and tachycardia after the initiation of clozapine. An esophagogastroduodenoscopy showed esophageal mucosal ulcerations. Her gastrointestinal symptoms resolved with pantoprazole, allowing continuation of her clozapine treatment. We report here an unusual association of severe esophagitis with clozapine use

EMERGING AND RE-EMERGING DISEASES – THE THREAT CONTINUES

Infectious diseases have accompanied human development from the earliest times and have often influenced it greatly. Although they were considered “an endangered species” in the second half of the 20th century, they continue to pose a serious threat to individual or public health. Diagnosis technique improvement, climate changes, increased population mobility and vaccine cover decrease are only some of the factors that have contributed lately to the occurrence and fast spreading of new pathogens or to the re-emerging of diseases already considered historical. Most of these infectious agents (Zika, Ebola, Chikungunya, MERS, SARS, new influenza viruses), for which there are few therapeutic resources, were the cause for regional or global epidemic outbreaks, which generated concern among healthcare professionals and often panic in the population, as well as significant economic losses. The international and medical communities joined their forces and got financially and logistically involved, sometimes paying with their own lives, in fighting these new threats. The fast understanding of the epidemiological process, pathogenesis and development of diagnosis and prevention methods has often helped limit the spread of emerging diseases and has laid the grounds for their future control