Results: EORA patients were associated with high HAQDI (>= 1) in bivariable analysis [odds ratio (OR) 1.36, confidence interval (CI) 1.04-1.77]. However, in multivariable analysis, not elderly onset but patients’ age, female gender, high disease activity, disease duration over 10 years, and comorbidity find protocol with cardiovascular disease were associated with high HAQDI. Only in a predefined subgroup with disease duration <10 years, elderly onset was an independent influencing factor

for the functional disability of RA patients (OR 3.04, CI 1.85-5.67: disease duration of <5 years, OR 3.07, CI 1.64-5.74: disease duration of 5 to 10 years).

Conclusions: Disease onset in older age was associated independently with functional disability of RA patients who have relatively short disease duration. (C) 2012 Elsevier Inc. All rights reserved. Semin Arthritis Rheum 42:23-31″
“Background: Severe peritoneal injury and encapsulating peritoneal sclerosis (EPS) as complications of long-term peritoneal dialysis (PD) are issues of concern. The usefulness of peritoneal lavage after withdrawal of PD and the risk factors for EPS have not been addressed until now. Little is known about mesothelial cell area (MCA) in the effluent as a marker of peritoneal injury. In the present study, we investigated the clinical significance of peritoneal lavage after PD withdrawal and tried to clarify the risk factors

related to MCA, with the aim of preventing EPS. We also developed an algorithm for the clinical management of long-term PD patients.

Methods: Prexasertib molecular weight We assigned 247 PD patients to one of two cohorts after PD withdrawal: a non-lavage group (73 patients) and a lavage group (174 patients). To clarify the Evofosfamide Others inhibitor risk factors, we studied these potential predictors: PD duration, dialysate-to-plasma ratio of creatinine (D/P Cr)

at the time of PD withdrawal, frequency of peritoneal lavage, type of PD or lavage solution, MCA at the time of PD withdrawal (“”PD area”"), and MCA at the time of peritoneal lavage withdrawal or censoring (“”LA area”"). Recurrent intestinal obstruction was defined as the main manifestation of EPS. Diagnostic performance and cut-off values were then calculated for the selected risk factors.

Results: The overall incidence of EPS was significantly lower in the lavage group, at 6.9% (5.2% during lavage and 2.5% after lavage), than in the non-lavage group, at 15.1%. The risk factors and cut-off values were PD area (350 mu m(2)) and PD duration (78 months) for the non-lavage group; and PD area (350 mu m(2)) and LA area (320 mu m(2)) for the lavage group. Patients with a PD duration of 78 months or more and a PD area of 350 mu m(2) or more were defined as high-risk patients in the non-lavage group (risk ratio: 11.14), and patients with a PD area of 350 mu m(2) or more and an LA area of 320 mu m(2) or more were defined as high-risk patients in the lavage group (risk ratio: 10.43).

3%, P 0.62 and 10.9%, 0.12, respectively). However, age did significantly adversely decrease obturator internus muscle maximum CSA and

volume (24.5% and 28.2%, P < 0.001, respectively). Significant local age-related changes were observed dorsally in both muscles. Conclusions: Unlike the adjacent appendicular muscle, obturator internus, the levator ani muscle in healthy nullipara does not show evidence of significant age-related atrophy. Neurourol. Urodynam. 31: 481-486, 2012. (C) 2012 Wiley Periodicals, Inc.”
“Background: To investigate the value of diffusion-weighted imaging (DWI) at 3.0 T (3T), and especially the apparent diffusion coefficient (ADC), in discriminating PD0325901 inhibitor ovarian thecoma from other adnexal solid masses.

Methods: Eighteen thecomas or fibrothecomas, 14 ligamentous leiomyomas, and 24 other ovarian solid tumors underwent prospective DWI magnetic resonance imaging

(MRI) in addition to routine MRI on a 3T MRI machine. The baseline characteristics, components, and conventional MRI and DWI-MRI signals for the thecomas were recorded. The ADC values (ADCs) were measured for each group and compared.

Results: The thecomas often appeared as homogeneous isointensity (17/18) on T1-weighted images (T1WI; 11/18) or T2WI (11/18) on DWI-MRI, with minor (9/18) or mild (6/18) enhancement. The mean ADC value for thecoma (1.20 +/- 0.45 x 10(-3) mm(2)/s) was almost equal to that of the other solid ovarian masses (1.26 +/- 0.51 x selleck products 10(-3) mm(2)/s), but lower than that for leiomyoma (1.48 +/- 0.42 x 10(-3) mm(2)/s), although not significantly so. There was a significant difference (p = 0.043) in the ADCs of the benign ovarian solid masses (1.16 +/- 0.47 x 10(-3) mm(2)/s) and leiomyomas (1.48 +/- 0.42 x 10(-3) mm(2)/s).

Conclusions: There is no significant difference in ADC between thecoma and other adnexal solid masses, but the

ADCs of thecomas are lower than those of leiomyomas.”
“Active default tracing is an integral part of tuberculosis (TB) programmatic see more control. It can be differentiated into the tracing of defaulters (patients not seen at the clinic for >= 2 months) and ‘late patients’ (late for their scheduled appointments). Tracing is carried out to obtain reliable information about who has truly died, transferred out or stopped treatment, and, if possible, to persuade those who have stopped treatment to resume. This is important because, unlike routine care for non-communicable diseases, TB has the potential for transmission to other members of the community, and therefore presents the issue of the rights of the individual over the rights of the community. For this reason, default or ‘late patient’ tracing (defined together as default tracing in this article) has been incorporated into standard practice in most TB programmes and, in many industrialised countries, it is also a part of public health legislation.

Results: From April 1, 2004 through December 31, 2007, 12,062 children presented in clinic with eligible Cilengitide febrile and respiratory illnesses, from whom 321 influenza isolates were obtained from 2370 nasopharyngeal washes (13.5%), representing 16,043 child-years of observation (adjusted influenza incidence 102 episodes/1000 child-years). There were 8198 pneumonia episodes during the period (pneumonia incidence 511 episodes/1000 child-years). Ninety influenza-positive children (28%) developed pneumonia during their illness. Among influenza culture-positive children, those

with pneumonia were younger than those without (23.4 vs. 29.7 months, ANOVA: P < 0.001). Pneumonia was more commonly associated with Influenza A (H3N2) than either A (H1N1) or B infections (age-adjusted relative odds (RO) 2.98, [95% CI: 1.56, 5.71] and 2.75, [95% CI: 1.52, 4.98], respectively). Influenza was associated with 10% all childhood pneumonia.

Conclusions: Influenza is a major contributor to childhood pneumonia both through high influenza infection VX-770 molecular weight incidence and high pneumonia prevalence among infected children. Its contribution to early childhood pneumonia appears under-appreciated

in high pneumonia-endemic tropical settings. Influenza vaccine trials against childhood pneumonia are warranted.”
“BACKGROUND: Dyslipidemia results from consumption of a diet rich in saturated fatty acids and is usually associated with cardiovascular disease. A diet rich in unsaturated fatty acids is usually associated with improved cardiovascular condition.

OBJECTIVE: To investigate whether a high-fat diet rich in unsaturated fatty acids (U-HFD)-in which fatty

acid represents approximately 45% of the total calories-impairs the cardiovascular system.

METHODS: Male, 30-day-old Wistar rats were fed a standard (control) diet or a U-HFD containing 83% unsaturated fatty acid for 19 weeks. The in vivo electrocardiogram, the spectral analysis of heart EPZ5676 rate variability, and the vascular reactivity responses to phenylephrine, acetylcholine, noradrenaline and prazosin in aortic ring preparations were analyzed to assess the cardiovascular parameters.

RESULTS: After 19 weeks, the U-HFD rats had increased total body fat, baseline glucose levels and feed efficiency compared with control rats. However, the final body weight, systolic blood pressure, area under the curve for glucose, calorie intake and heart weight/final body weight ratio were similar between the groups. In addition, both groups demonstrated no alteration in the electrocardiogram or cardiac sympathetic parameters. There was no difference in the responses to acetylcholine or the maximal contractile response of the thoracic aorta to phenylephrine between groups, but the concentration necessary to produce 50% of maximal response showed a decrease in the sensitivity to phenylephrine in U-HFD rats.

We find a non-neutral regime where, for any given population size, there is an optimal mutation selleck kinase inhibitor bias that maximizes fitness. Interestingly, this optimal GC usage is small for small populations, large for intermediate populations and around 50% for large populations. This result is robust with respect to the definition of the fitness function and to the protein structures studied. Our model suggests that small populations evolving with small GC usage eventually accumulate a significant selective advantage over populations evolving without this bias.

This provides a possible explanation to the observation that most species adopting obligatory intracellular lifestyles with a consequent reduction of effective population size shifted their mutation spectrum towards AT. The model also predicts that large GC usage is optimal for intermediate population size. To test these predictions we estimated the selleck inhibitor effective population sizes of bacterial species using the optimal codon usage coefficients

computed by dos Reis et al. and the synonymous to non-synonymous substitution ratio computed by Daubin and Moran. We found that the population sizes estimated in these ways are significantly smaller for species with small and large GC usage compared to species with no bias, which supports our prediction.”
“Background: The pathogenicity of Plasmodium falciparum is in part due to the ability of the parasitized red blood cell (pRBC) to adhere to intra- vascular host cell receptors and serum-proteins. Binding of the pRBC is mediated by Plasmodium buy AZD6738 falciparum erythrocyte membrane protein 1 (PfEMP1), a large multi-variant molecule encoded by a

family of approximate to 60 var genes.

Methods: The study of var gene transcription in the parasite clone FCR3S1.2 was performed by semi-quantitative PCR and quantitative PCR (qPCR). The expression of the major PfEMP1 in FCR3S1.2 pRBC was analysed with polyclonal sera in rosette disruption assays and immunofluorecence.

Results: Transcripts from var1 (FCR3S1.2(var1); IT4var21) and other var genes were detected by semi-quantitative PCR but results from qPCR showed that one var gene transcript dominated over the others (FCR3S1.2var2; IT4var60). Antibodies raised in rats to the recombinant NTS-DBL1a of var2 produced in E. coli completely and dosedependently disrupted rosettes (approximate to 95% at a dilution of 1/5). The sera reacted with the Maurer’s clefts in trophozoite stages (IFA) and to the infected erythrocyte surface (FACS) indicating that FCR3S1.2var2 encodes the dominant PfEMP1 expressed in this parasite.

Conclusion: The major transcript in the rosetting model parasite FCR3S1.2 is FCR3S1.2var2 (IT4var60). The results suggest that this gene encodes the PfEMP1-species responsible for the rosetting phenotype of this parasite. The activity of previously raised antibodies to the NTS-DBL1a of FCR3S1.

Yields of biosurfactants, emulsion indices and surface tension were considerably higher in culture liquor and preparations derived from cultures grown anaerobically at a C/N ratio of 1: 24, pH 7.0, and temperature of 30A degrees C. Biosurfactant production by B. lichenformis also depended on concentrations of NaCl and Na(2)S in the medium and on water characteristics, reaching 4.58 g/l for bacteria grown anaerobically on a medium containing anolyte fraction of water.”
“The Oligomycin A mw reaction of trisubstituted o-benzoquinones with substituted anilines gives unstable o-benzoquinone imines which undergo intramolecular cyclization

to 4aH-phenoxazine derivatives. Dimerization of the latter according to Diels-Alder yields complex heterocyclic

systems, 7a,14a,15a,15b-tetrahydro-14,16-dioxa-5,9-diaza-8,15-ethenohexaphenes. Effective shielding of the carbonyl groups in 3,6-di-tert-butyl-4-isopropyl-o-benzoquinone makes it inactive toward substituted anilines.”
“Objectives

Hyperbaric oxygen therapy (HBOT) is used clinically in irradiation-induced injury to healthy tissues, but the effectiveness and working mechanism remain unclear. This study examined the effects of HBOT on irradiated salivary glands and tongue in a mouse www.selleckchem.com/products/rg-7112.html model.

Materials and Methods

Mice were irradiated with a single dose (15Gy) in the head and neck region and subjected to HBOT, either before or after irradiation. During the course of the treatments,

salivary flow rates were measured and at different time points after radiation (2, 6, 10 and 24weeks), salivary glands and tongue were harvested and (immuno) histochemically analysed.

Results

Proliferation and blood vessel density in salivary glands were enhanced by HBOT in the medium term (10weeks after irradiation), while salivary flow rates were not influenced. In the long term, irradiation-induced proliferation in the muscle tissue of the tongue was P005091 order decreased by HBOT.

Conclusion

Hyperbaric oxygen therapy (HBOT) appears to stimulate regeneration or protection of salivary gland tissue following radiation therapy. Possible implications of the effect of HBOT on muscle tissue of the tongue for the prevention of dysphagia and trismus are discussed. This study provides insights on the cellular changes after HBOT and encourages further research on this topic to achieve a better implementation of the therapy in humans.”
“Objective: To assess a wide spectrum of biochemical markers (biomarkers) in a large cohort of individuals with (very) early symptomatic knee and/or hip osteoarthritis (OA). Secondly, to investigate associations between biomarkers and between biomarkers and demographics to demonstrate validity of the obtained dataset and further investigate the involvement and/or role of these biomarkers in OA.

“
“Objective: To evaluate the prognostic impact of early recurrence (within 12 months) after surgery on cancer-specific survival (CSS) of patients with localized clear-cell renal cell carcinoma (ccRCC). Methods: Patients with surgically treated localized ccRCC were studied. Using the Kaplan-Meier method, we calculated CSS; by univariate and multivariate models we analyzed the association of early recurrence with cancer-related mortality. Results: We identified 259 patients with pT1-4/NX/0M0 ccRCC treated between February 1981 and September 2009; of 66 (25.5%)

with disease recurrence, 29 (43.9%) had buy NCT-501 early relapse. Overall, 43 patients (16.6%) died from ccRCC. The 5- and 10-year CSS for those without, late and early recurrence was 98.5 and 96.5%, 53 and 39.8%, and 23 and 23%, respectively (p < 0.0001). In the multivariate Cox model, pT stage (p = 0.01) and early recurrence (p < 0.0001) independently predicted CSS. Conclusions: Recurrent disease after localized ccRCC confers a poor prognosis, especially if detected within 12 months after surgery. Thus, this criterion should be included as an independent risk factor find more for cancer-related mortality. Copyright (C) 2010

S. Karger AG, Basel”
“The magnetofluctuation conductivity, called excess conductivity, originated from the forming of the superconducting droplet near to the mean-field transition temperature, was measured for the optimally doped BaFe1.8Co0.2As2 single crystals with a critical temperature, T-c, of 24.6 K. This measurement of the excess conductivity for magnetic fields up to 9 T was compared with the thermodynamic scaling theory in the critical region, in which not only the Gaussian fluctuation but also fourth order terms of the order buy LY411575 parameter are included. An analysis of the excess conductivity showed that the superconductivity followed

three-dimensional scaling rather than two-dimensional scaling even though the sample had a layered structure. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3478716]“
“Background: Sunitinib is standard first-line therapy for metastatic clear cell renal cancer (MCRC). It is associated with leucopenia; however, its effects on specific immune cell subsets are unclear. Alterations in immune cell subsets may contribute to tumour progression. Methods: Lymphocyte subsets (CD3, 4, 8, 19 and 56) were measured in 43 untreated MCRC patients who received sunitinib. The protocol included a structured treatment interruption of 5 weeks. Cell populations were measured at specific time points during sunitinib treatment and the treatment break. Results: Sunitinib was associated with significant declines in total leucocyte (-48%), neutrophil (-62%), CD3 total T cell (-31%) and CD4 counts (32%; p < 0.05). There was no significant change in CD19 B lymphocyte, CD8 or CD56 natural killer cells. During the sunitinib-free interval, all parameters recovered to baseline.

(C) 2010 Elsevier Masson SAS. All rights reserved.”
“It

is proposed that the human brain is proactive in that it continuously generates predictions that anticipate the relevant future. In this proposal, analogies are derived from elementary information that is extracted rapidly from the input, to link that input with the representations that exist in memory. Finding an analogical link results in the generation of focused predictions via associative activation of representations that are relevant to this analogy, in the given context. Predictions in complex buy Go 6983 circumstances, such as social interactions, combine multiple analogies. Such predictions need not be created afresh in new situations, but rather rely on existing scripts in memory, which are the result of real as well as of previously imagined experiences. This cognitive neuroscience framework provides a new hypothesis with which to consider the purpose of memory, and can help explain a variety of phenomena, ranging from recognition to first impressions, and from the brain’s ‘default mode’ to a host of mental disorders.”
“Objective-To compare the efficacy and safety of using

2 commercially available, low-magnesium, urine-acidifying dry foods to dissolve sterile struvite uroliths in bats.

Design-Prospective, multicenter, randomized clinical trial

Sample-37 cats with presumed struvite uroliths.

Procedures-Cats were randomly assigned Pevonedistat solubility dmso to be fed 1 of 2 low-magnesium, urine-acidifying dry foods (food A or B). For each cat, physical examination, urinalysis, and abdominal radiography were performed weekly to assess treatment response.

Results-32 cats had complete urolith dissolution. Mean +/- SD times for a 50% reduction in urolith size (0.69 +/- 0.1 weeks) and complete urolith dissolution (13.0 +/- 2.6 days) were significantly shorter for cats fed food A, compared with those (1.75 +/- 0.27 weeks and 270 +/- 2.6 days, respectively) for cats fed food B. At study termination, mean +/- SD urine pH (6.083 +/- 0.105) for cats fed food A was lower than

that (6.431 +/- 0.109) for cats fed food B. In 5 cats, uroliths did not dissolve and were subsequently determined to be composed of 100% ammonium urate (n = 4) or 100% calcium oxalate (1). Adverse events associated with diet were Givinostat supplier not observed in any of the cats.

Conclusions and Clinical Relevance-Results indicated that dietary dissolution is safe and effective for eradication of sterile struvite uroliths in cats. Cats fed food A had faster urolith dissolution than did cats fed food B. Lack of a reduction in urolith size at 2 weeks after diet initiation was indicative of misdiagnosis or noncompliance.”
“In this paper we investigate the magnetostrictive [(3/2)lambda(100) and (3/2)lambda(111)] and elastic (c’ and c(44)) behavior of single crystalline alloys Fe100-xMox for 2<x<12; the magnetoelastic coupling constants (-b(1) and -b(2)) are computed from the measurements.

Concentrating on the surface modifiers, one has to take into account their interaction with the matrix polymer, the solubility of the organic molecule adding to the complexity due to its influence. We aim to show that understanding the influence of surface characteristics is the basis for selecting the ideal organoclay for

the given matrix polymer. Depending on the nature of the surfactant used for the organic modification of clay and its modifier concentration see more the nanocomposites exhibit difference in the properties. The organoclays used in the present study were selected to explore the effects of the amine surfactant structure on the dispersion of clay particles in chlorobutyl rubber matrix. HDAC inhibitor mechanism The structure of the organic amine compound used to form the organoclay is expected to have some effect on the morphology and properties of the nanocomposites. (c) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011″
“Objective:

We examined the feasibility of combining communication by e-mail and self-collection of nasal swabs for the prospective detection of acute respiratory infections in a non-medical setting.

Methods: The study was conducted among a convenience sample of employees (n = 53) at a research institution (December 2009-April 2010). Real-time data on the occurrence of acute respiratory symptoms and a nasal self-swab were collected prospectively, with automated weekly e-mails as a reminder mechanism. Reverse transcription polymerase chain reaction (RT-PCR) was used to detect respiratory viral pathogens in the swabs.

Results: Fifty-one out of 53 participants completed the study. The study design S3I-201 was well accepted. Thirty (similar to 57%) participants reported at least one episode of acute respiratory infection and returned the nasal swab during the study period (eight participants reported

two episodes). The majority had no difficulties taking the self-swab and preferred this to swabbing by study personnel. Most participants obtained and returned the swabs within the recommended time. Viral respiratory pathogens were detected in 19 of 38 swabs (50%), with coronaviruses 229E/NL63 and OC43 and rhinoviruses A and B constituting 17 positive swabs (89%).

Conclusions: Combining e-mail-based symptomatic surveillance with nasal self-swabbing promises to be a powerful tool for the real-time identification of incident cases of acute respiratory infections and the associated pathogens in population-based studies. (C) 2011 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.”
“Because microRNAs regulate cancer cell differentiation, proliferation, survival and metastasis, manipulating microRNA function, either by mimicking or inhibiting miRNAs implicated in cancer, could provide a powerful therapeutic strategy to interfere with key pathways for cancer progression.

At (100) orientation, it increases linearly with increasing ion flux or energy. The findings are discussed on the basis of atomistic mechanisms of interstitial diffusion, potential lattice distortions, local decomposition, and ion-induced lattice vibrational excitations. (C) 2011 American Institute of Physics. [doi:10.1063/1.3646493]“
“Uric GSK1120212 price acid (UA) is an endogenous antioxidant. Some studies have described that multiple sclerosis (MS)

patients have lower serum UA levels than controls, although it has not been established whether UA is primarily deficient, or secondarily reduced due to its scavenging activity. UA has also been proposed as an indicator of disease activity. We, retrospectively, reviewed 478 serum UA levels obtained in 94 MS patients. Ninety samples were collected during a relapse. Correlation between UA levels obtained during a relapse or in a relapse-free period, and comparison between UA and expanded disability status scale (EDSS) score was tested using a two-tailed Student’s t test and Spearman correlation coefficients test. UA levels

were significantly lower when measured during a relapse (n 90) than in a remission period (n 368) (r -0.16, p 0.003) UA levels measured outside a relapse inversely correlated with EDSS score (r -0.15, p 0.001). Lower uric acid levels in MS patients selleckchem are associated with clinical relapse. This is the first description of an inverse correlation of serum UA levels with disability as assessed by EDSS score.”
“Nonflammability of the thermoplasticized crosslinked polyethylene (PE)/polyolefin elastomer (POE)/metal hydroxide flame retardant/compatibilizer

composites were investigated. The thermoplasticized crosslinked PE was decrosslinked from the crosslinked high-density PE under the supercritical methanol condition. Two types of metal hydroxides: aluminum hydroxide (AH) and magnesium hydroxide (MH), and a low-density polyethylene-g-maleic anhydride (LM) were used as flame retardants and a compatibilizer, respectively. Nonflammability of both PE/POE/AH/LM and PE/POE/MH/LM composites was enhanced CBL0137 with metal hydroxide flame retardant concentration. PE/POE/MH/LM composites had better nonflammability than PE/POE/AH/LM composites at the same flame retardant concentration. Interestingly, nonflammability of the composites was also strongly influenced by the compatibilizer concentration. At low compatibilizer concentration, the nonflammability of the PE/POE/MH/LM composites was improved with the compatibilizer concentration. In contrast, at high compatibilizer concentration, the nonflammability of the PE/POE/MH/LM composites was deteriorated with the compatibilizer concentration. This demonstrates that optimum concentration of the compatibilizer can help to enhance the efficiency of the flame retardants in the development of the nonflammable polyolefin for the wire and cable industry. (C) 2011 Wiley Periodicals, Inc.

The

questionnaire covered age, sex, occupation, years spent in occupation, history of NSSI during the preceding twelve months, NSSI clopidogrel administration (300 mg) (<24 Epigenetics inhibitor hours) when given with aspirin in such patients.

METHODS: We included 30,243 patients who had an acute coronary syndrome with or without ST segment elevation. Data on early clopidogrel administration were available for 24,463 (81%). Some 15,525 (51%) of the total cohort were administrated clopidogrel within 24h of admission.

RESULTS: In-hospital death occurred in 2.9% of the patients in the early clopidogrel group treated with primary PCI and in 11.4% of the patients in the other group without primary percutaneous coronary intervention (PCI) and no early clopidogrel. The unadjusted clopidogrel odds ratio (OR) for mortality was 0.31 (95% confidence interval 0.27-0.34; p < 0.001). Incidence of major adverse cardiac death (MACE) was 4.1% in the early clopidogrel group treated with 1 degrees PCI and 13.5% in the other group without primary PCI and no early clopidogrel (OR 0.35, confidence interval 0.32-0.39, p < 0.001). Early clopidogrel administration and PCI were the only treatment lowering mortality as shown by mutlivariate analysis.

CONCLUSIONS: The early administration of the antiplatelet agent BI 2536 in vitro clopidogrel in

patients with acute coronary syndromes with or without ST-segment elevation has a beneficial effect on mortality and major adverse cardiac events. The lower mortality rate and incidence of MACE emerged with a combination of primary PCI and early clopidogrel administration.”
“Polarized light (PL) sensitivity is relatively well studied in a large number of invertebrates and some fish species, but PR-171 nmr in most other vertebrate classes, including birds, the behavioural and physiological mechanism of PL sensitivity remains one of the big mysteries in sensory

biology. Many organisms use the skylight polarization pattern as part of a sun compass for orientation, navigation and in spatial orientation tasks. In birds, the available evidence for an involvement of the skylight polarization pattern in sun-compass orientation is very weak. Instead, cue-conflict and cue-calibration experiments have shown that the skylight polarization pattern near the horizon at sunrise and sunset provides birds with a seasonally and latitudinally independent compass calibration reference. Despite convincing evidence that birds use PL cues for orientation, direct experimental evidence for PL sensitivity is still lacking. Avian double cones have been proposed as putative PL receptors, but detailed anatomical and physiological evidence will be needed to conclusively describe the avian PL receptor. Intriguing parallels between the functional and physiological properties of PL reception and light-dependent magnetoreception could point to a common receptor system.