539 research outputs found
Comparison of mean temperature taken between commercial and prototype thermal sensor in estimating mean temperature of oil palm fresh fruit bunches
Thermal imaging is widely utilized in agricultural applications such as examining plant physiology, yield prediction, irrigation scheduling, bruises and pathogen determination in fruits and vegetables. There is a need for a cost effective thermal device for this wide range of applications. In this study, a low-cost prototype thermal device was used to measure the temperature of FFBs at three maturity levels, that are under-ripe, ripe and over-ripe. The experiment was repeated using a commercial thermal camera. Then, the mean temperature obtained from both the prototype and commercial thermal sensors was compared. Our results showed the prototype thermal device is capable of estimating the mean temperature of oil palm FFBs with the values analogous to the mean temperature from commercial thermal camera with R2 = 0.71
Complex Ashtekar variables and reality conditions for Holst's action
From the Holst action in terms of complex valued Ashtekar variables
additional reality conditions mimicking the linear simplicity constraints of
spin foam gravity are found. In quantum theory with the results of You and
Rovelli we are able to implement these constraints weakly, that is in the sense
of Gupta and Bleuler. The resulting kinematical Hilbert space matches the
original one of loop quantum gravity, that is for real valued Ashtekar
connection. Our result perfectly fit with recent developments of Rovelli and
Speziale concerning Lorentz covariance within spin-form gravity.Comment: 24 pages, 2 picture
CD4 Effectors Need to Recognize Antigen Locally to Become Cytotoxic CD4 and Follicular Helper T Cells [preprint]
T follicular helper (TFH) and Cytotoxic CD4 (ThCTL) are tissue-restricted CD4 effector subsets, functionally specialized to mediate optimal Ab production and cytotoxicity of infected cells. Influenza infection generates robust CD4 responses, including lung ThCTL and SLO TFH, that protect against reinfection by variant strains. Antigen (Ag) presentation after infection, lasts through the effector phase of the response. Here, we show that this effector phase Ag presentation, well after priming, is required to drive CD4 effectors to ThCTL and TFH. Using in vivo influenza models, we varied Ag presentation to effectors acutely, just at the effector phase. Ag presentation was required in the tissue of effector residence. We suggest these requirements contain unnecessary or potentially pathogenic CD4 responses, only allowing them if infection is uncleared. The results imply that providing effector phase Ag, would lead to stronger humoral and CD4 tissue immunity and thus can be applied to improve vaccine design
The twistorial structure of loop-gravity transition amplitudes
The spin foam formalism provides transition amplitudes for loop quantum
gravity. Important aspects of the dynamics are understood, but many open
questions are pressing on. In this paper we address some of them using a
twistorial description, which brings new light on both classical and quantum
aspects of the theory. At the classical level, we clarify the covariant
properties of the discrete geometries involved, and the role of the simplicity
constraints in leading to SU(2) Ashtekar-Barbero variables. We identify areas
and Lorentzian dihedral angles in twistor space, and show that they form a
canonical pair. The primary simplicity constraints are solved by simple
twistors, parametrized by SU(2) spinors and the dihedral angles. We construct
an SU(2) holonomy and prove it to correspond to the (lattice version of the)
Ashtekar-Barbero connection. We argue that the role of secondary constraints is
to provide a non trivial embedding of the cotangent bundle of SU(2) in the
space of simple twistors. At the quantum level, a Schroedinger representation
leads to a spinorial version of simple projected spin networks, where the
argument of the wave functions is a spinor instead of a group element. We
rewrite the Liouville measure on the cotangent bundle of SL(2,C) as an integral
in twistor space. Using these tools, we show that the
Engle-Pereira-Rovelli-Livine transition amplitudes can be derived from a path
integral in twistor space. We construct a curvature tensor, show that it
carries torsion off-shell, and that its Riemann part is of Petrov type D.
Finally, we make contact between the semiclassical asymptotic behaviour of the
model and our construction, clarifying the relation of the Regge geometries
with the original phase space.Comment: 40 pages, 3 figures. v2: minor improvements, references adde
Rabies Situation in Cambodia
In Cambodia, rabies still elicits fear in the communities. Since 1998 the Institut Pasteur in Cambodia (IPC), Phnom Penh has been the only source of free post-exposure prophylaxis (PEP) and post mortem diagnosis. During 1998–2007, on average ∼12,400 patients received PEP annually at IPC (range 8,907–14,475) and 63 fatal human cases presenting with encephalitis following a dog bite were reported including 73% who tested positive by fluorescent-antibody test on brain samples or/and by reverse-transcriptase polymerase chain reaction on skin, cerebrospinal fluid, or urine. In 2007, 14,475 patients received PEP (100 PEP/100,000 people in Cambodia) including 95% who resided in Phnom Penh city (615 PEP/100,000) or five neighboring provinces. Using a step-by-step probability model, we estimated that 810 human rabies deaths would occur in 2007 (95% confidence interval [CI] 394–1,607); an incidence of 5.8/100,000 (95%CI 2.8–11.5). As a result, despite high attendance at the IPC's PEP center most Cambodians living in peripheral provinces in Cambodia may not have adequate access to PEP. Finally, the model generated one of the highest incidences of rabies worldwide. A national rabies control program is needed to improve surveillance and access to PEP, and to initiate vaccination campaigns in dogs
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A Novel Excitatory Paraventricular Nucleus to AgRP Neuron Circuit that Drives Hunger
Summary Hunger is a hard-wired motivational state essential for survival. Agouti-related peptide (AgRP)-expressing neurons in the arcuate nucleus (ARC) at the base of the hypothalamus are crucial to its control. They are activated by caloric deficiency and, when naturally or artificially stimulated, they potently induce intense hunger and subsequent food intake1-5. Consistent with their obligatory role in regulating appetite, genetic ablation or pharmacogenetic inhibition of AgRP neurons decreases feeding3,6,7. Excitatory input to AgRP neurons is key in caloric-deficiency-induced activation, and is notable for its remarkable degree of caloric state-dependent synaptic plasticity8-10. Despite the important role of excitatory input, its source(s) has been unknown. Here, through the use of Cre-recombinase-enabled, cell-specific neuron mapping techniques, we have discovered strong excitatory drive that, unexpectedly, emanates from the hypothalamic paraventricular nucleus, specifically from subsets of neurons expressing Thyrotropin-releasing hormone (TRH) and Pituitary adenylate cyclase-activating polypeptide (PACAP). Pharmaco-genetic stimulation of these afferent neurons in sated mice markedly activates AgRP neurons and induces intense feeding. Conversely, acute inhibition in mice with caloric deficiency-induced hunger decreases feeding. Discovery of these afferent neurons capable of triggering hunger advances understanding of how this intense motivational state is regulated
Up-Regulation of Annexin-A1 and Lipoxin A4 in Individuals with Ulcerative Colitis May Promote Mucosal Homeostasis
PubMed ID: 22723974This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
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