35 research outputs found
Wakes in a Collisional Quark-Gluon Plasma
Wakes created by a parton moving through a static and infinitely extended
quark-gluon plasma are considered. In contrast to former investigations
collisions within the quark-gluon plasma are taken into account using a
transport theoretical approach (Boltzmann equation) with a
Bhatnagar-Gross-Krook collision term. Within this model it is shown that the
wake structure changes significantly compared to the collisionless case.Comment: 16 pages, 4 figures, high resolution figures available from the
authors, final version to be published in J. Phys.
Study of association of dry eye with diabetes mellitus
Background: Aim of the study was to evaluate the tear status in diabetes mellitus (DM) patient.
Methods: This study was a prospective observational case control study. Eighty patients with DM aged from 50 to 80 years were compared with a group of 80 normal healthy age matched control group. A general ophthalmological check-up was performed. The main points of comparison were subjective complaints, objective findings on basic Schirmer test, break-up time, Rose Bengal test.
Results: The results show that 27.5% of all diabetic subjects accompanied of dry eye symptoms, as against 6.25% of the control group. A mean BUT value was 15.5s and Standard Error was 0.20. In the control group mean BUT value was 14s and standard error was 0.23. Basic Schirmer test in DM group mean value was 9.50 mm and SE was 0.268. In the control group mean basic Schirmer test value was 15 mm and SE was 0.405. Rose Bengal test score in DM group, normal score (score <3) was found in 80% case and abnormal score (score >3) was found in 20%. In the control group, normal score was found in 93.75% and abnormal score was found in 6.25% case. Dry eye percentage in DM group 11.25% had definitive dry eye, 16.25% cases had possible dry eye and 72.5% cases had no dry eye. In control group 2.50% cases had definitive dry eye, 3.75% cases had possible dry eye and 93.75% had no dry eye.
Conclusions: The study shows that dry eye is associated with DM
Modified almost unbiased two-parameter estimator for the Poisson regression model with an application to accident data
Due to the large amount of accidents negatively affecting the wellbeing of the survivors and their families, a substantial amount of research is conducted to determine the causes of road accidents. This type of data come in the form of non-negative integers and may be modelled using the Poisson regression model. Unfortunately, the commonly used maximum likelihood estimator is unstable when the explanatory variables of the Poisson regression model are highly correlated. Therefore, this paper proposes a new almost unbiased estimator which reduces the instability of the maximum likelihood estimator and at the same time produce smaller mean squared error. We study the statistical properties of the proposed estimator and a simulation study has been conducted to compare the performance of the estimators in the smaller mean squared error sense. Finally, Swedish traffic fatality data are analyzed to show the benefit of the proposed method
On the Liu and almost unbiased Liu estimators in the presence of multicollinearity with heteroscedastic or correlated errors
This paper introduces a new biased estimator, namely, almost unbiased Liu estimator (AULE) of β for the multiple linear regression model with heteroscedastics and/or correlated errors and suffers from the problem of multicollinearity. The properties of the proposed estimator is discussed and the performance over the generalized least squares (GLS) estimator, ordinary ridge regression (ORR) estimator (Trenkler, 1984), and Liu estimator (LE) (Kaçiranlnar, 2003) in terms of matrix mean square error criterion are investigated. The optimal values of d for Liu and almost unbiased Liu estimators have been obtained. Finally, a simulation study has been conducted which indicated that under certain conditions on d, the proposed estimator performed well compared to GLS, ORR and LE estimators
The extent of strangeness in equilibration in quark-gluon plasma
The evolution and production of strangeness from chemically equilibrating and
transversely expanding quark gluon plasma which may be formed in the wake of
relativistic heavy ion collisions is studied with initial conditions obtained
from the Self Screened Parton Cascade (SSPC) model. The extent of partonic
equilibration increases almost linearly with the square of the initial energy
density, which can then be scaled with number of participants.Comment: 4 pages including three figures, talk given at ICPAQGP'01, Jaipur,
India, to appear in Pramana - Journal of Physics, Indian Academy of Scienc
Body Indices and Population Dynamics of Setipinna breviceps (Cantor, 1849) from Batang Lassa Estuary, Sarawak, Malaysia
The Setipinna breviceps is a commercially important and highly esteemed food fish. This species has scant of scientific formation particularly on population parameters like growth, mortality and recruitment. The present study aimed to estimate the body indices and population parameters of Setipinna breviceps of Batang Lassa Estuary (BLE). Samples were collected between April 2019 and September 2020. A local made bag net known as Gnian (mesh size 1.25 to
4.00 cm) was used for sampling the fish. A total of 287 qualified specimens were used for this study. The length and
weight of individual fish was measured to the nearest 0.1 cm and 0.01 g, respectively. The length ranged from 5.50 to
24.00 cm and growth coefficient (b) was 2.563 (R
2 = 0.87) which clearly indicated a negative allometric growth. About 50% of individuals showed flat or slender body (Kn1) while 2.44% of fishes measured an ideal shape (Kn = 1). The parameters of growth L∞, K and ϕ’ were estimated at 24.15
cm, 0.23 yr-2 and 2.13, respectively. The estimated natural mortality and fishing mortality were 0.74 and 0.29 yr-2
, respectively and exploitation rate was 0.28. The recruitment pattern during the study was observed at two possible unequal peaks. The present study concluded that the anchovy was under exploited (E<0.5) as demonstrated by the
under-sized fishes caught with small mesh size net. However, considering the minimum lengths and length at first
catch, the BLE could be a productive nursery ground for S. breviceps. Therefore, management actions are required to
avoid juvenile catches
Biometric indices and population parameters of three polynemid fishes from Batang Lassa Estuary of East Malaysia
The length-weight relationships (LWRs), condition factor (Kn), growth, mortality
and exploitation status of three polynemid fishes, i.e., Filimanus xanthonema
(Valenciennes, 1831), Polynemus melanochir (Valenciennes, 1831) and Polynemus
paradiseus (Linnaeus, 1758) from Batang Lassa River estuary were estimated. Fish
samples were caught during April 2019 to September 2020 using the ESBN (locally
called Gnian) having 1.25 to 4.00 cm mesh size. The total length (TL) and body
weight of each individual fish was measured to the nearest 0.1 cm and 0.01 g
respectively. The growth coefficients (b) for F. xanthonema, P. melanochir and
P. paradiseus, were 2.880, 2.717 and 2.724 with the R2 values 0.956, 0.972 and 0.936
respectively. Estimated growth coefficients indicated a negative allometric growth
pattern for all three threadfin fishes. To date, information regarding length-weight
relationships for F. xanthonema and P. melanochir is insufficient whereas the
information is available for P. paradiseus. About 40–48% of fishes exhibited flat or
thin body shape (Kn 1) and only 1–3%
of fishes showed proportional body shape (Kn = 1). The growth parameters L∞, K
and ϕ’ were estimated at 15.75 cm, 0.95 yr−1 and 2.37 for F. xanthonema;
27.61 cm 0.87 yr−1 and 2.82 for P. melanochir; and 27.30 cm, 0.58 yr−1 and 2.64 for
P. paradiseus; respectively. The estimated natural mortality (M) included 2.10, 1.69
and 1.30 yr−1
; the fishing mortality (F) 0.57, 0.67 and 0.60 yr−1
; and exploitation
ratio (E) 0.21, 0.28 and 0.31 for F. xanthonema, P. melanochir and P. paradiseus
respectively. The study concluded that the stocks are still under exploitation (E < 0.5)
condition. However, the studied Batang Lassa estuary could be a potential nursery
ground considering the minimum lengths of 5.0, 3.8 and 4.0 cm for F. xanthonema,
P. melanochir and P. paradiseus respectively. Therefore, management initiatives are
needed to escape juvenile catches
A Force Sensor that Converts Fluorescence Signal into Force Measurement Utilizing Short Looped DNA
A force sensor concept is presented where fluorescence signal is converted into force information via single-molecule Förster resonance energy transfer (smFRET). The basic design of the sensor is a ~100 base pair (bp) long double stranded DNA (dsDNA) that is restricted to a looped conformation by a nucleic acid secondary structure (NAS) that bridges its ends. The looped dsDNA generates a tension across the NAS and unfolds it when the tension is high enough. The FRET efficiency between donor and acceptor (D&A) fluorophores placed across the NAS reports on its folding state. Three dsDNA constructs with different lengths were bridged by a DNA hairpin and KCl was titrated to change the applied force. After these proof-of-principle measurements, one of the dsDNA constructs was used to maintain the G-quadruplex (GQ) construct formed by thrombin binding aptamer (TBA) under tension while it interacted with a destabilizing protein and stabilizing small molecule. The force required to unfold TBA-GQ was independently investigated with high-resolution optical tweezers (OT) measurements that established the relevant force to be a few pN, which is consistent with the force generated by the looped dsDNA. The proposed method is particularly promising as it enables studying NAS, protein, and small molecule interactions using a highly-parallel FRET-based assay while the NAS is kept under an approximately constant force
Evolution of strangeness in equilibrating and expanding quark-gluon plasma
We evaluate the strangeness production from equilibrating and transversely
expanding quark gluon plasma which may be created in the wake of relativistic
heavy ion collisions. We consider boost invariant longitudinal and
cylindrically symmetric transverse expansion of a gluon dominated partonic
plasma, which is in local thermal equilibrium. Initial conditions obtained from
the self screened parton cascade model are used. We empirically find that the
final extent of the partonic equilibration rises almost linearly with the
square of the initial energy density. This along with the corresponding
variation with the number of participants may help us distinguish between
various models of parton production.Comment: RevTex, 10 pages including 6 figures comprising 11 postscript files,
text modified considerably with an added figure (Fig. 6) and this version
accepted for publication in Phys. Rev.
Soft Electromagnetic Radiations From Equilibrating Quark-Gluon Plasma
We evaluate the bremsstrahlung production of low mass dileptons and soft
photons from equilibrating and transversely expanding quark gluon plasma which
may be created in the wake of relativistic heavy ion collisions. We use initial
conditions obtained from the self screened parton cascade model. We consider a
boost invariant longitudinal and cylindrically symmetric transverse expansion
of the parton plasma and find that for low mass dileptons ( GeV)
and soft photons ( GeV), the bremsstrahlung contribution is
rather large compared to annihilation process at both RHIC and LHC energies. We
also find an increase by a factor of 15-20 in the low mass dileptons and soft
photons yield as one goes from RHIC to LHC energies.Comment: 8 pages, including 7 figures To appear in Phys. Rev.