Continuous phase shift of sinusoidal signals using injection locked oscillators

This work presents an alternative to generate continuous phase shift of sinusoidal signals based on the use of super harmonic injection locked oscillators (ILO). The proposed circuit is a second harmonic ILO with varactor diodes as tuning elements. In the locking state, by changing the varactor bias, a phase shift instead of a frequency shift is observed at the oscillator output. By combining two of these circuits, relative phases up to 90 could be achieved. Two prototypes of the circuit have been implemented and tested, a hybrid version working in the range of 200-300 MHz and a multichip module (MCM) version covering the 900¿1000 MHz band.

Evidence of climatic niche shift during biological invasion

Niche-based models calibrated in the native range by relating species observations to climatic variables are commonly used to predict the potential spatial extent of species' invasion. This climate matching approach relies on the assumption that invasive species conserve their climatic niche in the invaded ranges. We test this assumption by analysing the climatic niche spaces of Spotted Knapweed in western North America and Europe. We show with robust cross-continental data that a shift of the observed climatic niche occurred between native and non-native ranges, providing the first empirical evidence that an invasive species can occupy climatically distinct niche spaces following its introduction into a new area. The models fail to predict the current invaded distribution, but correctly predict areas of introduction. Climate matching is thus a useful approach to identify areas at risk of introduction and establishment of newly or not-yet-introduced neophytes, but may not predict the full extent of invasions.

Nuclear sizes and the isotope shift

Darwin-Foldy nuclear-size corrections in electronic atoms and nuclear radii are discussed from the nuclear-physics perspective. The interpretation of precise isotope-shift measurements is formalism dependent, and care must be exercised in interpreting these results and those obtained from relativistic electron scattering from nuclei. We strongly advocate that the entire nuclear-charge operator be used in calculating nuclear-size corrections in atoms rather than relegating portions of it to the nonradiative recoil corrections. A preliminary examination of the intrinsic deuteron radius obtained from isotope-shift measurements suggests the presence of small meson-exchange currents (exotic binding contributions of relativistic order) in the nuclear charge operator, which contribute approximately 1/2%.

Hadronic vacuum polarization and the Lamb shift

Recent improvements in the determination of the running of the fine-structure constant also allow an update of the hadronic vacuum-polarization contribution to the Lamb shift. We find a shift of -3.40(7) kHz to the 1S level of hydrogen. We also comment on the contribution of this effect to the determination by elastic electron scattering of the rms radii of nuclei.

Unifying niche shift studies: insights from biological invasions.

Assessing whether the climatic niche of a species may change between different geographic areas or time periods has become increasingly important in the context of ongoing global change. However, approaches and findings have remained largely controversial so far, calling for a unification of methods. Here, we build on a review of empirical studies of invasion to formalize a unifying framework that decomposes niche change into unfilling, stability, and expansion situations, taking both a pooled range and range-specific perspective on the niche, while accounting for climatic availability and climatic analogy. This framework provides new insights into the nature of climate niche shifts and our ability to anticipate invasions, and may help in guiding the design of experiments for assessing causes of niche changes.

Shift in cytotype frequency and niche space in the invasive plant Centaurea maculosa.

Polyploidy is often assumed to increase the spread and thus the success of alien plant species, but few empirical studies exist. We tested this hypothesis with Centaurea maculosa Lam., a species native to Europe and introduced into North America approximately 120 years ago where it became highly invasive. We analyzed the ploidy level of more than 2000 plants from 93 native and 48 invasive C. maculosa populations and found a pronounced shift in the relative frequency of diploid and tetraploid cytotypes. In Europe diploid populations occur in higher frequencies than tetraploids and only four populations had both cytotypes, while in North America diploid plants were found in only one mixed population and thus tetraploids clearly dominated. Our results showed a pronounced shift in the climatic niche between tetraploid populations in the native and introduced range toward drier climate in North America and a similar albeit smaller shift between diploids and tetraploids in the native range. The field data indicate that diploids have a predominately monocarpic life cycle, while tetraploids are often polycarpic. Additionally, the polycarpic life-form seems to be more prevalent among tetraploids in the introduced range than among tetraploids in the native range. Our study suggests that both ploidy types of C. maculosa were introduced into North America, but tetraploids became the dominant cytotype with invasion. We suggest that the invasive success of C. maculosa is partly due to preadaptation of the tetraploid cytotype in Europe to drier climate and possibly further adaptation to these conditions in the introduced range. The potential for earlier and longer seed production associated with the polycarpic life cycle constitutes an additional factor that may have led to the dominance of tetraploids over diploids in the introduced range.

Staphylococcus aureus host range and human-bovine host shift.

Staphylococcus aureus is a major agent of bovine mastitis. The concomitant emergence of pig-associated methicillin-resistant S. aureus (MRSA) in human carriage and infection requires a reexamination of the host range and specificity of human- and cow-associated S. aureus strains, something which has not been systematically studied previously. The genetic relatedness of 500 S. aureus isolates from bovine mastitis cases, 57 isolates from nasal carriage of farmers, and 133 isolates from nonfarmers was determined by amplified fragment length polymorphism (AFLP) analysis and spa typing. Multilocus sequence typing (MLST) was conducted on a subset of isolates to match AFLP clusters with MLST clonal complexes (CCs). This data set allowed us to study host range and host specificity and to estimate the extent of bovine-to-human transmission. The genotype compositions of S. aureus isolates from farmers and nonfarmers were very similar, while the mastitis isolates were quite distinct. Overall, transmission was low, but specific genotypes did show increased cow-to-human transmission. Unexpectedly, more than one-third of mastitis isolates belonged to CC8, a lineage which has not been considered to be bovine mastitis associated, but it is well known from human carriage and infection (i.e., USA300). Despite the fact that we did detect some transmission of other genotypes from cows to farmers, no transmission of CC8 isolates to farmers was detected, except for one tentative case. This was despite the close genetic relatedness of mastitis CC8 strains to nonfarmer carriage strains. These results suggest that the emergence of the new bovine-adapted genotype was due to a recent host shift from humans to cows concurrent with a loss of the ability to colonize humans. More broadly, our results indicate that host specificity is a lineage-specific trait that can rapidly evolve.

Iron Supplementation Therapy in a Large Swiss Cohort of Inflammatory Bowel Disease Patients: Shift from Oral to Intravenous Therapy over Time

Background a nd A ims: T he 2 007 ECCO g uidelines o nanemia in inflammatory bowel disease (IBD) favour intravenous(iv) over oral (po) i ron supplementation due to bettereffectiveness and tolerance. Application of guidelines in clinicalpractice m ay r equire time. We a imed to determine thepercentage of IBD patients under iron supplementation therapyand its application mode over time in a large IBD cohort.Methods: Helsana, a leading Swiss health insurance companyprovides c overage f or approximately 18% of t he Swisspopulation, corresponding to about 1.2 million enrollees.Patients with Crohn's disease (CD) and ulcerative colitis (UC)were identified b y keyword search from t he a nonymisedHelsana database.Results: I n total, 6 29 CD ( 61% female) a nd 4 03 UC ( 56%female) patients w ere identified, mean retrospectiveobservation time w as 2 0.4 m onths f or CD and 13 m onths f orUC patients. Of t he entire study population, 29.3% wereprescribed iron. O ccurrence of iron prescription was 21.3% inmales a nd 31.2% in f emales ( odds r atio [OR] 1 .69, 95%-confidence interval [CI] 1.26-2.28). The prescription of iv i ronincreased from 2006/2007 ( 48.8% w ith iv i ron) to 2 008/2009(65.2% with iv iron) by a factor of 1.89.Conclusions: One third of the IBD population was treated withiron supplementation. A gradual s hift from oral t o iv iron wasobserved over time in a large Swiss IBD cohort. This switch inprescription habits g oes a long with the implementation of theECCO consensus guidelines on anemia in IBD.

Iron supplementation in a large Swiss Cohort of Inflammatory Bowel Disease patients demonstrates a shift form oral to intravenous therapy over time

Background and Aims: The 2007 European Crohn's and Colitis Organization guidelines on anemia in inflammatory bowel disease (IBD) favour intravenous (iv) over oral (po) iron supplementation due to better effectiveness and tolerance. We aimed to determine the percentage of IBD patients under iron supplementation therapy and the dynamics of prescription habits (iv versus po) over time. Methods: Helsana, a leading Swiss health insurance company provides coverage for approximately 18% of the Swiss population, corresponding to about 1.2 million enrollees. Patients with Crohn's disease (CD) and ulcerative colitis (UC) were analyzed from the anonymised Helsana database. Results: In total, 629 CD (61% female) and 398 UC (57% female) patients were identified, mean observation time was 31.8 months for CD and 31.0 months for UC patients. Of the entire study population, 27.1% were prescribed iron (21.1% in males and 31.1% in females). Patients treated with IBD-specific drugs (steroids, immunomodulators, anti-TNF agents) were more frequently treated with iron compared to patients without any medication (35.0% vs. 20.9%, OR 1.91, 95%-CI 1.41-2.61). The prescription of iv iron increased from 2006/2007 (48.8% of all patients receiving any iron priscription) to 65.2% in 2008/2009 by a factor of 1.89. Conclusions: One third of the IBD population was treated with iron supplementation. A gradual shift from oral to iv iron was observed over time. This switch in prescription habits goes along with the implementation of the ECCO consensus guidelines on anemia in IBD.

Statistical assessment of dataset shift and model portability in multi-angle in-track image acquisitions

In this study we propose an evaluation of the angular effects altering the spectral response of the land-cover over multi-angle remote sensing image acquisitions. The shift in the statistical distribution of the pixels observed in an in-track sequence of WorldView-2 images is analyzed by means of a kernel-based measure of distance between probability distributions. Afterwards, the portability of supervised classifiers across the sequence is investigated by looking at the evolution of the classification accuracy with respect to the changing observation angle. In this context, the efficiency of various physically and statistically based preprocessing methods in obtaining angle-invariant data spaces is compared and possible synergies are discussed.

Rapid genotypic change and plasticity in arbuscular mycorrhizal fungi is caused by a host shift and enhanced by segregation.

Arbuscular mycorrhizal fungi (AMF) are among the most abundant symbionts of plants, improving plant productivity and diversity. They are thought to mostly grow vegetatively, a trait assumed to limit adaptability. However, AMF can also harbor genetically different nuclei (nucleotypes). It has been shown that one AMF can produce genotypically novel offspring with proportions of different nucleotypes. We hypothesized that (1) AMF respond rapidly to a change of environment (plant host) through changes in the frequency of nucleotypes; (2) genotypically novel offspring exhibit different genetic responses to environmental change than the parent; and (3) genotypically novel offspring exhibit a wide range of phenotypic plasticity to a change of environment. We subjected AMF parents and offspring to a host shift. We observed rapid and large genotypic changes in all AMF lines that were not random. Genotypic and phenotypic responses were different among offspring and their parents. Even though growing vegetatively, AMF offspring display a broad range of genotypic and phenotypic changes in response to host shift. We conclude that AMF have the ability to rapidly produce variable progeny, increasing their probability to produce offspring with different fitness than their parents and, consequently, their potential adaptability to new environmental conditions. Such genotypic and phenotypic flexibility could be a fast alternative to sexual reproduction and is likely to be a key to the ecological success of AMF.

Loss of mating flight and shift in the pattern of carbohydrate storage in sexuals of ants (Hymenoptera; Formicidae)

In ants, energy for flying is derived from carbohydrates (glycogen and free sugars). The amount of these substrates was compared in sexuals participating or not participating in mating flights. Results show that in participating females (Lasius niger, L. flavus, Myrmica scabrinodis, Formica rufa, F. polyctena, F. lugubris), the amount of carbohydrates, especially glycogen, was higher than in non-participating females (Cataglyphis cursor, Iridomyrmex humilis). Similarly, male C. cursor and I. humilis which fly, exhibit a much higher carbohydrate content than do the non-flying females of these species. Furthermore, the quantity of carbohydrates stored was generally higher in males than in females for each species. These results are discussed with regard to the loss of the nuptial flight by some species of ants.

Prolonged fluconazole exposure leads to a shift to Candida species with decreased susceptibility in breakthrough candidemia: prospective survey of the Fungal Infection Network of Switzerland

Objectives: To compare the clinical characteristics, species distribution and antifungal susceptibility of Candida bloodstream isolates (BSI) in breakthrough (BTC) vs. non-breakthrough candidemia (NBTC) and to study the effect of prolonged vs. short fluconazole (F) exposure in BTC.Methods: Candida BSI were prospectively collected during 2004- 2006 from 27 hospitals (seven university, 20 affiliated) of the FUNGINOS network. Susceptibility to F, voriconazole (V) and caspofungin (C) was tested in the FUNGINOS mycology reference laboratory by microtitre broth dilution method with the Sensititre YeastOneTM test panel. Clinical data were collected using standardized CRFs. BTC was defined as occurring during antifungal treatment/prophylaxis of at least three days duration prior to the candidemia. Susceptibility of BSI was defined according to 2010/2011 CLSI clinical breakpoints.Results: Out of 567 candidemia episodes, 550 Candida BSI were available. Of these, 43 (7.6%) were from BTC (37/43, 86% were isolated after F exposure). 38 BTC (88.4%) and 315 NBTC (55.6%) occurred in university hospitals (P < 0.001). The majority of patients developing BTC were immunocompromised: higher proportions of haematological malignancies (62.8% in BTC vs. 47.1% in NBTC, P < 0.001), neutropenia (37.2% vs. 11.8%, P < 0.001), acute GvHD (14% vs. 0.2%, P < 0.001), immunosuppressive drugs (74.4% vs. 7.8%, P < 0.001), and mucositis (32.6% vs. 2.3%, P < 0.001) were observed. Other differences between BTC and NBTC were higher proportions of patients with central venous catheters in the 2 weeks preceding candidemia (95.3% vs. 83.4%, P = 0.047) and receiving total parenteral nutrition (62.8% vs. 35.9%, P < 0.001), but a lower proportion of patients treated with gastric proton pump inhibitors (23.3% vs. 72.1%, P < 0.001). Overall mortality of BTC and NBTC was not different (34.9% vs. 31.7%, P = 0.73), while a trend to higher attributable mortality in BTC was found (13.9% vs. 6.9%, P = 0.12). Species identification showed a majority of C. albicans in both groups (51.2% in BTC vs. 62.9% in NBTC, P = 0.26), followed by C. glabrata (18.6% vs. 18.5%), C. tropicalis (2.3% vs. 6.3%) and C. parapsilosis (7.0% vs. 4.7%). Significantly more C. krusei were detected in BTC versus NBTC (11.6% vs. 1.6%, P = 0.002). The geometric mean MIC for F, V and C between BTC and NBTC isolates was not significantly different. However, in BTC there was a significant association between duration of F exposure and the Candida spp.: >10 days of F was associated with a significant shift from susceptible Candida spp. (C. albicans, C. parapsilosis, C. tropicalis, C. famata) to non-susceptible species (C. glabrata, C. krusei, C. norvegensis). Among 21 BTC episodes occurring after £10 days of F, 19% of the isolates were non-susceptible, in contrast to 68.7% in 16 BTC episodes occurring after >10 days of F (P = 0.003).Conclusions: Breakthrough candidemia occurred more often in immunocompromised hosts. Fluconazole administered for >10 days was associated with a shift to non-susceptible Candida spp.. Length of fluconazole exposure should be taken into consideration for the choice of empirical antifungal treatment.