2,804 research outputs found

    Experimental investigation of insolation-driven dust ejection from Mars’ CO2 ice caps

    Get PDF
    Mars’ polar caps are – depending on hemisphere and season - partially or totally covered with CO2 ice. Icy surfaces such as the polar caps of Mars behave differently from surfaces covered with rock and soil when they are irradiated by solar light. The latter absorb and reflect incoming solar radiation within a thin layer beneath the surface. In contrast, ices are partially transparent in the visible spectral range and opaque in the infrared. Due to this fact, the solar radiation can penetrate to a certain depth and raise the temperature of the ice or dust below the surface. This may play an important role in the energy balance of icy surfaces in the solar system, as already noted in previous investigations. We investigated the temperature profiles inside CO2 ice samples including a dust layer under Martian conditions. We have been able to trigger dust eruptions, but also demonstrated that these require a very narrow range of temperature and ambient pressure. We discuss possible implications for the understanding of phenomena such as arachneiform patterns or fan shaped deposits as observed in Mars’ southern polar region

    Fair Division

    Get PDF
    Wills and inheritances have traditionally been a cause of much discord in families. Which is why, when Mr. Jagirdar drew up his will, he invited his friend, the mathematician Mr. Z to meet him at a popular coffee shop and sought his help! You see, the problem was that he wanted to bequeath his triangular plot of land (shown in Fig. 1), bordered on three sides by roads, to his sons, and he wanted to divide the property so that both sons received equal land area and equal access to the road

    APC-AREA, perimeter and congruency

    Get PDF
    We continue our Low Floor High Ceiling series in which an activity is chosen – it starts by assigning simple age-appropriate tasks which can be attempted by all the students in the classroom. The complexity of the tasks builds up as the activity proceeds so that students are pushed to their limits as they attempt their work. There is enough work for all, but as the level gets higher, fewer students are able to complete the tasks. The point, however, is that all students are engaged and all of them are able to accomplish at least a part of the whole task

    Investigating the reliability and validity of the Dutch versions of the illness management and recovery scales among clients with mental disorders

    Get PDF
    Background: The Illness Management and Recovery scales (IMRS) can measure the progress of clients’ illness self-management and recovery. Previous studies have examined the psychometric properties of the IMRS. Aims: This study examined the reliability and validity of the Dutch version of the IMRS. Method: Clients (n = 111) and clinicians (n = 40) completed the client and clinician versions of the IMRS, respectively. The scales were administered again 2 weeks later to assess stability over time. Validity was assessed with the Utrecht Coping List (UCL), Dutch Empowerment Scale (DES), and Brief Symptom Inventory (BSI). Results: The client and clinician versions of the IMRS had moderate internal reliability, with α = 0.69 and 0.71, respectively. The scales showed strong test–retest reliability, r = 0.79, for the client version and r = 0.86 for the clinician version. Correlations between client and clinician versions ranged from r = 0.37 to 0.69 for the total and subscales. We also found relationships in expected directions between the client IMRS and UCL, DES and BSI, which supports validity of the Dutch version of the IMRS. Conclusions: The Dutch version of the IMRS demonstrated good reliability and validity. The IMRS could be useful for Dutch-speaking programs interested in evaluating client progress on illness self-management and recovery

    Histologic, immunohistochemical, and electron microscopic characterization of a malignant iridophoroma in a dwarf bearded dragon (Pogona henrylawsoni)

    Get PDF
    A dwarf bearded dragon (Pogona henrylawsoni) was presented with a whitish subcutaneous mandibular mass and multiple nodules in the oral mucosa, heart, liver, kidney, intestine and visceral fat. Histologically, the tumor consisted of densely packed spindle-shaped cells with brownish intracytoplasmic pigment that exhibited white-bluish birefringence with polarized light. Immunohistochemical staining was negative for S-100 and weakly positive with Melan A. Negative contrast electron microscopic examination revealed cytoplasmic irregular, oblong empty spaces, laminated and often arranged into short stacks, compatible with reflecting platelet profiles typically seen in iridophores. However, in unstained ultrathin sections, electron dense crystalline material was present which filled the empty spaces described for stained sections before. Based on histology, immunohistochemistry and biological behavior, a malignant iridophoroma was diagnosed. To the authors’ knowledge, iridophoromas in lizards have not been characterized before by using electronic microscopy. Moreover, this is the first description of an iridophoroma in a dwarf bearded dragon
    • …
    corecore