2,974 research outputs found
Quantum limited particle sensing in optical tweezers
Particle sensing in optical tweezers systems provides information on the
position, velocity and force of the specimen particles. The conventional
quadrant detection scheme is applied ubiquitously in optical tweezers
experiments to quantify these parameters. In this paper we show that quadrant
detection is non-optimal for particle sensing in optical tweezers and propose
an alternative optimal particle sensing scheme based on spatial homodyne
detection. A formalism for particle sensing in terms of transverse spatial
modes is developed and numerical simulations of the efficacy of both quadrant
and spatial homodyne detection are shown. We demonstrate that an order of
magnitude improvement in particle sensing sensitivity can be achieved using
spatial homodyne over quadrant detection.Comment: Submitted to Biophys
Decolorization of reactive red-120 by using macrofungus and microfungus
The objectives of the study are to investigate the growth of Aspergillus sp. and Pleurotus sp. and decolorization of Reactive Red – 120 in Minimal Salt Solution (MSS). The growths of fungi were measured every 3 days by using spectrophotometer at 540 nm. For decolorization, the fungi were cultured in 10 mg/L and 20 mg/L of dye concentration. Furthermore, pH of 5, 7 and 9 were used to determine the optimum pH for dye decolorization. The 10 mg/L concentration and pH 5 were chosen as optimum conditions with the maximum performance of reactive dye decolorization ranging of 60%-70%. The Aspergillus sp. was more efficient todecolourize synthetic dye Reactive Red – 120 when compared to Pleurotus sp. This study contributes to the knowledge of mycoremediation and product of mycoremediation kit that could be developed and applied in industry.Keywords: aspergillus sp.; dye decolorization; mycoremediation; pleurotus sp.; reactive red – 120; synthetic dye
Structural, optical, magnetic and electrical properties of Zn1-x Co (x) O thin films
Despite a considerable effort aiming at elucidating the nature of
ferromagnetism in ZnO-based magnetic semiconductor, its origin still remains
debatable. Although the observation of above room temperature ferromagnetism
has been reported frequently in the literature by magnetometry measurement, so
far there has been no report on correlated ferromagnetism in magnetic, optical
and electrical measurements. In this paper, we investigate systematically the
structural, optical, magnetic and electrical properties of Zn1-x Co (x) O:Al
thin films prepared by sputtering with x ranging from 0 to 0.33. We show that
correlated ferromagnetism is present only in samples with x > 0.25. In
contrast, samples with x < 0.2 exhibit weak ferromagnetism only in magnetometry
measurement which is absent in optical and electrical measurements. We
demonstrate, by systematic electrical transport studies that carrier
localization indeed occurs below 20-50 K for samples with x < 0.2; however,
this does not lead to the formation of ferromagnetic phase in these samples
with an electron concentration in the range of 6 x 10(19) cm(-3) 1 x 10(20)
cm(-3). Detailed structural and optical transmission spectroscopy analyses
revealed that the anomalous Hall effect observed in samples with x > 0.25 is
due to the formation of secondary phases and Co clusters.Comment: 28 pages, 8 figure
Cluster-randomized, crossover trial of head positioning in acute stroke
The role of supine positioning after acute stroke in improving cerebral blood flow and the countervailing risk of aspiration pneumonia have led to variation in head positioning in clinical practice. We wanted to determine whether outcomes in patients with acute ischemic stroke could be improved by positioning the patient to be lying flat (i.e., fully supine with the back horizontal and the face upwards) during treatment to increase cerebral perfusion. METHODS In a pragmatic, cluster-randomized, crossover trial conducted in nine countries, we assigned 11,093 patients with acute stroke (85% of the strokes were ischemic) to receive care in either a lying-flat position or a sitting-up position with the head elevated to at least 30 degrees, according to the randomization assignment of the hospital to which they were admitted; the designated position was initiated soon after hospital admission and was maintained for 24 hours. The primary outcome was degree of disability at 90 days, as assessed with the use of the modified Rankin scale (scores range from 0 to 6, with higher scores indicating greater disability and a score of 6 indicating death). RESULTS The median interval between the onset of stroke symptoms and the initiation of the assigned position was 14 hours (interquartile range, 5 to 35). Patients in the lying-flat group were less likely than patients in the sitting-up group to maintain the position for 24 hours (87% vs. 95%, P\u3c0.001). In a proportional-odds model, there was no significant shift in the distribution of 90-day disability outcomes on the global modified Rankin scale between patients in the lying-flat group and patients in the sitting-up group (unadjusted odds ratio for a difference in the distribution of scores on the modified Rankin scale in the lying-flat group, 1.01; 95% confidence interval, 0.92 to 1.10; P = 0.84). Mortality within 90 days was 7.3% among the patients in the lying-flat group and 7.4% among the patients in the sitting-up group (P = 0.83). There were no significant betweengroup differences in the rates of serious adverse events, including pneumonia. CONCLUSIONS Disability outcomes after acute stroke did not differ significantly between patients assigned to a lying-flat position for 24 hours and patients assigned to a sitting-up position with the head elevated to at least 30 degrees for 24 hours
The Role of Federated Learning in a Wireless World with Foundation Models
Foundation models (FMs) are general-purpose artificial intelligence (AI)
models that have recently enabled multiple brand-new generative AI
applications. The rapid advances in FMs serve as an important contextual
backdrop for the vision of next-generation wireless networks, where federated
learning (FL) is a key enabler of distributed network intelligence. Currently,
the exploration of the interplay between FMs and FL is still in its nascent
stage. Naturally, FMs are capable of boosting the performance of FL, and FL
could also leverage decentralized data and computing resources to assist in the
training of FMs. However, the exceptionally high requirements that FMs have for
computing resources, storage, and communication overhead would pose critical
challenges to FL-enabled wireless networks. In this article, we explore the
extent to which FMs are suitable for FL over wireless networks, including a
broad overview of research challenges and opportunities. In particular, we
discuss multiple new paradigms for realizing future intelligent networks that
integrate FMs and FL. We also consolidate several broad research directions
associated with these paradigms.Comment: 8 pages, 5 figures, 1 tabl
Selective interlayer ferromagnetic coupling between the Cu spins in YBa Cu O grown on top of La Ca MnO
Studies to date on ferromagnet/d-wave superconductor heterostructures focus
mainly on the effects at or near the interfaces while the response of bulk
properties to heterostructuring is overlooked. Here we use resonant soft x-ray
scattering spectroscopy to reveal a novel c-axis ferromagnetic coupling between
the in-plane Cu spins in YBa Cu O (YBCO) superconductor when it
is grown on top of ferromagnetic La Ca MnO (LCMO) manganite
layer. This coupling, present in both normal and superconducting states of
YBCO, is sensitive to the interfacial termination such that it is only observed
in bilayers with MnO_2but not with La Ca interfacial
termination. Such contrasting behaviors, we propose, are due to distinct
energetic of CuO chain and CuO plane at the La Ca and
MnO terminated interfaces respectively, therefore influencing the transfer
of spin-polarized electrons from manganite to cuprate differently. Our findings
suggest that the superconducting/ferromagnetic bilayers with proper interfacial
engineering can be good candidates for searching the theorized
Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) state in cuprates and studying the
competing quantum orders in highly correlated electron systems.Comment: Please note the change of the title. Text might be slightly different
from the published versio
Isostatic phase transition and instability in stiff granular materials
In this letter, structural rigidity concepts are used to understand the
origin of instabilities in granular aggregates. It is shown that: a) The
contact network of a noncohesive granular aggregate becomes exactly isostatic
in the limit of large stiffness-to-load ratio. b) Isostaticity is responsible
for the anomalously large susceptibility to perturbation of these systems, and
c) The load-stress response function of granular materials is critical
(power-law distributed) in the isostatic limit. Thus there is a phase
transition in the limit of intinitely large stiffness, and the resulting
isostatic phase is characterized by huge instability to perturbation.Comment: RevTeX, 4 pages w/eps figures [psfig]. To appear in Phys. Rev. Let
Endocrine profiles after triggering of final oocyte maturation with GnRH agonist after cotreatment with the GnRH antagonist ganirelix during ovarian hyperstimulation for in vitro fertilization
In a randomized multicenter study, the efficacies of two different GnRH
agonists were compared with that of hCG for triggering final stages of
oocyte maturation after ovarian hyperstimulation for in vitro
fertilization. Ovarian stimulation was conducted by recombinant FSH
(Puregon), and the GnRH antagonist ganirelix (Orgalutran) was
coadministered for the prevention of a premature LH rise. Luteal support
was provided by daily progestin administration. Frequent blood sampling
was performed at midcycle in the first 47 eligible subjects included in
the current study, who were randomized for a single dose of 0.2 mg
triptorelin (n = 17), 0.5 mg leuprorelin (n = 15), or 10,000 IU hCG (n =
15). Serum concentrations of LH, FSH, E2, and progesterone (P) were
assessed at variable intervals. LH peaked at 4 h after both triptorelin
and leuprorelin administration, with median LH levels of 130 and 107
IU/liter (P < 0.001), respectively. LH levels returned to baseline after
24 h. Subjects receiving hCG showed peak levels of 240 IU/liter hCG 24 h
after administration. A rise in FSH to 19 IU/liter (P < 0.001) was noted
in both GnRH agonist groups 8 h after injection. Within 24 h the areas
under the curve for LH and FSH were significantly higher (P < 0.001) in
both GnRH agonist groups compared with that for hCG. E2 and P levels were
similar for all groups up to the day of oocyte retrieval. Luteal phase
areas under the curve for P and E2 were significantly elevated (P < 0.001)
in the hCG group. The mean (+/-SD) numbers of oocytes retrieved were 9.8
+/- 5.4, 8.7 +/- 4.5, and 8.3 +/- 3.3; the percentages of metaphase II
oocytes were 72%, 85%, and 86%; and fertilization rates were 61%, 62%, and
56% in the triptorelin, leuprorelin, and hCG group, respectively (P = NS
for all three comparisons). These findings support the effective induction
of final oocyte maturation in both GnRH agonist groups. In summary, after
treatment with the GnRH antagonist ganirelix for the prevention of
premature LH surges, triggering of final stages of oocyte maturation can
be induced effectively by a single bolus injection of GnRH agonist, as
demonstrated by the induced endogenous LH and FSH surge and the quality
and fertilization rate of recovered oocytes. Moreover, corpus luteum
formation is induced by GnRH agonists with luteal phase steroid levels
closer to the physiological range compared with hCG. This more
physiological approach for inducing oocyte maturation may represent a
successful and safer alternative for in vitro fertilization patients
undergoing ovarian hyperstimulation
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