Caudal regression syndrome is a rare disorder of distal spinal segments affecting the development of the spinal cord, with attendant sequelae. Intelligence is preserved. The exact etiology is elusive, though maternal diabetes, genetic factors, and hypoperfusion might play roles. Recently, the role of teratogens has been studied in animal models. Treatment is difficult, multidisciplinary, and largely supportive. Lower limb deformities with sensory and motor loss and neurogenic bladder call for intensive and long-term attention.

The Coronavirus disease-2019 (COVID-19) pandemic is an unprecedented health care crisis and has led to over 1.5 million deaths worldwide. The risk of severe COVID-19 and mortality is markedly raised in patients with cancer, prompting several collaborative groups to issue guidelines to mitigate the risk of infection by delaying or de-escalating immunosuppressive therapy. However, delayed therapy is often not feasible for patients requiring treatment for acute leukemia or stem cell transplantation. We provide a focused review of the recommendations and evidence for managing this high-risk group of patients while minimizing the risk of COVID-19 infection, and provide a small snapshot of treatment data from our center.

We constructed rephasing invariant measures of CP violation with elements of the neutrino mass matrix, in the basis in which the charged lepton mass matrix is diagonal. We discuss some examples of neutrino mass matrices with texture zeroes, where the present approach is applicable and demonstrate how it simplifies an analysis of CP violation. We applied our approach to study CP violation in all the phenomenologically acceptable 3-generation two-zero texture neutrino mass matrices and shown that in any of these cases there is only one CP phase which contributes to the neutrino oscillation experiment and there are no Majorana phases.Comment: 19 page

An attractive explanation for non-zero neutrino masses and small matter antimatter asymmetry of the present Universe lies in "leptogenesis". At present the size of the lepton asymmetry is precisely known, while the sign is not known yet. In this work we determine the sign of this asymmetry in the framework of two right handed neutrino models by relating the leptogenesis phase(s) with the low energy CP violating phases appearing in the leptonic mixing matrix. It is shown that the knowledge of low energy lepton number violating re-phasing invariants can indeed determine the sign of the present matter antimatter asymmetry of the Universe and hence indirectly probing the light physical neutrinos to be Majorana type.

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We implemented the neutrino dark energy (νDE) proposal in a left-right symmetric model. Unlike earlier models of mass varying neutrinos, in the present model the mass parameter that depends on the scalar field (acceleron) remains very light naturally. The required neutrino masses then predicts the U (1)R breaking scale to be in the TeV range, providing new signals for LHC. Compared to all other νDE proposals, this model has the added advantage that it can also be embedded into a grand unified theory. In this scenario leptogenesis occurs through decays of scalars at very high energy.Present observations reveal that the dark energy ∼ (3 × 10 −3 eV) 4 [1] contributes about 70% to the total density of our universe. Since the only known physics around this scale is the neutrino mass, there are now attempts to relate the origin of the dark energy with the neutrino masses [2,3,4]. This connection is based on the idea of quintessence [5], and have several interesting consequences [6,7].In the original model of neutrino dark energy (νDE) or the mass varying neutrinos (mavans) [2,3,4], the standard model is extended by including singlet righthanded neutrinos N i , i = 1, 2, 3, and giving a Majorana mass to the neutrinos which varies with a scalar field, the acceleron. This model was not complete and several problems were pointed out [3,8]. Some of the problems have been solved in subsequent works [9,10], but more studies are required to make this model fully consistent. The main motivation of the present article is to justify the very low scale entering in this model naturally, embed this idea into a left-right symmetric model and also in grand unified theories. Since the right-handed neutrinos are not very heavy, leptogenesis occurs through scalar decays.In the νDE models, the Majorana masses of the righthanded neutrinos varies with the acceleron field and that relates the scale of dark energy with the light neutrino masses. Naturalness requires the Majorana masses of the right-handed neutrinos also to be in the range of eV, so the main motivation of the seesaw mechanism is lost. The smallness of the light neutrino masses cannot be attributed to a large lepton number violating mass scale in the theory. In this νDE model, the neutrino Dirac masses cannot be made to vary with the acceleron field, since that will then allow coupling of the acceleron field with the charged leptons and a natural scale for the dark energy will then be the mass of the heaviest charged lepton. For the same reason, this mechanism cannot be embedded into a left-right symmetric model, in which the SU (2) R group relates the right-handed neutrinos to the right-handed charged leptons.The problem with the smallness of the mass parameter that depends on the acceleron field can be softened in the νDE models with triplet Higgs scalars [10]. In these models the standard model is extended to include triplet Higgs scalars. In any phenomenologically consistent triplet Higgs scalar model, lepton number is violated explicitly by a trilinear scalar couplings of ...

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