Though seemingly bizarre, the dramatic morphological and ecological transformation that occurs when immature life stages metamorphose into reproductive adults is one of the most successful ...developmental strategies on the planet. The adaptive decoupling hypothesis (ADH) proposes that metamorphosis is an adaptation for breaking developmental links between traits expressed in different life stages, thereby facilitating their independent evolution when exposed to opposing selection pressures. Here, we draw inspiration from the ADH to develop a conceptual framework for understanding changes in gene expression across ontogeny. We hypothesized that patterns of stage‐biased and sex‐biased gene expression are the product of both decoupling mechanisms and selection history. To test this hypothesis, we characterized transcriptome‐wide patterns of gene‐expression traits for three ecologically distinct larval stages (all male) and adult males and females of a hypermetamorphic insect (Neodiprion lecontei). We found that stage‐biased gene expression was most pronounced between larval and adult males, which is consistent with the ADH. However, even in the absence of a metamorphic transition, considerable stage‐biased expression was observed among morphologically and behaviourally distinct larval stages. Stage‐biased expression was also observed across ecologically relevant Gene Ontology categories and genes, highlighting the role of ecology in shaping patterns of gene expression. We also found that the magnitude and prevalence of stage‐biased expression far exceeded adult sex‐biased expression. Overall, our results highlight how the ADH can shed light on transcriptome‐wide patterns of gene expression in organisms with complex life cycles. For maximal insight, detailed knowledge of organismal ecology is also essential.
The increasing availability of long-term observational data can lead to the
development of innovative modelling approaches to determine landslide
triggering conditions at a regional scale, opening ...new avenues for landslide
prediction and early warning. This research blends the strengths of existing approaches with the capabilities of generalized additive mixed models
(GAMMs) to develop an interpretable approach that identifies seasonally
dynamic precipitation conditions for shallow landslides. The model builds
upon a 21-year record of landslides in South Tyrol (Italy) and separates
precipitation that induced landslides from precipitation that did not. The
model accounts for effects acting at four temporal scales: short-term
“triggering” precipitation, medium-term “preparatory” precipitation,
seasonal effects, and across-year data variability. It provides relative
landslide probability scores that were used to establish seasonally dynamic
thresholds with optimal performance in terms of hit and false-alarm rates,
as well as additional thresholds related to user-defined performance scores.
The GAMM shows a high predictive performance and indicates that more
precipitation is required to induce a landslide in summer than in
winter/spring, which can presumably be attributed mainly to vegetation and
temperature effects. The discussion illustrates why the quality of input
data, study design, and model transparency are crucial for landslide
prediction using advanced data-driven techniques.
Progress towards a large area, thin DEPFET detector module Fischer, P.; Andricek, L.; Herrmann, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2007, Letnik:
582, Številka:
3
Journal Article
Recenzirano
Large arrays of depleted field effect transistor (DEPFET) detector elements are one possible technology for the vertex detector of the planned International Linear Collider. The main challenges are ...the production of large
(
10
cm
2
)
devices with an average thickness of around
100
μ
m
(silicon) and their fast column parallel readout. This paper describes in some detail how a DEPFET based sensor module could be built and presents the design of the latest generation of ‘Switcher’ steering chips.
Active pixel sensors (APS) based on the depleted P-channel MOSFET (DEPMOSFET) recently produced at the MPI semiconductor laboratory are a promising new type of sensor to cope with the advanced ...requirements of the XEUS wide field imager, a large area imaging and spectroscopy detector for X-ray astronomy. The DEPMOSFET APS combine high energy resolution, low power consumption and random accessibility of pixels providing for highly flexible readout modes with fast readout speed. In the first prototype production, several design variants of 64/spl times/64 pixel DEPMOSFET matrices with a pixel size of 75/spl times/75 /spl mu/m/sup 2/ have been realized. A data acquisition (DAQ) system for evaluation of sensor prototypes has been developed, which allows for a performance characterization of the different designs. For operation, DEPMOSFET device, front-end IC and control ICs are integrated onto a readout hybrid. Device readout is done row by row, addressing and resetting one single matrix row at a time and processing the signals with a 64 channel parallel CMOS amplifier/multiplexer IC of the charge amplifier multiplexer type applying 8-fold correlated double sampling. Addressing and resetting of the matrix rows is done by two control ICs of the SWITCHER type fabricated in a high voltage CMOS technology. A number of readout hybrids has been built, the characterization of the different devices in terms of noise, spectral resolution and charge collection efficiency is in progress. The most promising DEPMOSFET matrix design variants, the DAQ system and measured key performance parameters of the devices are presented.
A DePMOS structure provides detection and amplification jointly, and it is free of interconnection stray capacitance. To fully exploit the intrinsic low noise of the device an electrical model has ...been developed. The most relevant parameters have been measured in order to choose an adequate readout electronics. DePMOS can operate in continuous mode, i.e., without applying any clear pulse during the signal processing, and can be read out by a time-continuous shaper amplifier. An unequalled noise of 2.2 electrons rms at room temperature has been measured. In this mode DePMOS can be used, for example, as the readout device for silicon drift detectors. Anyway , DePMOS was developed to be the basic element of an active pixel sensor suitable to cope with the requirements of the XEUS Wide Field Imager. In a matrix arrangement, each pixel must be read out by a time-variant filter. A multichannel integrated shaping amplifier, based on multicorrelated double sampling, has been designed. Spectroscopic resolution obtained filtering the pixel matrix with this readout chip is in agreement with measurements in continuous mode and matches the predictions of the model presented. It has also been experimentally proved that the clear procedure does not introduce additional noise contribution, even in the very low noise range achieved. This qualifies DePMOS as a "reset-noise-free" device
Knowing the source and runout of debris flows can help in planning strategies aimed at mitigating these hazards. Our research in this paper focuses on developing a novel approach for optimizing ...runout models for regional susceptibility modelling, with a case study in the upper Maipo River basin in the Andes of Santiago, Chile. We propose a two-stage optimization approach for automatically selecting parameters for estimating runout path and distance. This approach optimizes the random-walk and Perla et al.'s (PCM) two-parameter friction model components of the open-source Gravitational Process Path (GPP) modelling framework. To validate model performance, we assess the spatial transferability of the optimized runout model using spatial cross-validation, including exploring the model's sensitivity to sample size. We also present diagnostic tools for visualizing uncertainties in parameter selection and model performance. Although there was considerable variation in optimal parameters for individual events, we found our runout modelling approach performed well at regional prediction of potential runout areas. We also found that although a relatively small sample size was sufficient to achieve generally good runout modelling performance, larger samples sizes (i.e. ≥80) had higher model performance and lower uncertainties for estimating runout distances at unknown locations. We anticipate that this automated approach using the open-source R software and the System for Automated Geoscientific Analyses geographic information system (SAGA-GIS) will make process-based debris-flow models more readily accessible and thus enable researchers and spatial planners to improve regional-scale hazard assessments.
For the detection of secondary vertices of long lived particles containing bottom and charm quarks at the International Linear Collider (ILC), a DEPFET pixel detector is one of the technologically ...favored options. In a DEPFET sensor a MOSFET pixel detector is integrated on a sidewards depleted silicon bulk sensor, thus combining the advantages of a fully depleted silicon sensor with in-pixel amplification. DEPFET pixel matrices have been characterized in a high energy particle beam. Since the DEPFET is a very high precision device, given its large S/N (> 100) and small pixel size (36 × 22 ¿m 2 ), a DEPFET based pixel telescope consisting of 5 DEPFETs has been developed. The uncertainty on the predicted position for a device under test (DUT) positioned inside the telescope was found to be 1.4 ¿m with the existing device, due to the limited performance of two of the five DEPFET planes. A DEPFET telescope built of 5 modules equivalent to the best plane presented here, would have a track extrapolation error as low as 0.65 ¿m at the DUT plane.
DEPFET pixel detectors are unique devices in terms of energy and spatial resolution because very low noise operation can be obtained (ENC=2.2e/sup -/ at room temperature) by implementing the ...amplifying transistor in the pixel cell itself. Full DEPFET pixel matrices have been built and operated for autoradiographical imaging with imaging resolutions of 4.3/spl plusmn/0.8 /spl mu/m at 22 keV. For applications in low energy X-ray astronomy the high energy resolution of DEPFET detectors is attractive. For particle physics, DEPFET pixels are interesting as low mass detectors with high spatial resolution. For a linear collider detector the readout must be very fast. New readout chips have been designed and produced for the development of a DEPFET module for a pixel detector at the proposed TESLA collider, containing 520/spl times/4000 pixels, with 50 MHz line rate and 25 kHz frame rate. The circuitry contains current memory cells and current hit scanners for fast pedestal subtraction and sparsified readout. The imaging performance of DEPFET devices as well as present achievements toward a DEPFET vertex detector for a linear collider are presented.
For operation at a linear collider the excellent noise performance of depleted field effect transistor (DEPFET) pixels allows building very thin detectors with high spatial resolution and low power ...consumption. However, high readout speeds of 50 MHz line rate and 20 kHz for the full detector must be reached. A prototype system is presented, using a new DEPFET pixel matrix (128 /spl times/ 64 pixels), fast steering chips (Switcher II) for row wise operation and a fast current based readout chip (CURO II). The sensors with small linear DEPFET pixels (22/spl times/36 /spl mu/m/sup 2/) are optimized for fast readout and high spatial resolution. Measurements show that the complete removal of the accumulated signal charge from the internal gate (complete clear), which is fundamental for the foreseen readout mode, is feasible. The current based readout chip CUROII, containing current memory cells, pedestal subtraction and on chip zero suppression for a triggerless operation has been fabricated and tested. First results of a full prototype system are presented.
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