Phenomenology of Light Sneutrino Dark Matter in cMSSM/mSUGRA with Inverse Seesaw

We study the possibility of a light Dark Matter (DM) within a constrained Minimal Supersymmetric Standard Model (cMSSM) framework augmented by a SM singlet-pair sector to account for the non-zero neutrino masses by inverse seesaw mechanism. Working within a 'hybrid' scenario with the MSSM sector fixed at high scale and the singlet neutrino sector at low scale, we find that, contrary to the case of the usual cMSSM where the neutralino DM cannot be very light, we can have a light sneutrino DM with mass below 100 GeV satisfying all the current experimental constraints from cosmology, collider as well as low-energy experiments. We also note that the supersymmetric inverse seesaw mechanism with sneutrino as the lightest supersymmetric partner can have enhanced same-sign dilepton final states with large missing transverse energy (mET) coming from the gluino- and squark-pair as well as the squark-gluino associated productions and their cascade decay through charginos. We present a collider study for the same-sign dilepton+jets+mET signal in this scenario and propose some distinctions with the usual cMSSM. We also comment on the implications of such a light DM scenario on the invisible decay width of an 125 GeV Higgs boson.Comment: 24 pages, 4 figures, 7 tables; matches published versio

Cryptic speciation and chromosomal repatterning in the South African climbing mice Dendromus (Rodentia, Nesomyidae)

We evaluate the intra- and interspecific diversity in the four South African rodent species of the genus Dendromus. The molecular phylogenetic analysis on twenty-three individuals have been conducted on a combined dataset of nuclear and mitochondrial markers. Moreover, the extent and processes underlying chromosomal variation, have been investigated on three species by mean of G-, C-bands, NORs and Zoo-FISH analysis. The molecular analysis shows the presence of six monophyletic lineages corresponding to D. mesomelas, D. mystacalis and four lineages within D. cfr. melanotis with high divergence values (ranges: 10.6% – 18.3%) that raises the question of the possible presence of cryptic species. The first description of the karyotype for D. mesomelas and D. mystacalis and C- and G- banding for one lineage of D. cfr. melanotis are reported highlighting an extended karyotype reorganization in the genus. Furthermore, the G-banding and Zoo-FISH evidenced an autosome-sex chromosome translocation characterizing all the species and our timing estimates this mutation date back 7.4 mya (Late Miocene). Finally, the molecular clock suggests that cladogenesis took place since the end of Miocene to Plio-Pleistocene, probably due to ecological factors, isolation in refugia followed by differential adaptation to the mesic or dry habitat

Chronic Myelomonocytic Leukemia - Single Entity Or Heterogeneous Disorder - a Prospective Multicenter Study of 100 Patients

To investigate the prognostic factors in chronic myelomonocytic leukemia (CMMoL), and to determine the importance of cytogenetic abnormalities at diagnosis and during evolution, a multicentric prospective study was established by the Groupe Francais de Cytogenetique Hematologique. One hundred patients were analyzed: 29 had cytogenetic abnormalities, among which the most frequent were +8, -Y, -7/7q-, and 12p-. Transformation into acute leukemia (AL) occurred in 26 patients. At transformation, eight patients had new cytogenetic abnormalities, not different from those described in the chronic phase of this disease. The median survival was 36 months (+/- 20 months, 95%, confidence interval). In multivariate analysis, four factors were associated with shorter survival: anemia < 10 g/dl, thrombocytopenia < 100 x 10(9)/L, splenomegaly, and the presence of immature precursors (IMP) in peripheral blood (PB). A very good prognosis subgroup could be identified which included eight patients with myelodysplasia and monocytosis only and none of the four unfavorable prognostic factors. This study confirmed the cytogenetic findings previously described by our group, and its results yielded further prognostic information. It also indicates the heterogeneity of this disease [some patients show clinical and biologic features of myeloproliferative syndromes (MDS, especially karyotypic abnormalities described only in these syndromes), whereas others appear more to have myelodysplasia, shifting from refractory anemia (RA) to CMMoL], and stresses the need for a more precise definition of this entity

Chronic Myelomonocytic Leukemia (cmml) - a Myelodysplastic Or Myeloproliferative Syndrome

Chronic myelomonocytic leukaemia (CMML), a disorder belonging to the group of myelodysplastic syndromes, has a number of peculiar features which raise the question as to whether it should be considered a distinct entity in its own right. The problems associated with its classification and diagnosis are discussed in this report using all currently available tools from clinical data to molecular genetics, including morphology, histology, cellular biology and cytogenetics. Three groups of patients can be identified (isolated monocytosis with a mild degree of dysplasia, severe cytopenia and the most frequent type with proliferative symptoms dominating the clinical picture). The latter group is close to atypical chronic myeloid leukaemia and perhaps these two entities should be regarded as a single one. Classification of the disease is further complicated by the possibility of evolution from one subgroup into another one and by the finding that CMML can also arise as a disorder secondary to other myeloproliferative (MPS) or myelodysplastic (MDS) syndromes. No specific marker of the disease has been identified by cytogenetics or molecular biology. Due to all these facts, we believe that CMML should perhaps be viewed more pragmatically by considering the use of prognostic factors that could at least help to define different groups of patients who may require different therapeutic strategies. We conclude that CMML is a heterogeneous syndrome with features of both MPS and MDS, encompassing primary and secondary stem cell disorders and varying widely in its clinical presentation. This heterogeneity should stimulate the search for reliable predictors of evolution which would allow a better definition of CMML subtypes based on prognostic factors