Tata Institute of Fundamental Research

About: Tata Institute of Fundamental Research is a education organization based out in Mumbai, Maharashtra, India. It is known for research contribution in the topics: Magnetization & Large Hadron Collider. The organization has 7786 authors who have published 21742 publications receiving 622368 citations. The organization is also known as: TIFR.

Sensilla on the tarsal segments and mouthparts of adult Drosophila melanogaster meigen (Diptera : Drosophilidae)

Abstract: Sensilla on the tarsal segments of legs and on the external and internal mouthparts of adult Drosophila melanogaster Meigen (Diptera : Drosophilidae) were studied by light and electron microscopy. Tarsi are invested with bracteate and bractless bristles. Ethanolic silver nitrate stain distinguishes dendrite-containing bristles from other hairs on the tarsi. Stained bristles are bractless. Males have more silver-staining bristles than females on the I st 4 tarsal segments of prothoracic legs. There are 33 – 34 taste bristles on each half of the labellum. Many of them are 2-pronged. Both prongs have a pore at the tip, but chemosensory dendrites enter only in one of them. The taste bristles in the 2 medial rows on each half of the labellum are predominantly associated with 4 chemosensory neurons and the peripheral bristles usually contain 2 chemosensory neurons each. Five groups of paired sense organs are known to exist on the internal mouthparts. Amongst 9 sensilla present in the labral sense organ, electron microscopy shows that sensilla numbers 1 – 6 have one mechanosensory neuron each. Sensillum number 7 has 8 neurons with dendrites arranged in 3 groups: 2 triplets and a pair. Sensilla 8 and 9 have 2 neurons each. The ventral cibarial sense organ (VCSO) has 2 sensilla, one with 2 and the other with 4 neurons. Rows of hollow satellite bristles forming 2 sensory systems, dorsal and ventral to the VCSO have one mechanosensory neuron each. The dorsal cibarial sense organ has 2 sensilla on either side of the midline, each containing 3 neurons. The paper describes the fine structural morphology of taste receptors and enumerates axons of all the prominent nerves of mouthparts at different levels. An external nerve loop connecting directly 2 regions of the brain, the tritocerebrum and suboesophageal ganglion, is reported.

Measurement of the forward-backward charge asymmetry in top-quark pair production

Abstract: We present the first measurement of the integrated forward-backward charge asymmetry in top-quark-top-antiquark pair (t (t) over bar) production in proton-antiproton (p (p) over bar) collisions in the lepton+jets final state. Using a b-jet tagging algorithm and kinematic reconstruction assuming t (t) over bar +X production and decay, a sample of 0.9 fb(-1) of data, collected by the D0 experiment at the Fermilab Tevatron Collider, is used to measure the asymmetry for different jet multiplicities. The result is also used to set upper limits on t (t) over bar +X production via a Z' resonance.

Charged particle multiplicities in pp interactions at sqrt(s) = 0.9, 2.36, and 7 TeV

Abstract: Measurements of primary charged hadron multiplicity distributions are presented for non-single-diffractive events in proton-proton collisions at centre-of-mass energies of sqrt(s) = 0.9, 2.36, and 7 TeV, in five pseudorapidity ranges from |eta|<0.5 to |eta|<2.4. The data were collected with the minimum-bias trigger of the CMS experiment during the LHC commissioning runs in 2009 and the 7 TeV run in 2010. The multiplicity distribution at sqrt(s) = 0.9 TeV is in agreement with previous measurements. At higher energies the increase of the mean multiplicity with sqrt(s) is underestimated by most event generators. The average transverse momentum as a function of the multiplicity is also presented. The measurement of higher-order moments of the multiplicity distribution confirms the violation of Koba-Nielsen-Olesen scaling that has been observed at lower energies.

Herschel/HIFI observations of interstellar OH+ and H2O+ towards W49N: a probe of diffuse clouds with a small molecular fraction

Abstract: We report the detection of absorption by interstellar hydroxyl cations and water cations, along the sight-line to the bright continuum source W49N. We have used Herschel's HIFI instrument, in dual beam switch mode, to observe the 972 GHz N = 1-0 transition of OH+ and the 1115 GHz 1(11)-0(00) transition of ortho-H2O+. The resultant spectra show absorption by ortho-H2O+, and strong absorption by OH+, in foreground material at velocities in the range 0 to 70 km s(-1) with respect to the local standard of rest. The inferred OH+/H2O+ abundance ratio ranges from similar to 3 to similar to 15, implying that the observed OH+ arises in clouds of small molecular fraction, in the 2-8% range. This conclusion is confirmed by the distribution of OH+ and H2O+ in Doppler velocity space, which is similar to that of atomic hydrogen, as observed by means of 21 cm absorption measurements, and dissimilar from that typical of other molecular tracers. The observed OH+/H abundance ratio of a few x10(-8) suggests a cosmic ray ionization rate for atomic hydrogen of 0.6-2.4 x 10(-16) s(-1), in good agreement with estimates inferred previously for diffuse clouds in the Galactic disk from observations of interstellar H-3(+) and other species.