Incentives and Gender in a Multi-task Setting: an Experimental Study with Real-Effort Tasks

This paper investigates the behavioural effects of competitive, social-value and social-image incentives on men’s and women’s allocation of effort in a multi-task environment. Specifically, using two real-effort laboratory tasks, we investigate how competitive prizes, social-value generation and public awards affect effort allocation decisions between the tasks. We find that all three types of incentives significantly focus effort allocation towards the task they are applied in, but the effect varies significantly between men and women. The highest effort distortion lies with competitive incentives, which is due to the effort allocation decision of men. Women exert similar amount of effort across the three incentive conditions, with slightly lower effort levels in the social-image incentivized tasks. Our results inform how and why genders differences may persist in competitive workplaces

Evaporation of high speed sporadic meteors

International audienceRecent measurements conducted at the Arecibo Observatory report high-speed sporadic meteors having velocities near 50 km/s. The results seem to indicate a bimodal velocity distribution in the sporadic meteors (maxima at ~20 km/s and ~50 km/s). The particles have a maximum mass of ~1 ?g. This paper will present an analysis of the ablation of 1 ?g meteoroids having velocities of 20, 30, 50, and 70 km/s. The calculations show that there is fractionation even for the fast meteoroids, the effect being particularly noticeable for the 1 ?g sporadic particles, and less so for the heavier particles. The relevance of the calculations to the radar observations of the sporadic meteors will be discussed

Artificial dielectric optical structures: A challenge for nanofabrication

Diffractive optical components can be made using multiple level kinoforms or single level artificial dielectric structures. The latter require the fabrication of pillars of equal depth but differing width and spacing. As a demonstration device, the diffractive optic equivalent of a wedge has been made in GaAs for use at 1.15 μm. The need for all pillars to have the same height was met by using a selective etch and a very thin etch-stop layer on AlGaAs. The experimental diffraction efficiency was 87.8%, among the best ever obtained and close to the theoretical maximum of 97.6%. © 1998 American Vacuum Society

Photometric analysis of a space shuttle water venting

Presented here is a preliminary interpretation of a recent experiment conducted on Space Shuttle Discovery (Mission STS 29) in which a stream of liquid supply water was vented into space at twilight. The data consist of video images of the sunlight-scattering water/ice particle cloud that formed, taken by visible light-sensitive intensified cameras both onboard the spacecraft and at the AMOS ground station near the trajectory's nadir. This experiment was undertaken to study the phenomenology of water columns injected into the low-Earth orbital environment, and to provide information about the lifetime of ice particles that may recontact Space Shuttle orbits later. The findings about the composition of the cloud have relevance to ionospheric plasma depletion experiments and to the dynamics of the interaction of orbiting spacecraft with the environment

An approach for an automatic fracture detection of skull DICOM images based on neighboring pixels

Providing easy access to Picture Archiving and Communications Systems (PACS) of selected image slices based on its diagnosis would be useful to teach medical students and educators and for government policies. This requires a simplified retrieval presenting only the key images to the doctors that has the diagnosis for every study of interest, thus saving doctors time. An automatic detection of diagnosis will help the radiographers in saving time since they consume a lot of time in the process of detecting skull fractures manually and with the automatic annotation of the pathological terms only to the key slices that has findings/diagnosis of the entire image set an efficient retrieval of specific key slices can be achieved. One important abnormality in the skull is its fracture. The proposed research goal concentrates on the automatic detection of normal and abnormal skull images as a part of our work. This paper presents a simple and fast automatic method to detect skull fracture in Digital Imaging and Communications in Medicine (DICOM) to extract the skull bone using histogram based thresholding and with the neighboring pixel connectivity search to identify the fracture. The experimental results of this approach are reliable with high detection rate

Fitness costs associated with infections of secondary endosymbionts in the cassava whitefly species Bemisia tabaci

We investigated the dual effects of bacterial infections and diseased cassava plants on the fitness and biology of the Bemisia tabaci infesting cassava in Africa. Isofemale B. tabaci colonies of sub-Saharan Africa 1-subgroup 3 (SSA1-SG3), infected with two secondary endosymbiotic bacteria Arsenophonus and Rickettsia (AR+) and those free of AR infections (AR-) were compared for fitness parameters on healthy and East African cassava mosaic virus-Uganda variant (EACMV-UG) infected cassava plants. The whitefly fecundity and nymph development was not affected by bacterial infections, or the infection of cassava by the virus. However, emergence of adults from nymphs was 50% and 17% higher by AR- on healthy and virus-infected plants, respectively than AR+ flies. Development time of adults also was 10 days longer in AR+ than AR-. The whiteflies were further compared for acquisition and retention of East African cassava mosaic virus-Uganda (EACMV-UG). Higher proportion of AR- acquired (91.8%) and retained (87.6%) the virus than AR+ (71.8%, 61.2%, respectively). Similarly, the AR- flies retained higher quantities of virus (~9 folds more) than AR+. These results indicated that bacteria-free whiteflies were superior and better transmitters of EACMV-UG, as they had higher adult emergence, quicker life-cycle and better virus retention abilities than those infected with bacteria

Colorectal Liver Metastases

The diagnosis and management of CRLM is complex and requires a multidisciplinary team approach for optimal outcomes. Over the past several decades, the 5-year survival following resection of CRLM has increased and the criteria for resection have broadened substantially. Even patients with multiple, bilateral CRLM, previously thought unresectable, may now be candidates for resection. Two-stage hepatectomy, repeat curative-intent hepatectomy, and even selected resection of extrahepatic metastases have further increased the number of patients who may be treated with curative intent. Multiple liver-directed therapies exist to treat unresectable, incurable patients with adequate survival benefit and morbidity rates

Comparing two corpus-based methods for extracting paraphrases to dictionary-based method

Paraphrase extraction plays an increasingly important role in language-related research and applications in areas such as information retrieval, question answering and automatic machine evaluation. Most of the existing methods extract paraphrases from different types of corpora by using syntactic-based approaches. Since a syntactic-based approach relies on the similarity of context to identify and capture paraphrases, other than paraphrases, other terms which tend to appear in a similar context such as loosely related terms and functionally similar yet unrelated terms tend to be extracted. Besides, different types of corpora suffer from different kinds of problems such as limited availability and domain biased. This paper presents a solely semantic-based paraphrase extraction model. This model collects paraphrases from multiple lexical resources and validates those paraphrases semantically in three ways; by computing domain similarity, definition similarity and word similarity. This model is benchmarked with two outstanding syntactic-based approaches. The experimental results from a manual evaluation show that the proposed model outperforms the benchmarks. The results indicate that a semantic-based approach should be applied in paraphrase extraction instead of a syntactic-based approach. The results further suggest that a hybrid of these two approaches should be applied if one targets strictly precise paraphrases

Characterization of a Partial cDNA for Lysyl Hydroxylase from Human Skin Fibroblasts; Lysyl Hydroxylase mRNAs Are Regulated Differently by Minoxidil Derivatives and Hydralazine

Lysyl hydroxylase (LH) is an essential enzyme in collagen biosynthesis that catalyzes the formation of hydroxylysine required for intermolecular crosslinking of collagen. We have isolated a partial (2.2-kb) cDNA for LH from human skin fibroblasts using PCR. DNA sequencing revealed 72% homology of the human coding sequence with the chick LH sequence at the nucleotide level and 76% homology predicted at the amino acid level. The LH cDNA hybridized strongly with two mRNA species of 2.4 and 3.4kb on Northern blots of normal fibroblast RNA. Administration of minoxidil decreased both mRNA species without affecting levels of the mRNAs for the β subunit of prolyl 4-hydroxylase (PH) or α1(I) collagen. Two derivatives of minoxidil (3' hydroxyminoxidil and 4' hydroxyminoxidil) produced similar decreases in LH mRNAs. In contrast hydralazine increased the mRNAs for LH in parallel with its previously reported effect on the mRNA for the β subunit of PH. This effect is accompanied by virtual elimination of the α1(I) collagen mRNAs. These results on the action of minoxidil and hydralazine at the pretranslational level correlate well with their previously reported effect on enzyme activity and collagen biosynthesis and indicate that changes in steady-state mRNA levels can account directly for changes at the protein level. Moreover, the unique action of minoxidil in specifically decreasing LH mRNAs contrasts with the less specific stimulatory effects of hydralazine and suggests that these pharmaceuticals arc regulating expression of LH at a pretranslational level by different mechanisms