SPATIAL-SPECTRAL UNMIXING OF HYPERSPECTRAL DATA FOR DETECTION AND ANALYSIS OF ASTROPHYSICAL SOURCES WITH THE MUSE INSTRUMENT

International audienceDetection and analysis of astrophysical sources from the forthcoming MUSE instrument is of greatest challenge mainly due to the high noise level and the three-dimensional translation variant blur effect of MUSE data. In this work, we use some realistic hypotheses of MUSE to reformulate the data convolution model into a set of linear mixing models corresponding to different, disjoint spectral frames. Based on the linear mixing models, we propose a spatial-spectral unmixing (SSU) algorithm to detect and characterize the galaxy spectra. In each spectral frame, the SSU algorithm identifies the pure galaxy regions with a theoretical guarantee, and estimate spectra based on a sparse approximation assumption. The full galaxy spectra can finally be recovered by concatenating the spectra estimates associated with all the spectral frames. The simulations were performed to demonstrate the efficacy of the proposed SSU algorithm

Regulation of PERK Signaling and Leukemic Cell Survival by a Novel Cytosolic Isoform of the UPR Regulator GRP78/BiP

The unfolded protein response (UPR) is an evolutionarily conserved mechanism to allow cells to adapt to stress targeting the endoplasmic reticulum (ER). Induction of ER chaperone GRP78/BiP increases protein folding capacity; as such it represents a major survival arm of UPR. Considering the central importance of the UPR in regulating cell survival and death, evidence is emerging that cells evolve feedback regulatory pathways to modulate the key UPR executors, however, the precise mechanisms remain to be elucidated. Here, we report the fortuitous discovery of GRP78va, a novel isoform of GRP78 generated by alternative splicing (retention of intron 1) and alternative translation initiation. Bioinformatic and biochemical analyses revealed that expression of GRP78va is enhanced by ER stress and is notably elevated in human leukemic cells and leukemia patients. In contrast to the canonical GRP78 which is primarily an ER lumenal protein, GRP78va is devoid of the ER signaling peptide and is cytosolic. Through specific knockdown of endogenous GRP78va by siRNA without affecting canonical GRP78, we showed that GRP78va promotes cell survival under ER stress. We further demonstrated that GRP78va has the ability to regulate PERK signaling and that GRP78va is able to interact with and antagonize PERK inhibitor P58IPK. Our study describes the discovery of GRP78va, a novel cytosolic isoform of GRP78/BiP, and the first characterization of the modulation of UPR signaling via alternative splicing of nuclear pre-mRNA. Our study further reveals a novel survival mechanism in leukemic cells and other cell types where GRP78va is expressed

A Load-based Power Saving and Scheduling Scheme in IEEE 802.16e

[[abstract]]論文摘要 802.16網路中，是由Base Station(BS)以及fixed Subscriber Station(SS)所組成的，在2005年的時候提出了一個最新版本的標準:802.16e-20006,為SS增加了mobility的功能，並為SS命名為mobile Subscriber Station(MSS)。由於SS增加了mobility的功能，所以power saving便是802.16e的一大課題。也因此在標準中為不同類型的connection定義出三種類型的power saving機制: Type I, Type II, 以及Type III。目前有許多的研究根據Type I或 Type II不足的地方做改善，以提升power efficiency。然而我們發現到，無論是standard所提出的power saving機制或是其他一些相關研究都無法在面對現實動態traffic load的時候達到很好的省電效能。這主要是因為這些機制大部分都是被動地控制MSS的sleeping pattern，並沒有主動去掌握traffic的流量以及特性來決定MSS的睡眠時間。 在我們先前的研究中，是針對Std_type III做機制上的改良，概念是根據網路情況的power saving，稱之Load-Based Power saving(LBPS)。LBPS的基本想法是：我們會先量測MSS的traffic，並根據MSS當下的traffic特性來決定MSS的sleep window size。這也就表示LBPS機制下的power efficiency會比以Type I或 Type II為基礎的機制還要好。由於先前提出的機制假設所有MSS所計算出來的sleep window size都一樣，因此所有的MSS都會同時醒來清資料，並同時進入到sleep的狀態，所以此機制稱為：LBPS-Sync。 在這篇倫文中，我們提出了基於LBPS-Sync下的兩種機制: LBPS-Split及LBPS-Merge。在這兩項機制中，我們移除了MSS同步的假設，因此BS為每一個MSS排程的睡眠時間可以更有彈性，讓整體的power efficiency變的更好。 在這兩項機制排程的時候，會使用不同的方法為MSS分組。由模擬結果顯示，這兩項機制的power saving勝過LBPS-Sync。未來的研究中，我們將加入有delay限制的traffic，像是UGS以及rtPS，做power saving上的探討。[[abstract]]Abstract An IEEE 802.16-2004 network is composed of one Base Station (BS) and some fixed Subscriber Stations (SS). An amendment to 802.16-2004 addressing mobility was proposed in 2005 and the newest version of the standard is IEEE 802.16e-2006, in which SS is named Mobile Subscriber Station (MSS). Mobility of MSS has introduced the issue of powering saving, and three classes of power saving, Type I, Type II, and Type III, were specified in the standard. Many researchers have been focusing on modeling or improvement of power saving based on Type I or Type II. However, we have found that neither the standards nor the extension works can achieve good performance to deal with the dynamic nature of traffic load. The main reason is that most of the mechanisms in a sense adopted the passive way of control in which the sleeping pattern is shaped passively by the result of the previous sleeping cycle without any information about traffic load or characteristics. In our previous work, as an extension of Type III, the idea of traffic-aware power saving, namely Load-Based Power Saving (LBPS) was proposed. The basic idea of LBPS is to model and measure traffic proactively, and the size of the sleep window is then determined by traffic characteristics obtained. It was demonstrated that better power efficiency can be achieved by LBPS than Type-I or Type-II based schemes. Since the previously proposed scheme assumed that all MSS awake and sleep at the same time in calculation of the sleep window size, it is called LBPS-Sync. In this thesis, two enhancements of LBPS-Sync, namely LBPS-Split and LBPS-Merge, are proposed. The assumption of synchronously awaking and sleeping of MSS is removed in the enhancements so that BS can have more flexibility to schedule the sleep time of each MSS for better power efficiency. The two enhancements are based on two different strategies to cluster MSS in scheduling Simulation study has demonstrated that both of the proposed schemes outperform LBPS-Sync in power saving. Future work of the research is to further extend the schemes by incorporating delay-sensitive traffic such as UGS and rtPS in power saving.[[note]]碩

SPATIAL-SPECTRAL UNMIXING OF HYPERSPECTRAL DATA FOR DETECTION AND ANALYSIS OF ASTROPHYSICAL SOURCES WITH THE MUSE INSTRUMENT

Detection and analysis of astrophysical sources from the forthcoming MUSE instrument is of greatest challenge mainly due to the high noise level and the three-dimensional translation variant blur effect of MUSE data. In this work, we use some realistic hypotheses of MUSE to reformulate the data convolution model into a set of linear mixing models corresponding to different, disjoint spectral frames. Based on the linear mixing models, we propose a spatial-spectral unmixing (SSU) algorithm to detect and characterize the galaxy spectra. In each spectral frame, the SSU algorithm identifies the pure galaxy regions with a theoretical guarantee, and estimate spectra based on a sparse approximation assumption. The full galaxy spectra can finally be recovered by concatenating the spectra estimates associated with all the spectral frames. The simulations were performed to demonstrate the efficacy of the proposed SSU algorithm

Data from: Fishing-induced changes in adult length are mediated by skipped-spawning

Elucidating fishing effects on fish population dynamics is a critical step toward sustainable fisheries management. Despite previous studies that have suggested age or size truncation in exploited fish populations, other aspects of fishing effects on population demography, e.g., via altering life histories and density, have received less attention. Here, we investigated the fishing effects altering adult demography via shifting reproductive trade-offs in the iconic, overexploited, Pacific bluefin tuna Thunnus orientalis. We found that, contrary to our expectation, mean lengths of catch increased over time in longline fisheries. On the other hand, mean catch lengths for purse seine fisheries did not show such increasing trends. We hypothesized that the size-dependent energetic cost of the spawning migration and elevated fishing mortality on the spawning grounds potentially drive size-dependent skipped spawning for adult tuna, mediating the observed changes in the catch lengths. Using eco-genetic individual-based modeling, we demonstrated that fishing-induced evolution of skipped spawning and size truncation interacted to shape the observed temporal changes in mean catch lengths for tuna. Skipped spawning of the small adults led to increased mean catch lengths for the longline fisheries, while truncation of small adults by the purse seines could offset such a pattern. Our results highlight the eco-evolutionary dynamics of fishing effects on population demography and caution against using demographic traits as a basis for fisheries management of the Pacific bluefin tuna as well as other migratory species

Life histories determine divergent population trends for fishes under climate warming

Most marine fish species express life-history changes across temperature gradients, such as faster growth, earlier maturation, and higher mortality at higher temperature. However, such climate-driven effects on life histories and population dynamics remain unassessed for most fishes. For 332 Indo-Pacific fishes, we show positive effects of temperature on body growth (but with decreasing asymptotic length), reproductive rates (including earlier age-at-maturation), and natural mortality for all species, with the effect strength varying among habitat-related species groups. Reef and demersal fishes are more sensitive to temperature changes than pelagic and bathydemersal fishes. Using a life table, we show that the combined changes of life histories upon increasing temperature tend to facilitate population growth for slow life-history populations, but reduce it for fast life-history ones. Within our data, lower proportions (25–30%) of slow life-history fishes but greater proportions of fast life-history fishes (42–60%) show declined population growth rates under 1 °C warming. Together, these findings suggest prioritizing sustainable management for fast life-history species

BFspawner_mean_length_data

This file contains the time series of mean catch length data of adult Pacific bluefin tuna based on three fisheries: Taiwanese longline (TWL), Japanese coastal longline (JCL), and Japanese purse seine (JPS). The unit of length is cm. FYEAR: fishing year. Description of the sampling methods is available in the Material and Methods of the paper and supplemental material Table S1