On localized vegetation patterns, fairy circles and localized patches in arid landscapes

We investigate the formation of localized structures with a varying width in one and two-dimensional systems. The mechanism of stabilization is attributed to strong nonlocal coupling mediated by a Lorentzian type of Kernel. We show that, in addition to stable dips found recently [see, e.g., C. Fernandez-Oto, M. G. Clerc, D. Escaff, and M. Tlidi, Phys. Rev. Lett. {\bf{110}}, 174101 (2013)], exist stable localized peaks which appear as a result of strong nonlocal coupling, i.e. mediated by a coupling that decays with the distance slower than an exponential. We applied this mechanism to arid ecosystems by considering a prototype model of a Nagumo type. In one-dimension, we study the front that connects the stable uniformly vegetated state with the bare one under the effect of strong nonlocal coupling. We show that strong nonlocal coupling stabilizes both---dip and peak---localized structures. We show analytically and numerically that the width of localized dip, which we interpret as fairy circle, increases strongly with the aridity parameter. This prediction is in agreement with filed observations. In addition, we predict that the width of localized patch decreases with the degree of aridity. Numerical results are in close agreement with analytical predictions

Plant clonal morphologies and spatial patterns as self-organized responses to resource-limited environments

We propose here to interpret and model peculiar plant morphologies (cushions, tussocks) observed in the Andean altiplano as localized structures. Such structures resulting in a patchy, aperiodic aspect of the vegetation cover are hypothesized to self-organize thanks to the interplay between facilitation and competition processes occurring at the scale of basic plant components biologically referred to as 'ramets'. (Ramets are often of clonal origin.) To verify this interpretation, we applied a simple, fairly generic model (one integro-differential equation) emphasizing via Gaussian kernels non-local facilitative and competitive feedbacks of the vegetation biomass density on its own dynamics. We show that under realistic assumptions and parameter values relating to ramet scale, the model can reproduce some macroscopic features of the observed systems of patches and predict values for the inter-patch distance that match the distances encountered in the reference area (Sajama National Park in Bolivia). Prediction of the model can be confronted in the future to data on vegetation patterns along environmental gradients as to anticipate the possible effect of global change on those vegetation systems experiencing constraining environmental conditions.Comment: 14 pages, 6figure

Potensi Individu Amblyseius Deleoni Et Denmark Sebagai Predator Hama Tungau Panonychus Citri McGregor Pada Tanaman Jeruk

. Setyobudi, L., M. Istianto, and O. Endarto. 2007. Individual Potency of Amblyseius deleoni et Denmark as Predator of Panonychus citri McGregor on Citrus. Panonychus citri is one of the most economically important citrus pests in Indonesia. Controlling to this pest population is needed to suppress the crop losses of citrus production. One of the technologies to control mite population is by applying natural enemies. The objective of this research was to evaluate the individual potency of A. deleoni to prey P. citri. The research was arranged in a completely randomized design with 6 treatments and 10 replications This research was conducted from August 1999 to January 2000 in Laboratory of Entomology of Indonesian Citrus and Subtropic Fruit Research Institute Tlekung. The treatments were A. deleoni put in the several stages of P. citri lifecycle i.e. (1) eggs, (2) larva, (3) nymph, (4) adult, (5) mixed stages of P. citri, and (6) pollens of papaya. The results showed that A. deleoni had a potency to prey P. citri. During the treatments, individual of A. deleoni was able to prey 1.80-2.16 eggs/day, 1.08-2.22 larvae/day, 0.70-1.52 nymphs/day, 0.47-1.08 adults/day, 1.15-2.93 mixed stages of P. citri/day. The treatments tended not to have significant influence to longevity of A. deleoni. The largest number of eggs and first generation of A. deleoni found in the treatment of eggs of P. citri as a prey i.e. 14.40 and 11.52 respectively. This results gives an alternative predator that can be used to control the population of P. citri on citrus

Measurement of renin in both renal veins: its use in diagnosis of renovascular hypertension

THE RECENT development of a simple reliable method for measuring plasma renin activity, together with the availability of a safe procedure for obtaining samples of blood from both renal veins, has prompted us to assess the utility of such measurements in the diagnosis of surgically correctable renovascular hypertension. Previous studies of this type have been reported by McPhaul,1 Fitz,2 Kirkendall,3 and Ueda,4 and their associates. A series of 22 patients, diagnosed by conventional measures as having renovascular hypertension, were subjected to operative treatment. Proof of the diagnosis was considered to be established if there was unquestionable improvement in blood pressure after corrective surgery. This is a report of the measurements of renin activity in blood plasma specimens obtained from both renal veins preoperatively and, whenever possible, postoperatively. In addition, plasma renin activity in effluent blood from both kidneys was measured in 13 patients with "essential" hypertension, who were not subjecte

Proportion and Factors Associated with Zinc Deficiency in Acute Diarrhea Patients

Background: Zinc may affect the intestinal immune response. No data has been available on zinc deficiency in adult patients with diarrhea, especially for Indonesian population. Zinc metabolism, etiologies, pathogenesis and clinical course of diarrhea may have various effects on zinc concentration in different population. This study aimed to determine the proportion of zinc deficiency in patients with acute diarrhea, including its associated factors. Method: A cross-sectional study was conducted in patients with acute diarrhea at outpatient clinics and emergency wards of four hospitals between August 2010 and March 2011. A serum zinc concentration of < 10.7 µmol/L was set as cut-off value for zinc deficiency. Data was analyzed by using Chi-square test. Results: There were 101 subjects, 54.5% were female, the median age was 26 years, median duration of acute diarrhea was 5 days, and the median frequency was 6 times/day. About 95% patients had nutritional status of subjective global assessment (SGA) A and the mean value of body mass index was 19.3 ± 0.70 kg/m2. Approximately 88.1% patients had severe infective diarrhea based on hydration status. About 69.3% patients were zinc deficient with the mean serum zinc concentration of 9.26 ± 2.95 µ mol/L. We found a significant correlation between the severity of diarrhea and zinc deficiency in patients with acute diarrhea. Conclusion: The proportion of zinc deficiency in acute diarrhea patients was quite large although the mean serum zinc level was still below the National Health and Nutrition Examination Survey (NHANES) reference value. The severity of diarrhea has been proven to be significant that affects zinc deficiency in acute diarrhea patients

Proximity effects and Andreev reflection in mesoscopic SNS junction with perfect NS interfaces

Low temperature transport measurements on superconducting film - normal metal wire - superconducting film (SNS) junctions fabricated on the basis of 6 nm thick superconducting polycrystalline PtSi films are reported. The structures with the normal metal wires of two different lengths L=1.5 $\mu$m and L=6$\mu$m and the same widths W=0.3$\mu$m are studied. Zero bias resistance dip related to pair current proximity effect is observed for all junctions whereas the subharmonic energy gap structure originating from phase coherent multiple Andreev reflections have occurs only in the SNS junctions with short wires.Comment: ReVTex, 4 pages, 4 eps figures include

Transcript of The Dory Derby Accident

This story is an excerpt from a longer interview that was collected as part of the Launching through the Surf: The Dory Fleet of Pacific City project. In this story, Don Grotjohn recounts an accident that occurred during a Dory Derby competition

Separately contacted edge states: A new spectroscopic tool for the investigation of the quantum Hall effect

Using an innovative combination of a quasi-Corbino sample geometry and the cross-gate technique, we have developed a method that enables us to separately contact single edge channels in the quantum Hall regime and investigate equilibration among them. Performing 4-point resistance measurements, we directly obtain information on the energetic and geometric structure of the edge region and the equilibration-length for current transport across the Landau- as well as the spin-gap. Based on an almost free choice in the number of participating edge channels and their interaction-length a systematic investigation of the parameter-space becomes possible.Comment: 8 pages, 7 figure

Colitis Tuberculosis

Tuberculosis (TB) is a significant public health problem worldwide. Indonesia is a country with the third highest prevalence of TB in the world after China and India. TB infection can attack all organs of the human body. TB in digestive system is one of the extrapulmonary TB manifestations and comprises of 3- 16% of all extrapulmonary TB cases. This type of TB may affect digestive system, peritoneum, mesentery lymphatic glands, liver, and spleen. Digestive system is affected in 66-75% of patients with abdominal TB. The ileocaecal region is most commonly affected. The manifestation of abdominal TB is not specific. Precise diagnostic approach and supporting results are needed to determine final diagnosis. However, there is no single examination adequate enough to diagnose abdominal TB. If the diagnosis can be established early, this disease could then be managed with conventional anti-TB drugs. Treatment for both 6-9 months period and 18-24 months period has been proven effective in management of extrapulmonary TB. In countries with high abdominal TB prevalence, initiation of anti-TB therapy is allowed if there are the clinical features present. Diagnosis can be determined when the patient has therapeutic response against the the anti-TB treatment