Spectroscopy of Ultracold LiRb Molecules Using Ionization Detection

We present spectroscopic studies of ultracold LiRb molecules using ionization detection. The molecules are created by cooling and trapping Li and Rb atoms in overlapping magneto-optical traps (MOTs) and using light resonant with a free-bound transition to create weakly bound excited state molecules in a process known as photoassociation (PA). We explore weakly bound vibrational levels of LiRb with PA spectroscopy using ionization detection and, where possible, compare our results with earlier measurements performed in our lab using trap-loss spectroscopy. In addition, we also probe vibrational levels of the ground triplet electronic state and excited electronic states using resonantly enhanced multiphoton ionization (REMPI) spectroscopy. We identify several vibrational levels of the α3Σ+, (3)3ΠΩ and (4)3Σ + states and compare our observations with theoretical calculations. As LiRb is one of the least studied heteronuclear diatomic molecules, these studies are aimed towards exploring the molecular structure. The spectroscopic work is also in line with the long-term project goals of transferring ultracold LiRb molecules into the lowest rotational and vibrational levels of the ground singlet electronic state. Molecules in this rovibronic ground state possess a large electric dipole moment, which is essential for application of ultracold molecules in various quantum computation schemes. The rovibronic ground state will also be an ideal starting point for investigating molecular entangled states

Research fatigue among injecting drug users in Karachi, Pakistan

Background Karachi is the largest metropolis of Pakistan and its economic hub attracting domestic migrants for economic opportunities. It is also the epicenter of HIV epidemic in the country. Since 2004, one pilot study and four behavioral and biological surveillance rounds have been conducted in Karachi. In addition many student research projects have also focused on key risk groups including injection drug users (IDUs). As a result of this extra ordinary exposure of same kind of questions, IDUs know how to respond to high value questions related to sharing of needles or unsafe sexual practices. The purpose of the study was to explore the element of research fatigue among IDUs in Karachi, Pakistan. Methods The study was conducted on 32 spots in Karachi, selected on the basis of estimate of IDUs at each spot. A trained field worker (recovered IDU) visited each spot; observed sharing behavior of IDUs and asked questions related to practices in January 2009. Verbal consent was obtained from each respondent before asking questions. Results On average 14 IDUs were present at each spot and out of 32 selected spots, 81% were active while more than two groups were present at 69% spots. In each group three to four IDUs were present and everyone in the group was sharing. One dose of injecting narcotics was observed. Sharing of syringes, needles and distilled water was observed at 63% spots while professional injector/street doctor was present at 60% spots. Conclusion There is a need to check internal consistency in surveillance research. It is highly likely that IDUs and other risk groups know how to respond to key questions but their responses do not match with the practices

Formation of deeply bound ultracold LiRb molecules via photoassociation near the Li 2S1/2_{1/2} + Rb 5P3/2_{3/2} asymptote

We present spectra of ultracold $^7$Li$^{85}$Rb molecules in their electronic ground state formed by spontaneous decay of weakly bound photoassociated molecules. Beginning with atoms in a dual species magneto-optical trap (MOT), weakly bound molecules are formed in the 4(1) electronic state, which corresponds to the B$^1\Pi$ state at short range. These molecules spontaneously decay to the electronic ground state and we use resonantly enhanced multiphoton ionization (REMPI) to determine the vibrational population distribution in the electronic ground states after spontaneous emission. Many of the observed lines from the spectra are consistent with transitions from the X$^1\Sigma^+$ ground electronic state to either the B$^1\Pi$ or D$^1\Pi$ electronic states that have been previously observed, with levels possibly as low as X$^1\Sigma^+$ $(v'' = 2)$ being populated. We do not observe decay to weakly bound vibrational levels of the X$^1\Sigma^+$ or a$^3\Sigma^+$ electronic states in the spectra. We also deduce a lower bound of 3900 cm$^{-1}$ for the dissociation energy of the LiRb$^+$ molecular ion.Comment: 6 pages, 4 figure

THE AGE DISTRIBUTION AND EFFECTIVENESS OF LOW DOSE TAMSULOSIN IN LOWER URETERIC STONES

Objective: To determine the effectiveness of low dose tamsulosin as a medical expulsive therapy in patients with lower ureteric stones. Patients and Methods: The six months randomized control trial was conducted on all patients with either gender, age range 30-60 years and stone size 4-10 mm in the lower 1/3rd of the ureter determined on ultrasound at tertiary care hospital. Group A patients was offered low dose tamsulosin (0.2 mg) one tablet daily in the morning for a maximum of 4 weeks and group B served as control. The final outcome was measured at the end of 4th week of treatment. Patients were instructed to note the time and the date of expulsion of stone. Absence of echoic shadows on lower 1/3rd of ureteric line on ultrasound was taken as effectiveness (expulsion of stone). Results: In control group mean age was 45.52 ±6.70 years whereas in low dose Tamsulin mean age was 46.72 ±6.73 years. Frequency of male was higher in both control and low dose Tamsulin group, i.e. 39 (78%) and 21 (42%) respectively. In control group effectiveness was found 3 (6%) patients whereas in low dose Tamsulin group effectiveness was found in 47 (94%). Conclusion: In our study the effectiveness of low dose tamsulosin as a medical expulsive therapy in patients with lower ureteric stones was higher as compared to control. Keywords: Low dose tamsulosin, Lower ureteric stones, Medical expulsive therap

The Arecibo Legacy Fast ALFA Survey: III. HI Source Catalog of the Northern Virgo Cluster Region

We present the first installment of HI sources extracted from the Arecibo Legacy Fast ALFA (ALFALFA) extragalactic survey, initiated in 2005. Sources have been extracted from 3-D spectral data cubes and then examined interactively to yield global HI parameters. A total of 730 HI detections are catalogued within the solid angle 11h44m < R.A.(J2000) < 14h00m and +12deg < Dec.(J2000) < +16deg, and redshift range -1600 \kms < cz < 18000 \kms. In comparison, the HI Parkes All-Sky Survey (HIPASS) detected 40 HI signals in the same region. Optical counterparts are assigned via examination of digital optical imaging databases. ALFALFA HI detections are reported for three distinct classes of signals: (a) detections, typically with S/N > 6.5; (b) high velocity clouds in the Milky Way or its periphery; and (c) signals of lower S/N (to ~ 4.5) which coincide spatially with an optical object of known similar redshift. Although this region of the sky has been heavily surveyed by previous targeted observations based on optical flux-- or size-- limited samples, 69% of the extracted sources are newly reported HI detections. The resultant positional accuracy of HI sources is 20" (median). The median redshift of the sample is ~7000 \kms and its distribution reflects the known local large scale structure including the Virgo cluster. Several extended HI features are found in the vicinity of the Virgo cluster. A small percentage (6%) of HI detections have no identifiable optical counterpart, more than half of which are high velocity clouds in the Milky Way vicinity; the remaining 17 objects do not appear connected to or associated with any known galaxy.Comment: Astronomical Journal, in pres