Dust Devil Tracks

Dust devils that leave dark- or light-toned tracks are common on Mars and they can also be found on the Earth’s surface. Dust devil tracks (hereinafter DDTs) are ephemeral surface features with mostly sub-annual lifetimes. Regarding their size, DDT widths can range between ∼1 m and ∼1 km, depending on the diameter of dust devil that created the track, and DDT lengths range from a few tens of meters to several kilometers, limited by the duration and horizontal ground speed of dust devils. DDTs can be classified into three main types based on their morphology and albedo in contrast to their surroundings; all are found on both planets: (a) dark continuous DDTs, (b) dark cycloidal DDTs, and (c) bright DDTs. Dark continuous DDTs are the most common type on Mars. They are characterized by their relatively homogenous and continuous low albedo surface tracks. Based on terrestrial and martian in situ studies, these DDTs most likely form when surficial dust layers are removed to expose larger-grained substrate material (coarse sands of ≥500 μm in diameter). The exposure of larger-grained materials changes the photometric properties of the surface; hence leading to lower albedo tracks because grain size is photometrically inversely proportional to the surface reflectance. However, although not observed so far, compositional differences (i.e., color differences) might also lead to albedo contrasts when dust is removed to expose substrate materials with mineralogical differences. For dark continuous DDTs, albedo drop measurements are around 2.5 % in the wavelength range of 550–850 nm on Mars and around 0.5 % in the wavelength range from 300–1100 nm on Earth. The removal of an equivalent layer thickness around 1 μm is sufficient for the formation of visible dark continuous DDTs on Mars and Earth. The next type of DDTs, dark cycloidal DDTs, are characterized by their low albedo pattern of overlapping scallops. Terrestrial in situ studies imply that they are formed when sand-sized material that is eroded from the outer vortex area of a dust devil is redeposited in annular patterns in the central vortex region. This type of DDT can also be found in on Mars in orbital image data, and although in situ studies are lacking, terrestrial analog studies, laboratory work, and numerical modeling suggest they have the same formation mechanism as those on Earth. Finally, bright DDTs are characterized by their continuous track pattern and high albedo compared to their undisturbed surroundings. They are found on both planets, but to date they have only been analyzed in situ on Earth. Here, the destruction of aggregates of dust, silt and sand by dust devils leads to smooth surfaces in contrast to the undisturbed rough surfaces surrounding the track. The resulting change in photometric properties occurs because the smoother surfaces have a higher reflectance compared to the surrounding rough surface, leading to bright DDTs. On Mars, the destruction of surficial dust-aggregates may also lead to bright DDTs. However, higher reflective surfaces may be produced by other formation mechanisms, such as dust compaction by passing dust devils, as this may also cause changes in photometric properties. On Mars, DDTs in general are found at all elevations and on a global scale, except on the permanent polar caps. DDT maximum areal densities occur during spring and summer in both hemispheres produced by an increase in dust devil activity caused by maximum insolation. Regionally, dust devil densities vary spatially likely controlled by changes in dust cover thicknesses and substrate materials. This variability makes it difficult to infer dust devil activity from DDT frequencies. Furthermore, only a fraction of dust devils leave tracks. However, DDTs can be used as proxies for dust devil lifetimes and wind directions and speeds, and they can also be used to predict lander or rover solar panel clearing events. Overall, the high DDT frequency in many areas on Mars leads to drastic albedo changes that affect large-scale weather patterns

A Historiometric Examination of Machiavellianism and a New Taxonomy of Leadership

Although researchers have extensively examined the relationship between charismatic leadership and Machiavellianism (Deluga, 2001; Gardner & Avolio, 1995; House & Howell, 1992), there has been a lack of investigation of Machiavellianism in relation to alternative forms of outstanding leadership. Thus, the purpose of this investigation was to examine the relationship between Machiavellianism and a new taxonomy of outstanding leadership comprised of charismatic, ideological, and pragmatic leaders. Using an historiometric approach, raters assessed Machiavellianism via the communications of 120 outstanding leaders in organizations across the domains of business, political, military, and religious institutions. Academic biographies were used to assess twelve general performance measures as well as twelve general controls and five communication specific controls. The results indicated that differing levels of Machiavellianism is evidenced across the differing leader types as well as differing leader orientation. Additionally, Machiavellianism appears negatively related to performance, though less so when type and orientation are taken into account.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Evaluation of an inflammation-based prognostic score (GPS) in patients undergoing resection for colon and rectal cancer

<p><b>Background/aims</b></p> <p>The aim of the study was to examine the value of the combination of an elevated C-reactive protein and hypoalbuminaemia (GPS) in predicting cancer-specific survival after resection for colon and rectal cancer.</p> <p><b>Materials and methods</b></p> <p>The GPS was constructed as follows: Patients with both an elevated C-reactive protein (>10 mg/l) and hypoalbuminaemia (<35 g/l) were allocated a score of 2. Patients in whom only one or none of these biochemical abnormalities was present were allocated a score of 1 or 0, respectively.</p> <p><b>Results</b></p> <p>A GPS of 1 (n = 109) was mainly due to an elevated C-reactive protein concentration and the remainder due to hypoalbuminaemia. In those patients with a GPS of 1 due to hypoalbuminaemia (n  = 16), the 3-year overall survival rate was 94% compared with 62% in those patients with a GPS of 1 due to an elevated C-reactive protein concentration (n = 93, p = 0.0094). Therefore, the GPS was modified such that patients with hypoalbuminaemia were assigned a score of 0 in the absence of an elevated C-reactive protein. On univariate analysis of those patients with colon and rectal cancer, the modified GPS (p< 0.0001) was significantly associated with overall and cancer specific survival. On univariate survival analysis of those patients with Dukes B colon and rectal cancer, the modified GPS (p< 0.01) was significantly associated with overall and cancer specific survival.</p> <p><b>Conclusion</b></p> <p>The results of the present study indicate that the GPS, before surgery, predicts overall and cancer-specific survival after resection of colon and rectal cancer.</p&gt

Tumor size is associated with the systemic inflammatory response but not survival in patients with primary operable colorectal cancer

<p><b>AIM:</b> To examine the relationship between tumor diameter, C-reactive protein concentrations and survival in patients undergoing surgery for colorectal cancer.</p> <p><b>METHOD:</b> Tumor diameter and pathological characteristics of the resected specimen were assessed in 227 patients. Circulating concentrations of C-reactive protein were measured prior to surgery.</p> <p><b>RESULTS:</b> Ninety-six patients had an elevated C-reactive protein concentration (>10 mg/L) prior to surgery. Tumor size was associated with an elevated C-reactive protein concentration (P < 0.001). C-reactive protein concentrations (P < 0.001) were associated with poorer cancer-specific survival.</p> <p><b>CONCLUSION:</b> Prior to surgery, the maximal tumor diameter is associated with an elevated preoperative C-reactive protein concentration but not survival in patients with primary operable colorectal cancer.</p&gt

Preoperative but not postoperative systemic inflammatory response correlates with survival in colorectal cancer

<p><b>Background:</b></p> <p>The aim of the present study was to evaluate the relationship between the preoperative and postoperative systemic inflammatory response and survival in patients undergoing potentially curative resection for colorectal cancer.</p> <p><b>Methods:</b></p> <p>One hundred and eighty patients with colorectal cancer were studied. Circulating concentrations of C-reactive protein (CRP) were measured before surgery and in the immediate postoperative period.</p> <p><b>Results:</b></p> <p>The peak in CRP concentration occurred on day 2 (P < 0·001). During the course of the study 59 patients died, 30 from cancer and 29 from intercurrent disease. Day 2 CRP concentrations were dichotomized. In univariable analysis, advanced tumour node metastasis stage (P = 0·002), a raised preoperative CRP level (P < 0·001) and the presence of hypoalbuminaemia (P = 0·043) were associated with poorer cancer-specific survival.</p> <p><b>Conclusion:</b></p> <p>Preoperative but not postoperative CRP concentrations are associated with poor tumour-specific survival in patients undergoing potentially curative resection for colorectal cancer.</p&gt