37 research outputs found
Towards Automatic Detection of Animals in Camera-Trap Images
In recent years the world's biodiversity is declining on an unprecedented scale. Many species are endangered and remaining populations need to be protected. To overcome this agitating issue, biologist started to use remote camera devices for wildlife monitoring and estimation of remaining population sizes. Unfortunately, the huge amount of data makes the necessary manual analysis extremely tedious and highly cost intensive. In this paper we re-train and apply two state-of-the-art deep-learning based object detectors to localize and classify Serengeti animals in camera-trap images. Furthermore, we thoroughly evaluate both algorithms on a self-established dataset and show that the combination of the results of both detectors can enhance overall mean average precision. In contrast to previous work our approach is not only capable of classifying the main species in images but can also detect them and therefore count the number of individuals which is in fact an important information for biologists, ecologists, and wildlife epidemiologists
Replication of Wolford et al. (2004, CJEP, Exp. 1)
Replication of Experiment 1 of Wolford, Newman, Miller, & Wig (2004), "Searching for patterns in random sequences," Canadian Journal of Experimental Psychology, 58(4), 221-228
Beitraege zu Ergebnissen demografischer Forschung und zur Herausbildung und Entwicklung des Leitungs- und Planungssystems der DDR
SIGLEIAB-32121-DD AT 902 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman
Bcl-xL is an oncogenic driver in colorectal cancer
Colorectal cancer (CRC) is the second most common malignant neoplasia in women and men worldwide. The B-cell lymphoma 2 (Bcl-2) protein family is mainly known for its pivotal role in the regulation of the mitochondrial death pathway. Anti-apoptotic Bcl-2 proteins may provide survival benefits and induce therapy resistance in cancer cells. Among anti-apoptotic Bcl-2 proteins, we found solely Bcl-xL strongly upregulated in human CRC specimens. In order to study protein function in the context of tumor initiation and progression in vivo, we generated a mouse model lacking Bcl-xL in intestinal epithelial cells (Bcl-xL(IEC-KO)). If challenged in an inflammation-driven tumor model, Bcl-xL(IEC-KO) mice showed a significantly reduced tumor burden with lower tumor numbers per animal and decreased tumor sizes. Analysis of cell death events by immunohistochemistry and immunoblotting revealed a striking increase of apoptosis in Bcl-xL-negative tumors. qRT-PCR and immunohistochemistry excluded changes in proliferative capacity and immune cell infiltration as reasons for the reduced tumor load and thereby identify apoptosis as key mechanism. Human CRC tissue was cultured ex vivo and treated with the small molecule compound ABT-737, which inhibits Bcl-xL and Bcl-2. Under ABT-737 treatment, the amount of apoptotic tumor cells significantly increased compared with controls, whereas proliferation levels remained unaltered. In summary, our findings identify Bcl-xL as a driver in colorectal tumorigenesis and cancer progression, making it a valuable target for clinical application
Beyond cell death - antiapoptotic Bcl-2 proteins regulate migration and invasion of colorectal cancer cells in vitro.
Migration and invasion of malignant cells are prerequisites for cancer progression and metastasis. The Bcl-2 family of proteins consists of about 25 members and has been extensively studied in the context of apoptosis. Despite the fact that small molecules targeting Bcl-2 proteins have already entered clinical trials, very few studies investigated a role of antiapoptotic Bcl-2 proteins beside cell death in the context of metastasis. The aim of this study was to dissect a potential role of the antiapoptotic Bcl-2 proteins Mcl-1, Bcl-2 and Bcl-xL on migration and invasion of colorectal cancer cells independent of their cell death control function. We used migration and invasion assays as well as three dimensional cell cultures to analyze colorectal cancer cell lines (HT29 and SW480) after siRNA mediated knockdown or overexpression of Mcl-1, Bcl-2 or Bcl-xL. We observed neither spontaneous cell death induction nor impaired proliferation of cells lacking Mcl-1, Bcl-2 or Bcl-xL. In contrast, knockdown of Mcl-1 led to increased proliferation. Strikingly, we demonstrate a profound impairment of both, migration and invasion, of colorectal cancer cells after Mcl-1, Bcl-2 or Bcl-xL knockdown. This phenotype was completely revised in cells overexpressing Mcl-1, Bcl-2 or Bcl-xL. The most pronounced effect among the investigated proteins was observed for Bcl-2. The data presented indicate a pivotal role of Mcl-1, Bcl-2 and Bcl-xL for migration and invasion of colorectal cancer cells independent of their known antiapoptotic effects. Thus, our study illustrates novel antitumoral mechanisms of Bcl-2 protein targeting
Pan-Bcl-2 Inhibitor Obatoclax Delays Cell Cycle Progression and Blocks Migration of Colorectal Cancer Cells
<div><p>Despite the fact that new treatment regimes have improved overall survival of patients challenged by colorectal cancer (CRC), prognosis in the metastatic situation is still restricted. The Bcl-2 family of proteins has been identified as promising anti cancer drug target. Even though small molecules targeting Bcl-2 proteins are in clinical trials, little is known regarding their effects on CRC. The aim of this study was to preclinically investigate the value of ABT-737 and Obatoclax as anticancer drugs for CRC treatment. The effects of the BH3-mimetics ABT-737 and Obatoclax on CRC cells were assessed using viability and apoptosis assays. Wound healing migration and boyden chamber invasion assays were applied. 3-dimensional cell cultures were used for long term assessment of invasion and proliferation. Clinically relevant concentrations of pan-Bcl-2 inhibitor Obatoclax did not induce cell death. In contrast, the BH3-mimetic ABT-737 induced apoptosis in a dose dependent manner. Obatoclax caused a cell line specific slowdown of CRC cell growth. Furthermore, Obatoclax, but not ABT-737, recovered E-Cadherin expression and led to impaired migration and invasion of CRC cells. The proliferative capacity and invasiveness of CRC cells was strikingly inhibited by low dose Obatoclax in long term 3-dimensional cell cultures. Obatoclax, but not ABT-737, caused a G1-phase arrest accompanied by a downregulation of Cyclin D1 and upregulation of p27 and p21. Overexpression of Mcl-1, Bcl-x<sub>L</sub> or Bcl-2 reversed the inhibitory effect of Obatoclax on migration but failed to restore the proliferative capacity of Obatoclax-treated CRC cells. The data presented indicate broad and multifaceted antitumor effects of the pan-Bcl-2 inhibitor Obatoclax on CRC cells. In contrast to ABT-737, Obatoclax inhibited migration, invasion and proliferation in sublethal doses. In summary, this study recommends pan-Bcl-2 inhibition as a promising approach for clinical trials in CRC.</p></div
Maximizing as satisficing: On pattern matching and probability maximizing in groups and individuals
Distinguishing meaningful structure from unpredictable randomness is a key challenge in many domains of life. We examined whether collaborating three-person groups (n = 81) outperform individuals (n = 81) in facing this challenge with a two-part repeated choice task, where outcomes were either serially independent (probabilistic part) or fixed in a particular sequence (pattern part). Groups performed as well as the best individuals in the probabilistic part but groups' accuracy did not credibly exceed that of the average individual in the pattern part. Qualitative coding of group discussion data revealed that failures to identify existing patterns were related to groups accepting probability maximizing as a “good enough” strategy rather than expending effort to search for patterns. These results suggest that probability maximizing can arise via two routes: recognizing that probabilistic processes cannot be outdone (maximizing as optimizing) or settling for an imperfect but easily implementable strategy (maximizing as satisficing).publishe