The Organization Of The Maize Photosystem Ii Light-harvesting Apparatus Under Normal And Chilling Conditions

The maize light harvesting system is structurally and functionally perturbed by chilling stress, with alterations in fluorescence parameters and protein processing. The molecular basis for these changes was investigated through biochemical analysis of the photosystem II-associated light-harvesting complexes (LHC II) of maize mesophyll thylakoids.;LHC II complexes from thylakoids were separated into three populations by mildly-denaturing electrophoresis. LHC II-1 contains four polypeptides and is equivalent to the oligomeric LHC IIb complex of Thornber et al. (1988). A less abundant oligomeric band, LHC II-2, contains a subset of the LHC IIb polypeptides, along with the LHC IIa complex (CP 29). The LHC II-3 band contains the LHC IIa and LHC IIc complexes. The LHC IIa and LHC IIb polypeptides were identified by immunoblotting. The LHC II populations separated from PS II-enriched membranes are similar, but isolated LHC II particles generate three chlorophyll-protein bands, all derived from LHC IIb.;Interactions among LHC II complexes were investigated by protein cross-linking with 3,3{dollar}\sp\prime{dollar}-dithio-bis(propionic acid n-hydroxysuccinimide ester) (DSP), a cleavable cross-linker of 1.1 nm length. Cross-linking occurs between appressed thylakoids, as shown by resistance to unstacking following DSP treatments. DSP treatment gave cross-linking between the LHC IIa and LHC IIb complexes, among LHC IIb complexes, between the PS II core and LHC IIa/LHC IIb and between the PS I core and LHC I. Disruption of appression prior to DSP treatment eliminates the LHC IIa/LHC IIb and the LHC IIa/LHC IIb/PS II cross-linked products. Hence, specific linkages occur between the PS II related complexes of adjacent appressed thylakoid membranes. This organization may have functional implications.;The assembly of LHC IIb oligomers is disrupted by low light chilling stress. Three LHC IIb polypeptides are heavily labelled by light-induced phosphorylation of thylakoids. The pattern of LHC IIb phosphorylation is altered by low or high light chilling stress prior to thylakoid isolation; the effect is partially reversed by the presence of high ATP concentrations during phosphorylation. These changes provide biochemical background to disruption of LHC II function following chilling. The timing of chilling stress influences the degree of chill-induced changes

Kirigami Actuators

Thin elastic sheets bend easily and, if they are patterned with cuts, can deform in sophisticated ways. Here we show that carefully tuning the location and arrangement of cuts within thin sheets enables the design of mechanical actuators that scale down to atomically-thin 2D materials. We first show that by understanding the mechanics of a single, non-propagating crack in a sheet we can generate four fundamental forms of linear actuation: roll, pitch, yaw, and lift. Our analytical model shows that these deformations are only weakly dependent on thickness, which we confirm with experiments at centimeter scale objects and molecular dynamics simulations of graphene and MoS$_{2}$ nanoscale sheets. We show how the interactions between non-propagating cracks can enable either lift or rotation, and we use a combination of experiments, theory, continuum computational analysis, and molecular dynamics simulations to provide mechanistic insights into the geometric and topological design of kirigami actuators.Comment: Soft Matter, 201

Constraints on Mars Aphelion Cloud Belt Phase Function and Ice Crystal Geometries

This study constrains the lower bound of the scattering phase function of Martian water ice clouds (WICs) through the implementation of a new observation aboard the Mars Science Laboratory (MSL). The Phase Function Sky Survey (PFSS) was a multiple pointing all-sky observation taken with the navigation cameras (Navcam) aboard MSL. The PFSS was executed 35 times during the Aphelion Cloud Belt (ACB) season of Mars Year 34 over a solar longitude range of L_s=61.4{\deg}-156.5{\deg}. Twenty observations occurred in the morning hours between 06:00 and 09:30 LTST, and 15 runs occurred in the evening hours between 14:30 and 18:00 LTST, with an operationally required 2.5 hour gap on either side of local noon due the sun being located near zenith. The resultant WIC phase function was derived over an observed scattering angle range of 18.3{\deg} to 152.61{\deg}, normalized, and compared with 9 modeled phase functions: seven ice crystal habits and two Martian WIC phase functions currently being implemented in models. Through statistical chi-squared probability tests, the five most probable ice crystal geometries observed in the ACB WICs were aggregates, hexagonal solid columns, hollow columns, plates, and bullet rosettes with p-values greater than or equal to 0.60, 0.57,0.56,0.56, and 0.55, respectively. Droxtals and spheres had p-values of 0.35, and 0.2, making them less probable components of Martian WICs, but still statistically possible ones. Having a better understanding of the ice crystal habit and phase function of Martian water ice clouds directly benefits Martian climate models which currently assume spherical and cylindrical particles.Comment: Accepted Manuscript by Planetary and Space Scienc

A Comparison of the Strengths and Weaknesses of Small-Format Aerial Photography Platforms

The demand for small-format aerial photography continues to grow in large part due to the rapid adoption of unmanned aerial vehicles (UAVs). Prior to the explosion of UAV use, this kind of photography was collected using older technologies such as tethered kites and blimps. Due to the increased demand for aerial imagery, this article looks at four platforms commonly used to collect small-format aerial imagery: multi-rotor UAVs, fixed-wing UAVs, kites, and blimps. Practical use considerations are explored, including characteristics of flight and operation, atmospheric and site factors, imaging sensors and costs, and regulatory limitations. Each of the four categories of lifting platform have their strengths and limitations, and they often complement one another. UAVs tends to be more maneuverable and able to cover more ground, but they have limited flight times due to battery technology limitations. They also have clearly defined regulatory requirements for use, whereas the tethered platforms have very few legal restrictions on use. In some cases, a tethered platform may be the only legal option for gathering small-format aerial imagery at a location. There is no one perfect option that will fill all needs, but rather multiple solutions that are better suited to some situations than others. The ways in which some of these strengths and limitations may change in the future in regards to technology and regulations is also discussed

Referral for menstrual problems:cross sectional survey of symptoms, reasons for referral, and management

OBJECTIVES: To describe the menstrual experience of women referred for menstrual problems, in particular menorrhagia (excessive menstrual loss), and to assess associations with reasons for referral given by their general practitioners, the women's understanding of the reasons for their attendance at the hospital clinics, and clinic outcome. DESIGN: Questionnaire survey, with partial review of case notes after 8 months. SETTING: Three hospital gynaecology clinics in Glasgow and Edinburgh. PARTICIPANTS: 952 women completed the questionnaire, and the first 665 were reviewed. OUTCOME MEASURES: Reason for referral, women's reported menstrual problems and reason for clinic attendance, diagnosis, and treatment. RESULTS: Only 38% (95% confidence interval 34% to 41%) of women reported excessive menstrual loss as a severe problem. However 60% (57-63%) gave it as reason for attending a clinic, and 76% (73-79%) of general practitioners gave it as reason for referral. Reason for referral was significantly biased towards bleeding (McNemar odds ratio 4.01, 3.0 to 5.3, P<0.001) and against pain (0.54, 0.4 to 0.7, P<0.001). Dysfunctional uterine bleeding was diagnosed in 37% (31-42%) of the 259 women who gave as reason for attendance something other than bleeding. Women who were economically disadvantaged differed in prevalence of the main diagnoses and were more likely to fail to reattend. Hysterectomy was associated with referral for bleeding (relative risk 4.9, 1.6 to 15.6, P<0.001) but not with the patient stating bleeding as the reason for clinic attendance. CONCLUSIONS: Intolerance of the volume of their bleeding is not a key feature among women attending clinics for bleeding problems. Broad menstrual complaint tends to be reframed as excessive bleeding at referral and during management. This may result in women receiving inappropriate care. Conceptualisation and assessment of menorrhagia requires reconsideration

The effect of underwater massage during hot water immersion on acute cardiovascular and mood responses

Purpose: There is emerging evidence that demonstrates the health benefits of hot water immersion including improvements to cardiovascular health and reductions in stress and anxiety. Many commercially available hot tubs offer underwater massage systems which purport to enhance many benefits of hot water immersion, however, these claims have yet to be studied. Methods: Twenty participants (4 females) completed three, 30-minute sessions of hot-water immersion (beginning at 39°C) in a crossover randomized design: with air massage (Air Jet), water massage (Hydro Jet) or no massage (Control). Cardiovascular responses comprising; heart rate, blood pressure and superficial femoral artery blood flow and shear rate were measured. State trait anxiety, basic affect, and salivary cortisol were recorded before and after each trial. Data were analysed using a mixed effects model.Results: Post immersion, heart rate increased (Δ31bpm, P &lt; 0.001, d = 1.38), mean arterial blood pressure decreased (Δ16 mmHg, P&lt;0.001, d = −0.66), with no difference between conditions. Blood flow and mean shear rate increased following immersion (P &lt; 0.001, Δ362 ml/min, d = 1.20 and Δ108 s−1, d = 1.00), but these increases were blunted in the Air Jet condition (P &lt; 0.001,Δ171 ml/min, d = 0.43 and Δ52 s−1, d = 0.52). Anxiety and salivary cortisol were reduced (P = 0.003, d = −0.20, P = 0.014, d = −0.11), but did not vary between conditions. Enjoyment did not vary between conditions.Conclusion: These data demonstrate positive acute responses to hot water immersion on markers of cardiovascular function, anxiety, and stress. There was no additional benefit of water-based massage, while air-basedmassage blunted some positive vascular responses due to lower heat conservation of the water. <br/

Inter-annual and seasonal trends in cetacean distribution, density and abundance off southern California

The article of record as published may be located at https://doi.org/10.1016/j.dsr2.2014.10.008Funded by Naval Postgraduate SchoolTrends in cetacean density and distribution off southern California were assessed through visual line- transect surveys during thirty-seven California Cooperative Oceanic Fisheries Investigations (CalCOFI) cruises from July 2004–November 2013. From sightings of the six most commonly encountered cetacean species, seasonal, annual and overall density estimates were calculated. Blue whales (Balaenoptera musculus), fin whales (Balaenoptera physalus) and humpback whales (Megaptera novaeangliae) were the most frequently sighted baleen whales with overall densities of 0.91/1000 km2 (CV 1⁄4 0.27), 2.73/ 1000 km2 (CV 1⁄4 0.19), and 1.17/1000 km2 (CV 1⁄4 0.21) respectively. Species specific density estimates, stratified by cruise, were analyzed using a generalized additive model to estimate long-term trends and correct for seasonal imbalances. Variances were estimated using a non-parametric bootstrap with one day of effort as the sampling unit. Blue whales were primarily observed during summer and fall while fin and humpback whales were observed year-round with peaks in density during summer and spring respectively. Short-beaked common dolphins (Delphinus delphis), Pacific white-sided dolphins (Lagen- orhynchus obliquidens) and Dall’s porpoise (Phocoenoidesdalli) were the most frequently encountered small cetaceans with overall densities of 705.83/1000 km2 (CV1⁄40.22), 51.98/1000 km2 (CV1⁄40.27), and 21.37/1000 km2 (CV 1⁄4 0.19) respectively. Seasonally, short-beaked common dolphins were most abun- dant in winter whereas Pacific white-sided dolphins and Dall’s porpoise were most abundant during spring. There were no significant long-term changes in blue whale, fin whale, humpback whale, short- beaked common dolphin or Dall’s porpoise densities while Pacific white-sided dolphins exhibited a significant decrease in density across the ten-year study. The results from this study were fundamentally consistent with earlier studies, but provide greater temporal and seasonal resolution.Funding was provided by the Chief of Naval Operations Environmental Readiness Division, the United States Navy’s Pacific Fleet, the Naval Postgraduate School Grant #N00244-11-1-027, and the Naval Facilities Engineering Command Living Marine Resources Pro- gramFunding was provided by the Chief of Naval Operations Environmental Readiness Division, the United States Navy’s Pacific Fleet, the Naval Postgraduate School Grant #N00244-11-1-027, and the Naval Facilities Engineering Command Living Marine Resources Pro- gra