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Sample records for analog som230 pasireotide

  1. Pasireotide (SOM230) is Effective for the Treatment of Pancreatic Neuroendocrine Tumors (PNETs) in a Multiple Endocrine Neoplasia Type 1 (MEN1) Conditional Knockout Mouse Model

    PubMed Central

    Quinn, Thomas J.; Yuan, Ziqiang; Adem, Asha; Geha, Rula; Vrikshajanani, Chakravarthy; Koba, Wade; Fine, Eugene; Hughes, David T.; Schmid, Herbert; Libutti, Steven K.

    2013-01-01

    Background Pasireotide (SOM230), a long acting somatostatin analogue (LAR) has improved agonist activity at somatostatin receptors. We tested the effect of SOM230 on insulin secretion, glucose levels, tumor growth, and survival using an MEN1 transgenic mouse model. Methods Eight 12 month-old conditional Men1 knockout mice with insulinoma were assessed. The treatment (N=4) and control groups (N=4) received monthly subcutaneous injections of SOM230 or PBS. Serum insulin and glucose levels were determined by ELISA and enzymatic colorimetric assay, respectively. Tumor activity, growth, and apoptosis were determined by microPET/CT scan and histological analysis. Results On day 7, there was a significant decrease in serum insulin from 1.060μg/L±0.2769 to 0.3653μg/L±0.1676 (p=0.0128) and a significant increase in serum glucose from 4.246mmol/L±0.4536 to 7.122mmol/L±1.058 (p=0.0075) in the treatment group, but no change in the control group. Tumor size was significantly smaller in the treatment group (2098μm2±388) compared with the control group (7067μm2±955) (p=0.0024). Furthermore, apoptosis was significantly increased in the treatment group (6.92%±1.23) compared with the control group (0.299%±0.103). Conclusions SOM230 demonstrates antisecretory, antiproliferative, and proapoptotic activity in our MEN1 model of insulinoma. Further studies of the effects of SOM230 in PNET patients with MEN1 mutations are warranted. PMID:23102680

  2. Osilodrostat (LCI699), a potent 11β-hydroxylase inhibitor, administered in combination with the multireceptor-targeted somatostatin analog pasireotide: A 13-week study in rats

    SciTech Connect

    Li, Li; Vashisht, Kapil; Boisclair, Julie; Li, Wenkui; Lin, Tsu-han; Schmid, Herbert A.; Kluwe, William; Schoenfeld, Heidi; Hoffmann, Peter

    2015-08-01

    The somatostatin analog pasireotide and the 11β-hydroxylase inhibitor osilodrostat (LCI699) reduce cortisol levels by distinct mechanisms of action. There exists a scientific rationale to investigate the clinical efficacy of these two agents in combination. This manuscript reports the results of a toxicology study in rats, evaluating different doses of osilodrostat and pasireotide alone and in combination. Sixty male and 60 female rats were randomized into single-sex groups to receive daily doses of pasireotide (0.3 mg/kg/day, subcutaneously), osilodrostat (20 mg/kg/day, orally), osilodrostat/pasireotide in combination (low dose, 1.5/0.03 mg/kg/day; mid-dose, 5/0.1 mg/kg/day; or high dose, 20/0.3 mg/kg/day), or vehicle for 13 weeks. Mean body-weight gains from baseline to Week 13 were significantly lower in the pasireotide-alone and combined-treatment groups compared to controls, and were significantly higher in female rats receiving osilodrostat monotherapy. Osilodrostat and pasireotide monotherapies were associated with significant changes in the histology and mean weights of the pituitary and adrenal glands, liver, and ovary/oviduct. Osilodrostat alone was associated with adrenocortical hypertrophy and hepatocellular hypertrophy. In combination, osilodrostat/pasireotide did not exacerbate any target organ changes and ameliorated the liver and adrenal gland changes observed with monotherapy. C{sub max} and AUC{sub 0–24h} of osilodrostat and pasireotide increased in an approximately dose-proportional manner. In conclusion, the pasireotide and osilodrostat combination did not exacerbate changes in target organ weight or toxicity compared with either monotherapy, and had an acceptable safety profile; addition of pasireotide to the osilodrostat regimen may attenuate potential adrenal gland hyperactivation and hepatocellular hypertrophy, which are potential side effects of osilodrostat monotherapy. - Highlights: • We examined the target organ toxicity of SOM230

  3. Pharmacokinetics, pharmacodynamics, and safety of pasireotide LAR in patients with acromegaly: a randomized, multicenter, open-label, phase I study.

    PubMed

    Petersenn, Stephan; Bollerslev, Jens; Arafat, Ayman M; Schopohl, Jochen; Serri, Omar; Katznelson, Laurence; Lasher, Janet; Hughes, Gareth; Hu, Ke; Shen, George; Reséndiz, Karina Hermosillo; Giannone, Vanessa; Beckers, Albert

    2014-11-01

    Pasireotide (SOM230), a multireceptor-targeted somatostatin analogue, has exhibited favorable safety/tolerability in several clinical studies. A long-acting-release (LAR) formulation of pasireotide may offer advantages over the subcutaneous formulation. This randomized, open-label, Phase I study evaluated the safety, PK, and PD of pasireotide LAR 20, 40, or 60 mg/month in patients with acromegaly. Safety assessments and blood samples for PK and PD were taken at designated time points. Thirty-five patients were randomized and completed the study. Steady-state pasireotide concentrations were achieved following three monthly injections. Trough pasireotide concentrations (ng/mL) 28 days after each injection were: 2.48, 4.16, and 3.10 (20 mg group); 6.42, 6.62, and 7.12 (40 mg group); and 9.51, 11.7, and 13.0 (60 mg group). At study end, 51% and 57% of patients achieved GH levels ≤2.5 μg/L and IGF-1 levels below ULN, respectively. Compared with baseline, fasting blood glucose and HbA1c levels increased, whereas fasting blood insulin levels decreased. Acromegaly symptoms were generally improved. Adverse events were mostly gastrointestinal and mild/moderate. Pasireotide LAR was generally well tolerated. Steady-state PK was achieved after three monthly doses; exposures were approximately dose proportional. Control of GH, IGF-1, and symptoms improved, suggesting that pasireotide LAR may be an effective treatment for acromegaly.

  4. Pasireotide in Acromegaly: A Review.

    PubMed

    McKeage, Kate

    2015-06-01

    Pasireotide (Signifor(®), Signifor(®) LAR) is a somatostatin analogue recently approved for the treatment of acromegaly. Unlike the first-generation agents, octreotide and lanreotide, which bind preferentially to somatostatin receptor (SSTR)-2, pasireotide binds to multiple SSTRs. This article reviews the clinical use and summarizes the pharmacological properties of intramuscular pasireotide in the treatment of acromegaly. The efficacy of pasireotide 40 mg every 28 days was superior to that of intramuscular octreotide 20 mg every 28 days with regard to biochemical control in a 12-month, phase III trial in medically naive patients. Similarly, in a 6-month, phase III trial in patients with acromegaly inadequately controlled with somatostatin analogues for at least 6 months, the efficacy of pasireotide 40 or 60 mg was superior to that of continued octreotide 30 mg or lanreotide autogel 120 mg (each drug was administered once every 28 days) with regard to biochemical control. The tolerability profile of intramuscular pasireotide is generally similar to that of first-generation agents, except for a higher incidence of hyperglycaemia-related adverse events with pasireotide. In clinical trials, the risk of developing pasireotide-associated hyperglycaemia was numerically greater in patients categorized as diabetic or prediabetic at baseline than in those with normal glucose tolerance. Careful monitoring of glycaemic status is required prior to and during pasireotide treatment and antidiabetic therapy should be commenced as indicated. Thus, in the treatment of acromegaly, pasireotide may be a more effective somatostatin analogue than other approved agents of the same class; however, the increased risk of hyperglycaemia needs to be considered and proactively managed.

  5. Lung volume quantified by MRI reflects extracellular-matrix deposition and altered pulmonary function in bleomycin models of fibrosis: effects of SOM230.

    PubMed

    Egger, Christine; Gérard, Christelle; Vidotto, Nella; Accart, Nathalie; Cannet, Catherine; Dunbar, Andrew; Tigani, Bruno; Piaia, Alessandro; Jarai, Gabor; Jarman, Elizabeth; Schmid, Herbert A; Beckmann, Nicolau

    2014-06-15

    Idiopathic pulmonary fibrosis is a progressive and lethal disease, characterized by loss of lung elasticity and alveolar surface area, secondary to alveolar epithelial cell injury, reactive inflammation, proliferation of fibroblasts, and deposition of extracellular matrix. The effects of oropharyngeal aspiration of bleomycin in Sprague-Dawley rats and C57BL/6 mice, as well as of intratracheal administration of ovalbumin to actively sensitized Brown Norway rats on total lung volume as assessed noninvasively by magnetic resonance imaging (MRI) were investigated here. Lung injury and volume were quantified by using nongated or respiratory-gated MRI acquisitions [ultrashort echo time (UTE) or gradient-echo techniques]. Lung function of bleomycin-challenged rats was examined additionally using a flexiVent system. Postmortem analyses included histology of collagen and hydroxyproline assays. Bleomycin induced an increase of MRI-assessed total lung volume, lung dry and wet weights, and hydroxyproline content as well as collagen amount. In bleomycin-treated rats, gated MRI showed an increased volume of the lung in the inspiratory and expiratory phases of the respiratory cycle and a temporary decrease of tidal volume. Decreased dynamic lung compliance was found in bleomycin-challenged rats. Bleomycin-induced increase of MRI-detected lung volume was consistent with tissue deposition during fibrotic processes resulting in decreased lung elasticity, whereas influences by edema or emphysema could be excluded. In ovalbumin-challenged rats, total lung volume quantified by MRI remained unchanged. The somatostatin analog, SOM230, was shown to have therapeutic effects on established bleomycin-induced fibrosis in rats. This work suggests MRI-detected total lung volume as readout for tissue-deposition in small rodent bleomycin models of pulmonary fibrosis.

  6. Phase II clinical trial of pasireotide long-acting repeatable in patients with metastatic neuroendocrine tumors

    PubMed Central

    Cives, M; Kunz, P L; Morse, B; Coppola, D; Schell, M J; Campos, T; Nguyen, P T; Nandoskar, P; Khandelwal, V; Strosberg, J R

    2015-01-01

    Pasireotide long-acting repeatable (LAR) is a novel somatostatin analog (SSA) with avid binding affinity to somatostatin receptor subtypes 1, 2, 3 (SSTR1,2,3) and 5 (SSTR5). Results from preclinical studies indicate that pasireotide can inhibit neuroendocrine tumor (NET) growth more robustly than octreotide in vitro. This open-label, phase II study assessed the clinical activity of pasireotide in treatment-naïve patients with metastatic grade 1 or 2 NETs. Patients with metastatic pancreatic and extra-pancreatic NETs were treated with pasireotide LAR (60 mg every 4 weeks). Previous systemic therapy, including octreotide and lanreotide, was not permitted. Tumor assessments were performed every 3 months using Response Evaluation Criteria in Solid Tumors (RECIST) criteria. The primary endpoint was progression-free survival (PFS). The secondary endpoints included overall survival (OS), overall radiographic response rate (ORR), and safety. Twenty-nine patients were treated with pasireotide LAR (60 mg every 4 weeks) and 28 were evaluable for response. The median PFS was 11 months. The most favorable effect was observed in patients with low hepatic tumor burden, normal baseline chromogranin A, and high tumoral SSTR5 expression. Median OS has not been reached; the 30-month OS rate was 70%. The best radiographic response was partial response in one patient (4%), stable disease in 17 patients (60%), and progressive disease in ten patients (36%). Although grade 3/4 toxicities were rare, pasireotide LAR treatment was associated with a 79% rate of hyperglycemia including 14% grade 3 hyperglycemia. Although pasireotide appears to be an effective antiproliferative agent in the treatment of advanced NETs, the high incidence of hyperglycemia raises concerns regarding its suitability as a first-line systemic agent in unselected patients. SSTR5 expression is a potentially predictive biomarker for response. PMID:25376618

  7. Serial follow-up of presurgical treatment using pasireotide long-acting release with or without octreotide long-acting release for naïve active acromegaly.

    PubMed

    Chang, Jan-Shun; Tseng, Ham-Min; Chang, Tien-Chun

    2016-06-01

    The aim of the present study was to evaluate the serial changes of GH and IGF-1 in seven patients with naïve, active acromegaly following presurgical treatment of the somatostatin analog pasireotide long-acting release (LAR) and octreotide LAR. The patients were treated with pasireotide LAR with or without octreotide LAR for two years and underwent transsphenoidal adenomectomy. After treatment with the somatostatin analogs, the surgical cure rate was similar to that in patients who underwent transsphenoidal surgery alone. Diabetes insipidus was not identified in any patients after the operation. Pasireotide LAR was effective on GH as well as IGF-1 suppression and tumor size decreasing when used as the primary therapy. Future large-population studies to investigate the surgical curative rate after presurgical treatment with somatostatin analogs in patients with acromegaly and macroadenomas close to the cavernous sinus are warranted. However, that hyperglycemia developed following pre-surgical treatment with pasireotide should take into consideration. PMID:27117887

  8. Pasireotide Therapy of Multiple Endocrine Neoplasia Type 1–Associated Neuroendocrine Tumors in Female Mice Deleted for an Men1 Allele Improves Survival and Reduces Tumor Progression

    PubMed Central

    Walls, Gerard V.; Stevenson, Mark; Soukup, Benjamin S.; Lines, Kate E.; Grossman, Ashley B.; Schmid, Herbert A.

    2016-01-01

    Pasireotide, a somatostatin analog, is reported to have anti-proliferative effects in neuroendocrine tumors (NETs). We therefore assessed the efficacy of pasireotide for treating pancreatic and pituitary NETs that develop in a mouse model of multiple endocrine neoplasia type 1 (MEN1). Men1+/− mice were treated from age 12 mo with 40 mg/kg pasireotide long-acting release formulation, or PBS, intramuscularly monthly for 9 mo. The Men1+/− mice had magnetic resonance imaging at 12 and 21 mo, and from 20 mo oral 5-bromo-2-deoxyuridine for 1 mo, to assess tumor development and proliferation, respectively. NETs were collected at age 21 mo, and proliferation and apoptosis assessed by immunohistochemistry and TUNEL assays, respectively. Pasireotide-treated Men1+/− mice had increased survival (pasireotide, 80.9% vs PBS, 65.2%; P < .05), with fewer mice developing pancreatic NETs (pasireotide, 86.9% vs PBS, 96.9%; P < .05) and smaller increases in pituitary NET volumes (pre-treated vs post-treated, 0.803 ± 0.058 mm3 vs 2.872 ± 0.728 mm3 [pasireotide] compared with 0.844 ± 0.066 mm3 vs 8.847 ±1.948 mm3 [PBS]; P < .01). In addition, pasireotide-treated mice had fewer pancreatic NETs compared with PBS-treated mice (2.36 ± 0.25 vs 3.72 ± 0.32, respectively; P < .001), with decreased proliferation in pancreatic NETs (pasireotide, 0.35 ± 0.03% vs PBS, 0.78 ± 0.08%; P < .0001) and pituitary NETs (pasireotide, 0.73 ±0.07% vs PBS, 1.81 ± 0.15%; P < .0001), but increased apoptosis in pancreatic NETs (pasireotide, 0.42 ± 0.05% vs PBS, 0.19 ± 0.03%; P < .001) and pituitary NETs (pasireotide, 14.75 ± 1.58% vs PBS, 2.35 ± 0.44%; P < .001). Thus, pasireotide increased survival and inhibited pancreatic and pituitary NET growth, thereby indicating its potential as an anti-proliferative and pro-apoptotic therapy. PMID:26990064

  9. Pasireotide and octreotide antiproliferative effects and sst2 trafficking in human pancreatic neuroendocrine tumor cultures.

    PubMed

    Mohamed, Amira; Blanchard, Marie-Pierre; Albertelli, Manuela; Barbieri, Federica; Brue, Thierry; Niccoli, Patricia; Delpero, Jean-Robert; Monges, Genevieve; Garcia, Stephane; Ferone, Diego; Florio, Tullio; Enjalbert, Alain; Moutardier, Vincent; Schonbrunn, Agnes; Gerard, Corinne; Barlier, Anne; Saveanu, Alexandru

    2014-10-01

    Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) raise difficult therapeutic problems despite the emergence of targeted therapies. Somatostatin analogs (SSA) remain pivotal therapeutic drugs. However, the tachyphylaxis and the limited antitumoral effects observed with the classical somatostatin 2 (sst2) agonists (octreotide and lanreotide) led to the development of new SSA, such as the pan sst receptor agonist pasireotide. Our aim was to compare the effects of pasireotide and octreotide on cell survival, chromogranin A (CgA) secretion, and sst2 phosphorylation/trafficking in pancreatic NET (pNET) primary cells from 15 tumors. We established and characterized the primary cultures of human pancreatic tumors (pNETs) as powerful preclinical models for understanding the biological effects of SSA. At clinically relevant concentrations (1-10 nM), pasireotide was at least as efficient as octreotide in inhibiting CgA secretion and cell viability through caspase-dependent apoptosis during short treatments, irrespective of the expression levels of the different sst receptors or the WHO grade of the parental tumor. Interestingly, unlike octreotide, which induces a rapid and persistent partial internalization of sst2 associated with its phosphorylation on Ser341/343, pasireotide did not phosphorylate sst2 and induced a rapid and transient internalization of the receptor followed by a persistent recycling at the cell surface. These results provide the first evidence, to our knowledge, of striking differences in the dynamics of sst2 trafficking in pNET cells treated with the two SSAs, but with similar efficiency in the control of CgA secretion and cell viability.

  10. Pasireotide (SIGNIFOR) in acromegaly. After treatment failure: better than pegvisomant.

    PubMed

    2016-02-01

    In a trial including 198 patients in whom several lines of treatments had failed, pasireotide normalised IGF-1 and GH levels and sometimes reduced the size of the pituitary adenoma, but often at a cost of developing diabetes. PMID:27042726

  11. Successful Medical Treatment of Adult Nesidioblastosis With Pasireotide over 3 Years

    PubMed Central

    Schwetz, Verena; Horvath, Karl; Kump, Patrizia; Lackner, Carolin; Perren, Aurel; Forrer, Flavio; Pieber, Thomas R.; Treiber, Gerlies; Sourij, Harald; Mader, Julia K.

    2016-01-01

    Abstract Nesidioblastosis is a rare cause of endogenous hyperinsulinemic hypoglycemia in adults. Diagnosis is often challenging and therapeutic options are scarce. In 2009, a 46-year-old female patient presented with recurrent severe hypoglycemia and immediate recovery after glucose ingestion. Although 72-h-fasting test was positive, various imaging technologies (sonography, computed tomography, somatostatin receptor scintigraphy, dopamine receptor positron emission tomography [DOPA-PET]) were negative. Endoscopic ultrasound revealed a lesion in the pancreatic corpus, whereas selective arterial calcium stimulation test, portal venous sampling and GLP-1-receptor scintigraphy were indicative of a lesion in the pancreatic tail, which was surgically removed. The histopathologic examination revealed beta cell hyperplasia and microadenomas expressing glucagon. After surgery, the patient was free of symptoms for 6 months, after which hypoglycemic episodes recurred. After unsuccessful treatment with corticosteroids and somatostatin analogs, treatment with pasireotide, a novel somatostatin analog with high affinity to somatostatin receptor 5 and a possible side effect of hyperglycemia, was initiated (0.6 mg BID). To date, our patient has been free of severe hypoglycemic episodes ever since. Yearly repeated imaging procedures have shown no abnormities over the last 3 years. We report for the first time that pasireotide was successfully used in the treatment of adult nesidioblastosis. PMID:27057885

  12. Pasireotide: a novel treatment for patients with acromegaly

    PubMed Central

    Cuevas-Ramos, Daniel; Fleseriu, Maria

    2016-01-01

    Morbidity and mortality rates in patients with active acromegaly are higher than the general population. Adequate biochemical control restores mortality to normal rates. Now, medical therapy has an increasingly important role in the treatment of patients with acromegaly. Somatostatin receptor ligands (SRLs) are considered the standard medical therapy, either after surgery or as a first-line therapy when surgery is deemed ineffective or is contraindicated. Overall, octreotide and lanreotide are first-generation SRLs and are effective in ~20%–70% of patients. Pegvisomant, a growth hormone receptor antagonist, controls insulin-like growth factor 1 in 65%–90% of cases. Consequently, a subset of patients (nonresponders) requires other treatment options. Drug combination therapy offers the potential for more efficacious disease control. However, the development of new medical therapies remains essential. Here, emphasis is placed on new medical therapies to control acromegaly. There is a focus on pasireotide long-acting release (LAR) (Signifor LAR®), which was approved in 2014 by the US Food and Drug Administration and the European Medicine Agency for the treatment of acromegaly. Pasireotide LAR is a long-acting somatostatin multireceptor ligand. In a Phase III clinical trial in patients with acromegaly (naïve to medical therapy or uncontrolled on a maximum dose of first-generation SRLs), 40 and 60 mg of intramuscular pasireotide LAR achieved better biochemical disease control than octreotide LAR, and tumor shrinkage was noted in both pasireotide groups. Pasireotide LAR tolerability was similar to other SRLs, except for a greater frequency and degree of hyperglycemia and diabetes mellitus. Baseline glucose may predict hyperglycemia occurrence after treatment, and careful monitoring of glycemic status and appropriate treatment is required. A precise definition of patients with acromegaly who will derive the greatest therapeutic benefit from pasireotide LAR remains to

  13. Pasireotide: a novel treatment for patients with acromegaly.

    PubMed

    Cuevas-Ramos, Daniel; Fleseriu, Maria

    2016-01-01

    Morbidity and mortality rates in patients with active acromegaly are higher than the general population. Adequate biochemical control restores mortality to normal rates. Now, medical therapy has an increasingly important role in the treatment of patients with acromegaly. Somatostatin receptor ligands (SRLs) are considered the standard medical therapy, either after surgery or as a first-line therapy when surgery is deemed ineffective or is contraindicated. Overall, octreotide and lanreotide are first-generation SRLs and are effective in ~20%-70% of patients. Pegvisomant, a growth hormone receptor antagonist, controls insulin-like growth factor 1 in 65%-90% of cases. Consequently, a subset of patients (nonresponders) requires other treatment options. Drug combination therapy offers the potential for more efficacious disease control. However, the development of new medical therapies remains essential. Here, emphasis is placed on new medical therapies to control acromegaly. There is a focus on pasireotide long-acting release (LAR) (Signifor LAR®), which was approved in 2014 by the US Food and Drug Administration and the European Medicine Agency for the treatment of acromegaly. Pasireotide LAR is a long-acting somatostatin multireceptor ligand. In a Phase III clinical trial in patients with acromegaly (naïve to medical therapy or uncontrolled on a maximum dose of first-generation SRLs), 40 and 60 mg of intramuscular pasireotide LAR achieved better biochemical disease control than octreotide LAR, and tumor shrinkage was noted in both pasireotide groups. Pasireotide LAR tolerability was similar to other SRLs, except for a greater frequency and degree of hyperglycemia and diabetes mellitus. Baseline glucose may predict hyperglycemia occurrence after treatment, and careful monitoring of glycemic status and appropriate treatment is required. A precise definition of patients with acromegaly who will derive the greatest therapeutic benefit from pasireotide LAR remains to be

  14. Pasireotide: a novel treatment for patients with acromegaly.

    PubMed

    Cuevas-Ramos, Daniel; Fleseriu, Maria

    2016-01-01

    Morbidity and mortality rates in patients with active acromegaly are higher than the general population. Adequate biochemical control restores mortality to normal rates. Now, medical therapy has an increasingly important role in the treatment of patients with acromegaly. Somatostatin receptor ligands (SRLs) are considered the standard medical therapy, either after surgery or as a first-line therapy when surgery is deemed ineffective or is contraindicated. Overall, octreotide and lanreotide are first-generation SRLs and are effective in ~20%-70% of patients. Pegvisomant, a growth hormone receptor antagonist, controls insulin-like growth factor 1 in 65%-90% of cases. Consequently, a subset of patients (nonresponders) requires other treatment options. Drug combination therapy offers the potential for more efficacious disease control. However, the development of new medical therapies remains essential. Here, emphasis is placed on new medical therapies to control acromegaly. There is a focus on pasireotide long-acting release (LAR) (Signifor LAR®), which was approved in 2014 by the US Food and Drug Administration and the European Medicine Agency for the treatment of acromegaly. Pasireotide LAR is a long-acting somatostatin multireceptor ligand. In a Phase III clinical trial in patients with acromegaly (naïve to medical therapy or uncontrolled on a maximum dose of first-generation SRLs), 40 and 60 mg of intramuscular pasireotide LAR achieved better biochemical disease control than octreotide LAR, and tumor shrinkage was noted in both pasireotide groups. Pasireotide LAR tolerability was similar to other SRLs, except for a greater frequency and degree of hyperglycemia and diabetes mellitus. Baseline glucose may predict hyperglycemia occurrence after treatment, and careful monitoring of glycemic status and appropriate treatment is required. A precise definition of patients with acromegaly who will derive the greatest therapeutic benefit from pasireotide LAR remains to be

  15. A Single-Center 10-Year Experience with Pasireotide in Cushing's Disease: Patients' Characteristics and Outcome.

    PubMed

    Trementino, L; Michetti, G; Angeletti, A; Marcelli, G; Concettoni, C; Cardinaletti, C; Polenta, B; Boscaro, M; Arnaldi, G

    2016-05-01

    Pasireotide is the first pituitary-directed drug approved for treating patients with Cushing's disease (CD). Our 10-year experience with pasireotide in CD is reported here. Twenty patients with de novo, persistent, or recurrent CD after pituitary surgery were treated with pasireotide from December 2003 to December 2014. Twelve patients were treated with pasireotide in randomized trials and 8 patients with pasireotide sc (Signifor(®); Novartis AG, Basel, Switzerland) in clinical practice. The mean treatment duration was 20.5 months (median 9 months; range, 3-72 months). Urinary free cortisol (UFC) levels mean percentage change (± SD) at last follow-up was-40.4% (± 35.1; range, 2-92%; median reduction 33.3%) with a normalization rate of 50% (10/20). Ten patients achieved sustained normalized late night salivary cortisol (LNSC) levels during treatment. LNSC normalization was associated with UFC normalization in 7/10 patients. Serum cortisol and plasma ACTH significantly decreased from baseline to last follow-up. Body weight decrease and blood pressure improvement during pasireotide treatment were independent from UFC response. Glucose profile worsening was observed in all patients except one. The frequency of diabetes mellitus increased from 40% (8/20) at baseline to 85% (17/20) at last follow-up requiring initiation of medical treatment only in 44% of patients. Pasireotide treatment was associated with sustained biochemical and clinical benefit in about 60% of CD patients. Glucose profile alteration is a frequent complication of pasireotide treatment; however, it seems to be easy to manage with diet and lifestyle intervention in almost half of the patients. PMID:27127913

  16. Management of Hyperglycemia in Patients With Acromegaly Treated With Pasireotide LAR.

    PubMed

    Samson, Susan L

    2016-09-01

    Pasireotide (Signifor(®)) long-acting release (LAR) is a next-generation somatostatin receptor ligand (SRL) approved for treatment of patients with acromegaly who have had an inadequate response to surgery or for whom surgery is not an option. Pasireotide LAR has been shown to be more effective than other SRLs in providing biochemical control in patients with acromegaly. However, hyperglycemia-related adverse events were more frequent in patients treated with pasireotide LAR than in those treated with other SRLs. Given the effectiveness of pasireotide LAR, it is important to understand whether these hyperglycemia-related events are manageable and, if so, the appropriate steps to take to manage them. In patients treated with pasireotide LAR, levels of fasting plasma glucose (FPG) and glycated hemoglobin (HbA1c) increased in the first 1-3 months and stabilized for as long as 26 months thereafter. In phase III trials of patients with acromegaly, only 3.4-3.8 % discontinued pasireotide LAR because of hyperglycemia-related adverse events. In cases in which pasireotide LAR was discontinued, FPG and HbA1c levels returned to baseline. Frequent monitoring of glucose levels is recommended, especially immediately after initiating and discontinuing pasireotide LAR. The treatment strategies suggested herein are made on the basis of available clinical data from healthy volunteers and post hoc analyses of phase III trials. Data from several clinical trials indicate a predictable and possibly reversible hyperglycemic effect that is manageable with proactive monitoring and available antidiabetic medications. PMID:27473537

  17. Effectiveness of low-dose pasireotide in a patient with Cushing's disease: antiproliferative effect and predictivity of a short pasireotide suppression test.

    PubMed

    Grossrubatscher, Erika; Zampetti, Benedetta; Dalino Ciaramella, Paolo; Doneda, Paola; Loli, Paola

    2015-08-01

    This case shows efficacy of low-dose pasireotide in biochemical and clinical control of severe hypercortisolism and in tumor volume reduction in a patient with an ACTH-secreting macroadenoma. The drug may be an option for long-term treatment in some patients where control of tumor mass is an important clinical endpoint. PMID:26331021

  18. Effectiveness of low-dose pasireotide in a patient with Cushing’s disease: antiproliferative effect and predictivity of a short pasireotide suppression test

    PubMed Central

    Grossrubatscher, Erika; Zampetti, Benedetta; Dalino Ciaramella, Paolo; Doneda, Paola; Loli, Paola

    2015-01-01

    Key Clinical Message This case shows efficacy of low-dose pasireotide in biochemical and clinical control of severe hypercortisolism and in tumor volume reduction in a patient with an ACTH-secreting macroadenoma. The drug may be an option for long-term treatment in some patients where control of tumor mass is an important clinical endpoint. PMID:26331021

  19. Effectiveness of low-dose pasireotide in a patient with Cushing's disease: antiproliferative effect and predictivity of a short pasireotide suppression test.

    PubMed

    Grossrubatscher, Erika; Zampetti, Benedetta; Dalino Ciaramella, Paolo; Doneda, Paola; Loli, Paola

    2015-08-01

    This case shows efficacy of low-dose pasireotide in biochemical and clinical control of severe hypercortisolism and in tumor volume reduction in a patient with an ACTH-secreting macroadenoma. The drug may be an option for long-term treatment in some patients where control of tumor mass is an important clinical endpoint.

  20. Evaluation of the Effects of Pasireotide LAR Administration on Lymphocele Prevention after Axillary Node Dissection for Breast Cancer: Results of a Randomized Non-Comparative Phase 2 Study

    PubMed Central

    Chéreau, Elisabeth; Uzan, Catherine; Boutmy-Deslandes, Emmanuelle; Zohar, Sarah; Bézu, Corinne; Mazouni, Chafika; Garbay, Jean-Rémi; Daraï, Emile; Rouzier, Roman

    2016-01-01

    Objective The aim of this study was to assess the efficacy (response rate centered on 80%) of a somatostatin analog with high affinity for 4 somatostatin receptors in reducing the postoperative incidence of symptomatic lymphocele formation following total mastectomy with axillary lymph node dissection. Setting This prospective, double-blind, randomised, placebo-controlled, phase 2 trial was conducted in two secondary care centres. Participants All female patients for whom mastectomy and axillary lymph node dissection were indicated were eligible for the study, including patients who had received neo-adjuvant chemotherapy. Main exclusion criteria were related to diabetes, cardiac insufficiency, disorder of cardiac conduction or hepatic failure. Interventions Patients were randomised to receive one injection of either prolonged-release pasireotide 60 mg or placebo (physiological serum), which were administered intramuscularly 7 to 10 days before the scheduled surgery. The study was conducted in a double-blind manner. Primary and Secondary Outcome Measures The primary outcome measure was the percentage of patients who did not develop post-operative axillary symptomatic lymphoceles during the 2 postoperative months. Secondary endpoints were the total quantity of lymph drained, duration and daily volume of drainage and aspirated volumes of lymph. Results Ninety-one patients were randomised. Ninety patients were evaluable: 42 patients received pasireotide, and 48 patients received placebo. The mean estimated response rate were 62.4% (95% Credibility Interval [CrI]: 48.6%-75.3%) in the treatment group and 50.2% (95% CrI: 37.6%-62.8%) in the placebo group. Overall safety was comparable across groups, and one serious adverse event occurred. In the treatment group, one patient with known insulin-depe*ndent diabetes required hospitalization for hyperglycaemia. Conclusions With this phase 2 preliminary study, even if our results indicate a trend towards a reduction in

  1. From bulk to plasmonic nanoparticle surfaces: the behavior of two potent therapeutic peptides, octreotide and pasireotide.

    PubMed

    Hernández, Belén; López-Tobar, Eduardo; Sanchez-Cortes, Santiago; Coïc, Yves-Marie; Baron, Bruno; Chenal, Alexandre; Kruglik, Sergei G; Pflüger, Fernando; Cohen, Régis; Ghomi, Mahmoud

    2016-09-21

    Octreotide and pasireotide are two cyclic somatostatin analogues with an important clinical use in the treatment and diagnosis of neuroendocrine tumors. Herein, by the combined use of several techniques (UV-visible absorption, fluorescence, circular dichroism, ζ-potential, transmission electron microscopy, Raman scattering, surface-enhanced Raman scattering, and quantum mechanical calculations) we have followed the structural dynamics of these analogues in the bulk, as well as their binding sites on plasmonic (gold and silver) colloids. In contrast to the previously derived conclusions, the two peptides seem to possess completely different conformational features. Octreotide, a cyclic octapeptide, is formed by a moderately flexible type-II'β-turn maintained by a deformable disulfide linkage. Pasireotide, in which the cyclic character is made possible by peptide bonds, manifests a rigid backbone formed by two oppositely placed tight turns of different types, i.e.γ-turn and type-I β-turn. Owing to their cationic character, both analogues induce aggregation of negatively charged gold and silver colloids. Nevertheless, despite their notable structural differences, both peptides bind onto gold nanoparticles through their unique d-Trp residue. In contrast, their binding to silver colloids seems to be of electrostatic nature, as formed through monodentate or bidentate ionic pairs. PMID:27537101

  2. Clinical management of critically ill patients with Cushing's disease due to ACTH-secreting pituitary macroadenomas: effectiveness of presurgical treatment with pasireotide.

    PubMed

    Cannavo, S; Messina, E; Albani, A; Ferrau, F; Barresi, V; Priola, S; Esposito, F; Angileri, F

    2016-06-01

    The management of critically ill Cushing's disease (CD) patients is extremely challenging. Pasireotide is indicated for the treatment of CD patients when pituitary surgery is unfeasible or has not been curative, but no data are available about the use of this drug as pre-operative treatment in critically ill patients. We report the effects of presurgical pasireotide therapy in CD patients in whom hypercortisolism caused life-threatening hypokalemia, alkalosis, and cardio-respiratory complications precluding surgical approach. Clinical, biochemical, and radiological data of two critically ill patients with ACTH-secreting pituitary macroadenoma, before and during first-line presurgical pasireotide treatment (600 μg s.c. bid). During the first 21 days of treatment, pasireotide therapy induced a rapid, partial decrease of plasma ACTH, serum cortisol, and urinary free cortisol levels, with the consequent normalization of serum potassium concentration and arterial blood gases parameters, in both the patients. They did not experience unmanageable side effects and underwent endoscopic transsphenoidal surgery after 4 weeks of effective treatment. Pre-operative MRI evaluation did not show pituitary tumor shrinkage. Surgical cure of CD was obtained in the first patient, while debulking allowed the pharmacological control of hypercortisolism in the second case. We suggest that pasireotide can induce a rapid improvement of clinical and metabolic conditions in critically ill CD patients in whom surgical approach is considered hazardous and need to be delayed.

  3. The treatment with pasireotide in Cushing's disease: effects of long-term treatment on tumor mass in the experience of a single center.

    PubMed

    Simeoli, Chiara; Auriemma, Renata Simona; Tortora, Fabio; De Leo, Monica; Iacuaniello, Davide; Cozzolino, Alessia; De Martino, Maria Cristina; Pivonello, Claudia; Mainolfi, Ciro Gabriele; Rossi, Riccardo; Cirillo, Sossio; Colao, Annamaria; Pivonello, Rosario

    2015-12-01

    Pasireotide is the first medical therapy officially approved for the treatment of adult patients with Cushing's disease (CD) who experienced a failure of pituitary surgery or are not candidates for surgery and require medical therapeutic intervention. The current study aimed at investigating the effects of long-term treatment with pasireotide (up to 24 months) on tumor mass in a group of patients with CD, participating to a phase III study. Fourteen CD patients entered the phase III clinical trial CSOM230B2305 at Naples Center, and eight (seven women, one man, aged 38.9 ± 17.6 years), including seven with a microadenoma and one with a macroadenoma, received treatment with pasireotide at the dose of 600-1200 µg bid for at least 6 months, and were considered for the analysis of the study. These eight patients were subjected to the evaluation of pituitary tumor volume by pituitary MRI, together with the evaluation of urinary cortisol levels, at baseline and every 6 months for the entire period of treatment. Pasireotide treatment induced full disease control in 37.5 % and partial disease control in 37.5 % after 6 months, whereas full and partial disease control after 12 months was obtained in 28.6 % and in 57.1 % of patients, respectively. A significant (>25 %) reduction in tumor volume was found in 62.5 % and in 100 % of patients, after 6 and 12 months, respectively. In particular, after 6 months, a slight tumor shrinkage (between 25.1 and 50 %) was observed in 25 %, moderate (50.1-75 %) in 25 %, and marked (>75 %) in 12.5 % of patients, whereas after 12 months, a slight tumor shrinkage was observed in 43 %, moderate in 14 %, and marked in 43 % of patients. In 25 % of patients (two patients), a marked tumor shrinkage was recorded, with tumor mass disappearance in one case; this tumor shrinkage was associated to rapid and sustained biochemical remission up to 24 months of continuous pasireotide treatment. These two cases represent the first cases with a documentation

  4. Somatostatin Agonist Pasireotide Promotes a Physiological State Resembling Short-Day Acclimation in the Photoperiodic Male Siberian Hamster (Phodopus sungorus).

    PubMed

    Dumbell, R A; Scherbarth, F; Diedrich, V; Schmid, H A; Steinlechner, S; Barrett, P

    2015-07-01

    The timing of growth in seasonal mammals is inextricably linked to food availability. This is exemplified in the Siberian hamster (Phodopus sungorus), which uses the annual cycle of photoperiod to optimally programme energy expenditure in anticipation of seasonal fluctuations in food resources. During the autumn, energy expenditure is progressively minimised by physiological adaptations, including a 30% reduction in body mass, comprising a reduction in both fat and lean tissues. However, the mechanistic basis of this adaptation is still unexplained. We hypothesised that growth hormone (GH) was a likely candidate to underpin these reversible changes in body mass. Administration of pasireotide, a long-acting somatostatin receptor agonist developed for the treatment of acromegaly, to male hamsters under a long-day (LD) photoperiod produced a body weight loss. This comprised a reduction in lean and fat mass, including kidneys, testes and brown adipose tissue, typically found in short-day (SD) housed hamsters. Furthermore, when administered to hamsters switched from SD to LD, pasireotide retarded the body weight increase compared to vehicle-treated hamsters. Pasireotide did not alter photoperiod-mediated changes in hypothalamic energy balance gene expression but altered the expression of Srif mRNA expression in the periventricular nucleus and Ghrh mRNA expression in the arcuate nucleus consistent with a reduction in GH feedback and concurrent with reduced serum insulin-like growth factor-1. Conversely, GH treatment of SD hamsters increased body mass, which included increased mass of liver and kidneys. Together, these data indicate a role for the GH axis in the determination of seasonal body mass of the Siberian hamster.

  5. Lunar Analog

    NASA Technical Reports Server (NTRS)

    Cromwell, Ronita L.

    2009-01-01

    In this viewgraph presentation, a ground-based lunar analog is developed for the return of manned space flight to the Moon. The contents include: 1) Digital Astronaut; 2) Bed Design; 3) Lunar Analog Feasibility Study; 4) Preliminary Data; 5) Pre-pilot Study; 6) Selection of Stockings; 7) Lunar Analog Pilot Study; 8) Bed Design for Lunar Analog Pilot.

  6. Analog earthquakes

    SciTech Connect

    Hofmann, R.B.

    1995-09-01

    Analogs are used to understand complex or poorly understood phenomena for which little data may be available at the actual repository site. Earthquakes are complex phenomena, and they can have a large number of effects on the natural system, as well as on engineered structures. Instrumental data close to the source of large earthquakes are rarely obtained. The rare events for which measurements are available may be used, with modfications, as analogs for potential large earthquakes at sites where no earthquake data are available. In the following, several examples of nuclear reactor and liquified natural gas facility siting are discussed. A potential use of analog earthquakes is proposed for a high-level nuclear waste (HLW) repository.

  7. Triptycene analogs

    NASA Technical Reports Server (NTRS)

    Hua, Duy (Inventor); Perchellet, Jean-Pierre (Inventor)

    2004-01-01

    This invention provides analogs of triptycene which are useful as anticancer drugs, as well as for other uses. The potency of these compounds is in a similar magnitude as daunomycin, a currently used anticancer drug. Each compound of the invention produces one or more desired effects (blocking nucleoside transport, inhibiting nucleic acid or protein syntheses, decreasing the proliferation and viability of cancer cells, inducing DNA fragmentation or retaining their effectiveness against multidrug-resistant tumor cells).

  8. Analog current mode analog/digital converter

    NASA Technical Reports Server (NTRS)

    Hadidi, Khayrollah (Inventor)

    1996-01-01

    An improved subranging or comparator circuit is provided for an analog-to-digital converter. As a subranging circuit, the circuit produces a residual signal representing the difference between an analog input signal and an analog of a digital representation. This is achieved by subdividing the digital representation into two or more parts and subtracting from the analog input signal analogs of each of the individual digital portions. In another aspect of the present invention, the subranging circuit comprises two sets of differential input pairs in which the transconductance of one differential input pair is scaled relative to the transconductance of the other differential input pair. As a consequence, the same resistor string may be used for two different digital-to-analog converters of the subranging circuit.

  9. Radioactive Decay - An Analog.

    ERIC Educational Resources Information Center

    McGeachy, Frank

    1988-01-01

    Presents an analog of radioactive decay that allows the student to grasp the concept of half life and the exponential nature of the decay process. The analog is devised to use small, colored, plastic poker chips or counters. Provides the typical data and a graph which supports the analog. (YP)

  10. Analog, still without fear

    NASA Astrophysics Data System (ADS)

    Delagrange, A. D.

    1984-09-01

    This report is an update of one issued in 1977 which predicted that the predicted death of analog circuitry (also called linear) would not occur; in fact, the patient appeared remarkably healthy. The report proved correct. We have the same situation again today: the same predictions and counter-prediction. Each year brings significant advances in the field of analog integrated circuitry. Many of the traditional arguments against analog circuitry are no longer valid. This report attempts to summarize what is available now, and what can (and cannot) be done with analog integrated circuits. It defines analog and makes some comparisons with digital. The most common types of analog integrated circuits are then listed and discussed. Lastly, some design and trouble-shooting hints are given, and the state-of-the-art is discussed.

  11. Nonvolatile Analog Memory

    NASA Technical Reports Server (NTRS)

    MacLeod, Todd C. (Inventor)

    2007-01-01

    A nonvolatile analog memory uses pairs of ferroelectric field effect transistors (FFETs). Each pair is defined by a first FFET and a second FFET. When an analog value is to be stored in one of the pairs, the first FFET has a saturation voltage applied thereto, and the second FFET has a storage voltage applied thereto that is indicative of the analog value. The saturation and storage voltages decay over time in accordance with a known decay function that is used to recover the original analog value when the pair of FFETs is read.

  12. Analog synthetic biology.

    PubMed

    Sarpeshkar, R

    2014-03-28

    We analyse the pros and cons of analog versus digital computation in living cells. Our analysis is based on fundamental laws of noise in gene and protein expression, which set limits on the energy, time, space, molecular count and part-count resources needed to compute at a given level of precision. We conclude that analog computation is significantly more efficient in its use of resources than deterministic digital computation even at relatively high levels of precision in the cell. Based on this analysis, we conclude that synthetic biology must use analog, collective analog, probabilistic and hybrid analog-digital computational approaches; otherwise, even relatively simple synthetic computations in cells such as addition will exceed energy and molecular-count budgets. We present schematics for efficiently representing analog DNA-protein computation in cells. Analog electronic flow in subthreshold transistors and analog molecular flux in chemical reactions obey Boltzmann exponential laws of thermodynamics and are described by astoundingly similar logarithmic electrochemical potentials. Therefore, cytomorphic circuits can help to map circuit designs between electronic and biochemical domains. We review recent work that uses positive-feedback linearization circuits to architect wide-dynamic-range logarithmic analog computation in Escherichia coli using three transcription factors, nearly two orders of magnitude more efficient in parts than prior digital implementations. PMID:24567476

  13. Hydraulic Capacitor Analogy

    ERIC Educational Resources Information Center

    Baser, Mustafa

    2007-01-01

    Students have difficulties in physics because of the abstract nature of concepts and principles. One of the effective methods for overcoming students' difficulties is the use of analogies to visualize abstract concepts to promote conceptual understanding. According to Iding, analogies are consistent with the tenets of constructivist learning…

  14. Analog synthetic biology

    PubMed Central

    Sarpeshkar, R.

    2014-01-01

    We analyse the pros and cons of analog versus digital computation in living cells. Our analysis is based on fundamental laws of noise in gene and protein expression, which set limits on the energy, time, space, molecular count and part-count resources needed to compute at a given level of precision. We conclude that analog computation is significantly more efficient in its use of resources than deterministic digital computation even at relatively high levels of precision in the cell. Based on this analysis, we conclude that synthetic biology must use analog, collective analog, probabilistic and hybrid analog–digital computational approaches; otherwise, even relatively simple synthetic computations in cells such as addition will exceed energy and molecular-count budgets. We present schematics for efficiently representing analog DNA–protein computation in cells. Analog electronic flow in subthreshold transistors and analog molecular flux in chemical reactions obey Boltzmann exponential laws of thermodynamics and are described by astoundingly similar logarithmic electrochemical potentials. Therefore, cytomorphic circuits can help to map circuit designs between electronic and biochemical domains. We review recent work that uses positive-feedback linearization circuits to architect wide-dynamic-range logarithmic analog computation in Escherichia coli using three transcription factors, nearly two orders of magnitude more efficient in parts than prior digital implementations. PMID:24567476

  15. Challenges in Using Analogies

    ERIC Educational Resources Information Center

    Lin, Shih-Yin; Singh, Chandralekha

    2011-01-01

    Learning physics requires understanding the applicability of fundamental principles in a variety of contexts that share deep features. One way to help students learn physics is via analogical reasoning. Students can be taught to make an analogy between situations that are more familiar or easier to understand and another situation where the same…

  16. Meat analog: a review.

    PubMed

    Malav, O P; Talukder, S; Gokulakrishnan, P; Chand, S

    2015-01-01

    The health-conscious consumers are in search of nutritious and convenient food item which can be best suited in their busy life. The vegetarianism is the key for the search of such food which resembles the meat in respect of nutrition and sensory characters, but not of animal origin and contains vegetable or its modified form, this is the point when meat analog evolved out and gets shape. The consumers gets full satisfaction by consumption of meat analog due to its typical meaty texture, appearance and the flavor which are being imparted during the skilled production of meat analog. The supplement of protein in vegetarian diet through meat alike food can be fulfilled by incorporating protein-rich vegetative food grade materials in meat analog and by adopting proper technological process which can promote the proper fabrication of meat analog with acceptable meat like texture, appearance, flavor, etc. The easily available vegetables, cereals, and pulses in India have great advantages and prospects to be used in food products and it can improve the nutritional and functional characters of the food items. The various form and functional characters of food items are available world over and attracts the meat technologists and the food processors to bring some innovativeness in meat analog and its presentation and marketability so that the acceptability of meat analog can be overgrown by the consumers.

  17. Challenges in Using Analogies

    NASA Astrophysics Data System (ADS)

    Lin, Shih-Yin; Singh, Chandralekha

    2011-11-01

    Learning physics requires understanding the applicability of fundamental principles in a variety of contexts that share deep features.1-7 One way to help students learn physics is via analogical reasoning. Students can be taught to make an analogy between situations that are more familiar or easier to understand and another situation where the same physics principle is involved but that is more difficult to handle. Here, we examine introductory physics students' ability to use analogies in solving problems involving Newton's second law. Students enrolled in an algebra-based introductory physics course were given a solved problem involving tension in a rope and were then asked to solve another problem for which the physics is very similar but involved a frictional force. They were asked to point out the similarities between the two problems and then use the analogy to solve the friction problem.

  18. Fatty acid analogs

    DOEpatents

    Elmaleh, David R.; Livni, Eli

    1985-01-01

    In one aspect, a radioactively labeled analog of a fatty acid which is capable of being taken up by mammalian tissue and which exhibits an in vivo beta-oxidation rate below that with a corresponding radioactively labeled fatty acid.

  19. FGF growth factor analogs

    DOEpatents

    Zamora, Paul O.; Pena, Louis A.; Lin, Xinhua; Takahashi, Kazuyuki

    2012-07-24

    The present invention provides a fibroblast growth factor heparin-binding analog of the formula: ##STR00001## where R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, X, Y and Z are as defined, pharmaceutical compositions, coating compositions and medical devices including the fibroblast growth factor heparin-binding analog of the foregoing formula, and methods and uses thereof.

  20. Gravito-electromagnetic analogies

    NASA Astrophysics Data System (ADS)

    Costa, L. Filipe O.; Natário, José

    2014-10-01

    We reexamine and further develop different gravito-electromagnetic (GEM) analogies found in the literature, and clarify the connection between them. Special emphasis is placed in two exact physical analogies: the analogy based on inertial fields from the so-called "1+3 formalism", and the analogy based on tidal tensors. Both are reformulated, extended and generalized. We write in both formalisms the Maxwell and the full exact Einstein field equations with sources, plus the algebraic Bianchi identities, which are cast as the source-free equations for the gravitational field. New results within each approach are unveiled. The well known analogy between linearized gravity and electromagnetism in Lorentz frames is obtained as a limiting case of the exact ones. The formal analogies between the Maxwell and Weyl tensors are also discussed, and, together with insight from the other approaches, used to physically interpret gravitational radiation. The precise conditions under which a similarity between gravity and electromagnetism occurs are discussed, and we conclude by summarizing the main outcome of each approach.

  1. Electrical Circuits and Water Analogies

    ERIC Educational Resources Information Center

    Smith, Frederick A.; Wilson, Jerry D.

    1974-01-01

    Briefly describes water analogies for electrical circuits and presents plans for the construction of apparatus to demonstrate these analogies. Demonstrations include series circuits, parallel circuits, and capacitors. (GS)

  2. Electrical analogous in viscoelasticity

    NASA Astrophysics Data System (ADS)

    Ala, Guido; Di Paola, Mario; Francomano, Elisa; Li, Yan; Pinnola, Francesco P.

    2014-07-01

    In this paper, electrical analogous models of fractional hereditary materials are introduced. Based on recent works by the authors, mechanical models of materials viscoelasticity behavior are firstly approached by using fractional mathematical operators. Viscoelastic models have elastic and viscous components which are obtained by combining springs and dashpots. Various arrangements of these elements can be used, and all of these viscoelastic models can be equivalently modeled as electrical circuits, where the spring and dashpot are analogous to the capacitance and resistance, respectively. The proposed models are validated by using modal analysis. Moreover, a comparison with numerical experiments based on finite difference time domain method shows that, for long time simulations, the correct time behavior can be obtained only with modal analysis. The use of electrical analogous in viscoelasticity can better reveal the real behavior of fractional hereditary materials.

  3. Analogical Reasoning in Geometry Education

    ERIC Educational Resources Information Center

    Magdas, Ioana

    2015-01-01

    The analogical reasoning isn't used only in mathematics but also in everyday life. In this article we approach the analogical reasoning in Geometry Education. The novelty of this article is a classification of geometrical analogies by reasoning type and their exemplification. Our classification includes: analogies for understanding and setting a…

  4. Digital and analog communication systems

    NASA Technical Reports Server (NTRS)

    Shanmugam, K. S.

    1979-01-01

    The book presents an introductory treatment of digital and analog communication systems with emphasis on digital systems. Attention is given to the following topics: systems and signal analysis, random signal theory, information and channel capacity, baseband data transmission, analog signal transmission, noise in analog communication systems, digital carrier modulation schemes, error control coding, and the digital transmission of analog signals.

  5. Analogy, explanation, and proof

    PubMed Central

    Hummel, John E.; Licato, John; Bringsjord, Selmer

    2014-01-01

    People are habitual explanation generators. At its most mundane, our propensity to explain allows us to infer that we should not drink milk that smells sour; at the other extreme, it allows us to establish facts (e.g., theorems in mathematical logic) whose truth was not even known prior to the existence of the explanation (proof). What do the cognitive operations underlying the inference that the milk is sour have in common with the proof that, say, the square root of two is irrational? Our ability to generate explanations bears striking similarities to our ability to make analogies. Both reflect a capacity to generate inferences and generalizations that go beyond the featural similarities between a novel problem and familiar problems in terms of which the novel problem may be understood. However, a notable difference between analogy-making and explanation-generation is that the former is a process in which a single source situation is used to reason about a single target, whereas the latter often requires the reasoner to integrate multiple sources of knowledge. This seemingly small difference poses a challenge to the task of marshaling our understanding of analogical reasoning to understanding explanation. We describe a model of explanation, derived from a model of analogy, adapted to permit systematic violations of this one-to-one mapping constraint. Simulation results demonstrate that the resulting model can generate explanations for novel explananda and that, like the explanations generated by human reasoners, these explanations vary in their coherence. PMID:25414655

  6. Arterial Pressure Analog.

    ERIC Educational Resources Information Center

    Heusner, A. A.; Tracy, M. L.

    1980-01-01

    Describes a simple hydraulic analog which allows students to explore some physical aspects of the cardiovascular system and provides them with a means to visualize and conceptualize these basic principles. Simulates the behavior of arterial pressure in response to changes in heart rate, stroke volume, arterial compliance, and peripheral…

  7. Quantum Analog Computing

    NASA Technical Reports Server (NTRS)

    Zak, M.

    1998-01-01

    Quantum analog computing is based upon similarity between mathematical formalism of quantum mechanics and phenomena to be computed. It exploits a dynamical convergence of several competing phenomena to an attractor which can represent an externum of a function, an image, a solution to a system of ODE, or a stochastic process.

  8. Reasoning through Instructional Analogies

    ERIC Educational Resources Information Center

    Kapon, Shulamit; diSessa, Andrea A.

    2012-01-01

    This article aims to account for students' assessments of the plausibility and applicability of analogical explanations, and individual differences in these assessments, by analyzing properties of students' underlying knowledge systems. We developed a model of explanation and change in explanation focusing on knowledge elements that provide a…

  9. How Analogy Drives Physics

    SciTech Connect

    Hofstadter, Doug

    2004-05-05

    Many new ideas in theoretical physics come from analogies to older ideas in physics. For instance, the abstract notion of 'isospin' (or isotopic spin) originated in the prior concept of 'spin' (quantized angular momentum); likewise, the concept of 'phonon' (quantum of sound, or quantized collective excitation of a crystal) was based on the prior concept of 'photon' (quantum of light, or quantized element of the electromagnetic field). But these two examples, far from being exceptions, in fact represent the bread and butter of inventive thinking in physics. In a nutshell, intraphysics analogy-making -- borrowing by analogy with something already known in another area of physics -- is central to the progress of physics. The aim of this talk is to reveal the pervasiveness -- indeed, the indispensability -- of this kind of semi-irrational, wholly intuitive type of thinking (as opposed to more deductive mathematical inference) in the mental activity known as 'doing physics'. Speculations as to why wild analogical leaps are so crucial to the act of discovery in physics (as opposed to other disciplines) will be offered.

  10. Analog signal isolation techniques

    SciTech Connect

    Beadle, E.R.

    1992-12-31

    This paper discusses several techniques for isolating analog signals in an accelerator environment. The techniques presented here encompass isolation amplifiers, voltage-to-frequency converters (VIFCs), transformers, optocouplers, discrete fiber optics, and commercial fiber optic links. Included within the presentation of each method are the design issues that must be considered when selecting the isolation method for a specific application.

  11. Analog signal isolation techniques

    SciTech Connect

    Beadle, E.R.

    1992-01-01

    This paper discusses several techniques for isolating analog signals in an accelerator environment. The techniques presented here encompass isolation amplifiers, voltage-to-frequency converters (VIFCs), transformers, optocouplers, discrete fiber optics, and commercial fiber optic links. Included within the presentation of each method are the design issues that must be considered when selecting the isolation method for a specific application.

  12. Terrestrial Spaceflight Analogs: Antarctica

    NASA Technical Reports Server (NTRS)

    Crucian, Brian

    2013-01-01

    Alterations in immune cell distribution and function, circadian misalignment, stress and latent viral reactivation appear to persist during Antarctic winterover at Concordia Station. Some of these changes are similar to those observed in Astronauts, either during or immediately following spaceflight. Others are unique to the Concordia analog. Based on some initial immune data and environmental conditions, Concordia winterover may be an appropriate analog for some flight-associated immune system changes and mission stress effects. An ongoing smaller control study at Neumayer III will address the influence of the hypoxic variable. Changes were observed in the peripheral blood leukocyte distribution consistent with immune mobilization, and similar to those observed during spaceflight. Alterations in cytokine production profiles were observed during winterover that are distinct from those observed during spaceflight, but potentially consistent with those observed during persistent hypobaric hypoxia. The reactivation of latent herpesviruses was observed during overwinter/isolation, that is consistently associated with dysregulation in immune function.

  13. Analog storage integrated circuit

    DOEpatents

    Walker, J. T.; Larsen, R. S.; Shapiro, S. L.

    1989-01-01

    A high speed data storage array is defined utilizing a unique cell design for high speed sampling of a rapidly changing signal. Each cell of the array includes two input gates between the signal input and a storage capacitor. The gates are controlled by a high speed row clock and low speed column clock so that the instantaneous analog value of the signal is only sampled and stored by each cell on coincidence of the two clocks.

  14. Antarctic analogs for Enceladus

    NASA Astrophysics Data System (ADS)

    Murray, A. E.; Andersen, D. T.; McKay, C. P.

    2014-12-01

    Enceladus is a new world for Astrobiology. The Cassini discovery of the icy plume emanating from the South Polar region indicates an active world, where detection of water, organics, sodium, and nano-particle silica in the plume strongly suggests that the source is a subsurface salty ocean reservoir. Recent gravity data from Cassini confirms the presence of a regional sea extending north to 50°S. An ocean habitat under a thick ice cover is perhaps a recurring theme in the Outer Solar System, but what makes Enceladus unique is that the plume jetting out into space is carrying samples of this ocean. Therefore, through the study of Enceladus' plumes we can gain new insights not only of a possible habitable world in the Solar Systems, but also about the formation and evolution of other icy-satellites. Cassini has been able to fly through this plume - effectively sampling the ocean. It is time to plan for future missions that do more detailed analyses, possibly return samples back to Earth and search for evidence of life. To help prepare for such missions, the need for earth-based analog environments is essential for logistical, methodological (life detection) and theoretical development. We have undertaken studies of two terrestrial environments that are close analogs to Enceladus' ocean: Lake Vida and Lake Untersee - two ice-sealed Antarctic lakes that represent physical, chemical and possibly biological analogs for Enceladus. By studying the diverse biology and physical and chemical constraints to life in these two unique lakes we will begin to understand the potential habitability of Enceladus and other icy moons, including possible sources of nutrients and energy, which together with liquid water are the key ingredients for life. Analog research such as this will also enable us to develop and test new strategies to search for evidence of life on Enceladus.

  15. Analog storage integrated circuit

    DOEpatents

    Walker, J.T.; Larsen, R.S.; Shapiro, S.L.

    1989-03-07

    A high speed data storage array is defined utilizing a unique cell design for high speed sampling of a rapidly changing signal. Each cell of the array includes two input gates between the signal input and a storage capacitor. The gates are controlled by a high speed row clock and low speed column clock so that the instantaneous analog value of the signal is only sampled and stored by each cell on coincidence of the two clocks. 6 figs.

  16. The promise of analog computation

    NASA Astrophysics Data System (ADS)

    MacLennan, B. J.

    2014-10-01

    Future computing paradigms and technologies will have to be more like the physical processes by which they are realized, and because these processes are primarily continuous, post-Moore's law computing will involve an increased use of analog computation. Traditionally analog computers have computed ordinary differential equations of time, but analog field computation permits massively parallel temporal integration of partial differential equations. In principle many different physical media - not just electronics - can be exploited to implement the basic operations of analog computing, a small number of which are sufficient to approximate a wide variety of analog computations, thus providing a basis for universal analog computation and general-purpose analog computers. The contentious issue of the computational power of analog computers is addressed best on its own terms, rather by asking it within the context of Church-Turing computation, which distorts the relevant questions and their answers.

  17. Neural Analog Information Processing

    NASA Astrophysics Data System (ADS)

    Hecht-Nielsen, Robert

    1982-07-01

    Neural Analog Information Processing (NAIP) is an effort to develop general purpose pattern classification architectures based upon biological information processing principles. This paper gives an overview of NAIP and its relationship to the previous work in neural modeling from which its fundamental principles are derived. It also presents a theorem concerning the stability of response of a slab (a two dimensional array of identical simple processing units) to time-invariant (spatial) patterns. An experiment (via computer emulation) demonstrating classification of a spatial pattern by a simple, but complete NAIP architecture is described. A concept for hardware implementation of NAIP architectures is briefly discussed.

  18. Antarctic Space Analog Program

    NASA Technical Reports Server (NTRS)

    Palinkas, Lawrence A; Gunderson, E. K. Eric; Johnson, Jeffrey C.; Holland, Albert W.

    1998-01-01

    The primary aim of this project was to examine group dynamics and individual performance in extreme, isolated environments and identify human factors requirements for long-duration space missions using data collected in an analog environment. Specifically, we wished to determine: 1) the characteristics of social relations in small groups of individuals living and working together in extreme, isolated environments, and 2) the environmental, social and psychological determinants of performance effectiveness in such groups. These two issues were examined in six interrelated studies using data collected in small, isolated research stations in Antarctica from 1963 to the present. Results from these six studies indicated that behavior and performance on long-duration space flights is likely to be seasonal or cyclical, situational, social, and salutogenic in nature. The project responded to two NASA program emphases for FY 1997 as described in the NRA: 1) the primary emphasis of the Behavior and Performance Program on determining long-term individual and group performance responses to space, identifying critical factors affecting those responses and understanding underlying mechanisms involved in behavior and performance, and developing and using ground-based models and analogs for studying space-related behavior and performance; and 2) the emphasis of the Data Analysis Program on extended data analysis. Results from the study were used to develop recommendations for the design and development of pre-flight crew training and in-flight psychological countermeasures for long-duration manned space missions.

  19. Vorticity in analog gravity

    NASA Astrophysics Data System (ADS)

    Cropp, Bethan; Liberati, Stefano; Turcati, Rodrigo

    2016-06-01

    In the analog gravity framework, the acoustic disturbances in a moving fluid can be described by an equation of motion identical to a relativistic scalar massless field propagating in curved space-time. This description is possible only when the fluid under consideration is barotropic, inviscid, and irrotational. In this case, the propagation of the perturbations is governed by an acoustic metric that depends algebrically on the local speed of sound, density, and the background flow velocity, the latter assumed to be vorticity-free. In this work we provide a straightforward extension in order to go beyond the irrotational constraint. Using a charged—relativistic and nonrelativistic—Bose-Einstein condensate as a physical system, we show that in the low-momentum limit and performing the eikonal approximation we can derive a d’Alembertian equation of motion for the charged phonons where the emergent acoustic metric depends on flow velocity in the presence of vorticity.

  20. Mars inflatable greenhouse analog.

    PubMed

    Sadler, Philip D; Giacomelli, Gene A

    2002-01-01

    Light intensities on the Martian surface can possibly support a bioregenerative life support system (BLSS) utilizing natural sunlight for hydroponic crop production, if a suitable controlled environment can be provided. Inflatable clear membrane structures offer low mass, are more easily transported than a rigid structure, and are good candidates for providing a suitable controlled environment for crop production. Cable culture is one hydroponic growing system that can take advantage of the beneficial attributes of the inflatable structure. An analog of a Mars inflatable greenhouse can provide researchers data on issues such as crew time requirements for operation, productivity for BLSS, human factors, and much more at a reasonable cost. This is a description of one such design.

  1. Mars inflatable greenhouse analog.

    PubMed

    Sadler, Philip D; Giacomelli, Gene A

    2002-01-01

    Light intensities on the Martian surface can possibly support a bioregenerative life support system (BLSS) utilizing natural sunlight for hydroponic crop production, if a suitable controlled environment can be provided. Inflatable clear membrane structures offer low mass, are more easily transported than a rigid structure, and are good candidates for providing a suitable controlled environment for crop production. Cable culture is one hydroponic growing system that can take advantage of the beneficial attributes of the inflatable structure. An analog of a Mars inflatable greenhouse can provide researchers data on issues such as crew time requirements for operation, productivity for BLSS, human factors, and much more at a reasonable cost. This is a description of one such design. PMID:11987303

  2. Analog and digital signal processing

    NASA Astrophysics Data System (ADS)

    Baher, H.

    The techniques of signal processing in both the analog and digital domains are addressed in a fashion suitable for undergraduate courses in modern electrical engineering. The topics considered include: spectral analysis of continuous and discrete signals, analysis of continuous and discrete systems and networks using transform methods, design of analog and digital filters, digitization of analog signals, power spectrum estimation of stochastic signals, FFT algorithms, finite word-length effects in digital signal processes, linear estimation, and adaptive filtering.

  3. [Analogies and analogy research in technical biology and bionics].

    PubMed

    Nachtigall, Werner

    2010-01-01

    The procedural approaches of Technical Biology and Bionics are characterized, and analogy research is identified as their common basis. The actual creative aspect in bionical research lies in recognizing and exploiting technically oriented analogies underlying a specific biological prototype to indicate a specific technical application.

  4. FET comparator detects analog signal levels without loading analog device

    NASA Technical Reports Server (NTRS)

    Wallace, H. L.

    1966-01-01

    FET comparator circuit detects discrete analog computer output levels without excessively loading the output amplifier of the computer. An FET common source amplifier is coupled by a differential amplifier to a bistable transistor flip-flop. This circuit provides a digital output for analog voltages above or below a predetermined level.

  5. Producing and Recognizing Analogical Relations

    ERIC Educational Resources Information Center

    Lipkens, Regina; Hayes, Steven C.

    2009-01-01

    Analogical reasoning is an important component of intelligent behavior, and a key test of any approach to human language and cognition. Only a limited amount of empirical work has been conducted from a behavior analytic point of view, most of that within Relational Frame Theory (RFT), which views analogy as a matter of deriving relations among…

  6. Drawing Analogies in Environmental Education

    ERIC Educational Resources Information Center

    Affifi, Ramsey

    2014-01-01

    Reconsidering the origin, process, and outcomes of analogy-making suggests practices for environmental educators who strive to disengage humans from the isolating illusions of dichotomizing frameworks. We can view analogies as outcomes of developmental processes within which human subjectivity is but an element, threading our sense of self back…

  7. Natural analog studies: Licensing perspective

    SciTech Connect

    Bradbury, J.W.

    1995-09-01

    This report describes the licensing perspective of the term {open_quotes}natural analog studies{close_quotes} as used in CFR Part 60. It describes the misunderstandings related to its definition which has become evident during discussions at the U.S Nuclear Regulatory Commission meetings and tries to clarify the appropriate applications of natural analog studies to aspects of repository site characterization.

  8. Pharmacological targeting of the protein synthesis mTOR/4E-BP1 pathway in cancer-associated fibroblasts abrogates pancreatic tumour chemoresistance

    PubMed Central

    Duluc, Camille; Moatassim-Billah, Siham; Chalabi-Dchar, Mounira; Perraud, Aurélie; Samain, Rémi; Breibach, Florence; Gayral, Marion; Cordelier, Pierre; Delisle, Marie-Bernadette; Bousquet-Dubouch, Marie-Pierre; Tomasini, Richard; Schmid, Herbert; Mathonnet, Muriel; Pyronnet, Stéphane; Martineau, Yvan; Bousquet, Corinne

    2015-01-01

    Pancreatic ductal adenocarcinoma (PDAC) is extremely stroma-rich. Cancer-associated fibroblasts (CAFs) secrete proteins that activate survival and promote chemoresistance of cancer cells. Our results demonstrate that CAF secretome-triggered chemoresistance is abolished upon inhibition of the protein synthesis mTOR/4E-BP1 regulatory pathway which we found highly activated in primary cultures of α-SMA-positive CAFs, isolated from human PDAC resections. CAFs selectively express the sst1 somatostatin receptor. The SOM230 analogue (Pasireotide) activates the sst1 receptor and inhibits the mTOR/4E-BP1 pathway and the resultant synthesis of secreted proteins including IL-6. Consequently, tumour growth and chemoresistance in nude mice xenografted with pancreatic cancer cells and CAFs, or with pieces of resected human PDACs, are reduced when chemotherapy (gemcitabine) is combined with SOM230 treatment. While gemcitabine alone has marginal effects, SOM230 is permissive to gemcitabine-induced cancer cell apoptosis and acts as an antifibrotic agent. We propose that selective inhibition of CAF protein synthesis with sst1-directed pharmacological compounds represents an anti-stromal-targeted therapy with promising chemosensitization potential. PMID:25834145

  9. Sulfonimidamide analogs of oncolytic sulfonylureas.

    PubMed

    Toth, J E; Grindey, G B; Ehlhardt, W J; Ray, J E; Boder, G B; Bewley, J R; Klingerman, K K; Gates, S B; Rinzel, S M; Schultz, R M; Weir, L C; Worzalla, J F

    1997-03-14

    A series of sulfonimidamide analogs of the oncolytic diarylsulfonylureas was synthesized and evaluated for (1) in vitro cytotoxicity against CEM cells, (2) in vivo antitumor activity against subaxillary implanted 6C3HED lymphosarcoma, and (3) metabolic breakdown to the o-sulfate of p-chloroaniline. The separated enantiomers of one sulfonimidamide analog displayed very different activities in the in vivo screening model. In general, several analogs demonstrated excellent growth inhibitory activity in the 6C3HED model when dosed orally or intraperitoneally. A correlative structure-activity relationship to the oncolytic sulfonylureas was not apparent.

  10. Evaluating countermeasures in spaceflight analogs.

    PubMed

    Ploutz-Snyder, Lori

    2016-04-15

    Countermeasures are defined as solutions to prevent the undesirable physiologic outcomes associated with spaceflight. Spaceflight analogs provide a valuable opportunity for the evaluation of countermeasures because they allow for the evaluation of more subjects, more experimental control, and are considerably less expensive than actual spaceflight. The various human analogs have differing strengths and weaknesses with respect to the development and evaluation of countermeasures. The human analogs are briefly reviewed with a focus on their suitability for countermeasure evaluation. Bed rest is the most commonly used analog for evaluating countermeasures. While countermeasures are typically developed to target one or maybe two particular physiologic issues, it is increasingly important to evaluate all of the organ systems to discern whether they might be unintended consequences on nontargeted tissues. In preparation for Mars exploration it will be necessary to fully integrate countermeasures to protect all organ systems. The synergistic and antagonistic effects of multiple countermeasures needs to be the focus of future work. PMID:26662054

  11. Introduction to Analog Field Testing

    NASA Video Gallery

    NASA tests systems and operational concepts in analog environments, which include locations underwater, in the arctic, on terrestrial impact craters, in the desert, and on the International Space S...

  12. Flight Analogs (Bed Rest Research)

    NASA Video Gallery

    Flight Analogs / Bed Rest Research Projects provide NASA with a ground based research platform to complement space research. By mimicking the conditions of weightlessness in the human body here on ...

  13. The Robustness of Acoustic Analogies

    NASA Technical Reports Server (NTRS)

    Freund, J. B.; Lele, S. K.; Wei, M.

    2004-01-01

    Acoustic analogies for the prediction of flow noise are exact rearrangements of the flow equations N(right arrow q) = 0 into a nominal sound source S(right arrow q) and sound propagation operator L such that L(right arrow q) = S(right arrow q). In practice, the sound source is typically modeled and the propagation operator inverted to make predictions. Since the rearrangement is exact, any sufficiently accurate model of the source will yield the correct sound, so other factors must determine the merits of any particular formulation. Using data from a two-dimensional mixing layer direct numerical simulation (DNS), we evaluate the robustness of two analogy formulations to different errors intentionally introduced into the source. The motivation is that since S can not be perfectly modeled, analogies that are less sensitive to errors in S are preferable. Our assessment is made within the framework of Goldstein's generalized acoustic analogy, in which different choices of a base flow used in constructing L give different sources S and thus different analogies. A uniform base flow yields a Lighthill-like analogy, which we evaluate against a formulation in which the base flow is the actual mean flow of the DNS. The more complex mean flow formulation is found to be significantly more robust to errors in the energetic turbulent fluctuations, but its advantage is less pronounced when errors are made in the smaller scales.

  14. All-optical analog comparator.

    PubMed

    Li, Pu; Yi, Xiaogang; Liu, Xianglian; Zhao, Dongliang; Zhao, Yongpeng; Wang, Yuncai

    2016-01-01

    An analog comparator is one of the core units in all-optical analog-to-digital conversion (AO-ADC) systems, which digitizes different amplitude levels into two levels of logical '1' or '0' by comparing with a defined decision threshold. Although various outstanding photonic ADC approaches have been reported, almost all of them necessitate an electrical comparator to carry out this binarization. The use of an electrical comparator is in contradiction to the aim of developing all-optical devices. In this work, we propose a new concept of an all-optical analog comparator and numerically demonstrate an implementation based on a quarter-wavelength-shifted distributed feedback laser diode (QWS DFB-LD) with multiple quantum well (MQW) structures. Our results show that the all-optical comparator is very well suited for true AO-ADCs, enabling the whole digital conversion from an analog optical signal (continuous-time signal or discrete pulse signal) to a binary representation totally in the optical domain. In particular, this all-optical analog comparator possesses a low threshold power (several mW), high extinction ratio (up to 40 dB), fast operation rate (of the order of tens of Gb/s) and a step-like transfer function.

  15. Crows spontaneously exhibit analogical reasoning.

    PubMed

    Smirnova, Anna; Zorina, Zoya; Obozova, Tanya; Wasserman, Edward

    2015-01-19

    Analogical reasoning is vital to advanced cognition and behavioral adaptation. Many theorists deem analogical thinking to be uniquely human and to be foundational to categorization, creative problem solving, and scientific discovery. Comparative psychologists have long been interested in the species generality of analogical reasoning, but they initially found it difficult to obtain empirical support for such thinking in nonhuman animals (for pioneering efforts, see [2, 3]). Researchers have since mustered considerable evidence and argument that relational matching-to-sample (RMTS) effectively captures the essence of analogy, in which the relevant logical arguments are presented visually. In RMTS, choice of test pair BB would be correct if the sample pair were AA, whereas choice of test pair EF would be correct if the sample pair were CD. Critically, no items in the correct test pair physically match items in the sample pair, thus demanding that only relational sameness or differentness is available to support accurate choice responding. Initial evidence suggested that only humans and apes can successfully learn RMTS with pairs of sample and test items; however, monkeys have subsequently done so. Here, we report that crows too exhibit relational matching behavior. Even more importantly, crows spontaneously display relational responding without ever having been trained on RMTS; they had only been trained on identity matching-to-sample (IMTS). Such robust and uninstructed relational matching behavior represents the most convincing evidence yet of analogical reasoning in a nonprimate species, as apes alone have spontaneously exhibited RMTS behavior after only IMTS training.

  16. All-optical analog comparator

    NASA Astrophysics Data System (ADS)

    Li, Pu; Yi, Xiaogang; Liu, Xianglian; Zhao, Dongliang; Zhao, Yongpeng; Wang, Yuncai

    2016-08-01

    An analog comparator is one of the core units in all-optical analog-to-digital conversion (AO-ADC) systems, which digitizes different amplitude levels into two levels of logical ‘1’ or ‘0’ by comparing with a defined decision threshold. Although various outstanding photonic ADC approaches have been reported, almost all of them necessitate an electrical comparator to carry out this binarization. The use of an electrical comparator is in contradiction to the aim of developing all-optical devices. In this work, we propose a new concept of an all-optical analog comparator and numerically demonstrate an implementation based on a quarter-wavelength-shifted distributed feedback laser diode (QWS DFB-LD) with multiple quantum well (MQW) structures. Our results show that the all-optical comparator is very well suited for true AO-ADCs, enabling the whole digital conversion from an analog optical signal (continuous-time signal or discrete pulse signal) to a binary representation totally in the optical domain. In particular, this all-optical analog comparator possesses a low threshold power (several mW), high extinction ratio (up to 40 dB), fast operation rate (of the order of tens of Gb/s) and a step-like transfer function.

  17. All-optical analog comparator

    PubMed Central

    Li, Pu; Yi, Xiaogang; Liu, Xianglian; Zhao, Dongliang; Zhao, Yongpeng; Wang, Yuncai

    2016-01-01

    An analog comparator is one of the core units in all-optical analog-to-digital conversion (AO-ADC) systems, which digitizes different amplitude levels into two levels of logical ‘1’ or ‘0’ by comparing with a defined decision threshold. Although various outstanding photonic ADC approaches have been reported, almost all of them necessitate an electrical comparator to carry out this binarization. The use of an electrical comparator is in contradiction to the aim of developing all-optical devices. In this work, we propose a new concept of an all-optical analog comparator and numerically demonstrate an implementation based on a quarter-wavelength-shifted distributed feedback laser diode (QWS DFB-LD) with multiple quantum well (MQW) structures. Our results show that the all-optical comparator is very well suited for true AO-ADCs, enabling the whole digital conversion from an analog optical signal (continuous-time signal or discrete pulse signal) to a binary representation totally in the optical domain. In particular, this all-optical analog comparator possesses a low threshold power (several mW), high extinction ratio (up to 40 dB), fast operation rate (of the order of tens of Gb/s) and a step-like transfer function. PMID:27550874

  18. All-optical analog comparator.

    PubMed

    Li, Pu; Yi, Xiaogang; Liu, Xianglian; Zhao, Dongliang; Zhao, Yongpeng; Wang, Yuncai

    2016-01-01

    An analog comparator is one of the core units in all-optical analog-to-digital conversion (AO-ADC) systems, which digitizes different amplitude levels into two levels of logical '1' or '0' by comparing with a defined decision threshold. Although various outstanding photonic ADC approaches have been reported, almost all of them necessitate an electrical comparator to carry out this binarization. The use of an electrical comparator is in contradiction to the aim of developing all-optical devices. In this work, we propose a new concept of an all-optical analog comparator and numerically demonstrate an implementation based on a quarter-wavelength-shifted distributed feedback laser diode (QWS DFB-LD) with multiple quantum well (MQW) structures. Our results show that the all-optical comparator is very well suited for true AO-ADCs, enabling the whole digital conversion from an analog optical signal (continuous-time signal or discrete pulse signal) to a binary representation totally in the optical domain. In particular, this all-optical analog comparator possesses a low threshold power (several mW), high extinction ratio (up to 40 dB), fast operation rate (of the order of tens of Gb/s) and a step-like transfer function. PMID:27550874

  19. Crows spontaneously exhibit analogical reasoning.

    PubMed

    Smirnova, Anna; Zorina, Zoya; Obozova, Tanya; Wasserman, Edward

    2015-01-19

    Analogical reasoning is vital to advanced cognition and behavioral adaptation. Many theorists deem analogical thinking to be uniquely human and to be foundational to categorization, creative problem solving, and scientific discovery. Comparative psychologists have long been interested in the species generality of analogical reasoning, but they initially found it difficult to obtain empirical support for such thinking in nonhuman animals (for pioneering efforts, see [2, 3]). Researchers have since mustered considerable evidence and argument that relational matching-to-sample (RMTS) effectively captures the essence of analogy, in which the relevant logical arguments are presented visually. In RMTS, choice of test pair BB would be correct if the sample pair were AA, whereas choice of test pair EF would be correct if the sample pair were CD. Critically, no items in the correct test pair physically match items in the sample pair, thus demanding that only relational sameness or differentness is available to support accurate choice responding. Initial evidence suggested that only humans and apes can successfully learn RMTS with pairs of sample and test items; however, monkeys have subsequently done so. Here, we report that crows too exhibit relational matching behavior. Even more importantly, crows spontaneously display relational responding without ever having been trained on RMTS; they had only been trained on identity matching-to-sample (IMTS). Such robust and uninstructed relational matching behavior represents the most convincing evidence yet of analogical reasoning in a nonprimate species, as apes alone have spontaneously exhibited RMTS behavior after only IMTS training. PMID:25532894

  20. Are polymers suitable rock analogs?

    NASA Astrophysics Data System (ADS)

    ten Grotenhuis, Saskia M.; Piazolo, Sandra; Pakula, T.; Passchier, Cees W.; Bons, Paul D.

    2002-05-01

    To evaluate if a polymer is suitable for analog modeling, it is essential to know the rheological properties of the material. Polymers used in analog modeling exhibit a complex rheological behavior; only part of which has been taken into account in most modeling studies. The mechanical behavior is strongly dependent on strain rate and temperature, and is characterized by specific dependencies of the storage and loss moduli, related to the elasticity and viscosity, on the deformation rate (frequency). We have measured the storage and loss moduli at a broad range of strain rates and strains, using an oscillatory parallel-disk rheometer. Investigated materials are polydimethylsiloxane (PDMS), mixtures of PDMS and BaSO 4 (filler), Rhodorsil Gomme and mixtures of Rhodorsil Gomme and plastilina, all commonly used in analog experiments. Our measurements show that the rheological properties of mixtures of plastilina and Rhodorsil Gomme depend on its deformation history. Therefore, these mixtures are problematic for analog modeling. For mixtures of PDMS and BaSO 4, the significance of the elastic component increases with increasing filler content, and accordingly, these mixtures have a limited application for modeling of viscous deformation. Pure PDMS and Rhodorsil Gomme exhibit Newtonian flow behavior at strain rates commonly used in analog modeling.

  1. Natural analogs for Yucca Mountain

    SciTech Connect

    Murphy, W.M.

    1995-11-01

    High-level radioactive waste in the US, spent fuels from commercial reactors and nuclear materials generated by defense activities, will remain potentially hazardous for thousands of years. Demonstrable long-term stability of certain geologic and geochemical systems motivates and sustains the concept that high-level waste can be safely isolated in geologic repositories for requisite periods of time. Each geologic repository is unique in its properties and performance with reguard to isolation of nuclear wastes. Studies of processes analogous to waste-form alteration and radioelement transport in environments analogous to Yucca Mountain are being conducted at two sites, described in this article to illustrate uses of natural analog data: the Nopal I uranium deposit in the Sierra Pena Blanca, Mexico, and the Akrotiri archaeological site on the island of Santorini, Greece.

  2. Test Wiseness and Analogy Test Performance

    ERIC Educational Resources Information Center

    Moore, James C.

    1971-01-01

    Subjects received self instruction on how to approach analogy questions. Instruction was directed toward knowledge of the general format of analogy questions in standarized tests and the 15 types of relationships commonly asked for in analogy questions. An analogies post-test showed a significant effect for the group. (Author)

  3. Analogies in Science and Science Teaching

    ERIC Educational Resources Information Center

    Brown, Simon; Salter, Susan

    2010-01-01

    Analogies are often used in science, but students may not appreciate their significance, and so the analogies can be misunderstood or discounted. For this reason, educationalists often express concern about the use of analogies in teaching. Given the important place of analogies in the discourse of science, it is necessary that students are…

  4. Multilateral Collaborations in Analog Research

    NASA Technical Reports Server (NTRS)

    Cromwell, R. l.

    2016-01-01

    International collaborations in studies utilizing ground-based space flight analogs are an effective means for answering research questions common to participating agencies. These collaborations bring together worldwide experts to solve important space research questions. By collaborating unnecessary duplication of science is reduced, and the efficiency of analog use is improved. These studies also share resources among agencies for cost effective solutions to study implementation. Recently, NASA has engaged in collaborations with international partners at a variety of analog sites. The NASA Human Exploration Research Analog (HERA) is currently hosting investigator studies from NASA and from the German Space Agency (DLR). These isolation studies will answer questions in the areas of team cohesion, sleep and circadian rhythms, and neurobehavioral correlates to function. Planning for the next HERA campaign is underway as proposal selections are being made from the International Life Sciences Research Announcement (ILSRA). Studies selected from the ILSRA will be conducted across 4 HERA missions in 2017. NASA is planning collaborative studies with DLR at the :envihab facility in Cologne, Germany. Investigations were recently selected to study the effects of 0.5% CO2 exposure over 30 days of bed rest. These studies will help to determine the fidelity of this ground-based analog for studying the visual impairment intracranial pressure syndrome. NASA is also planning a multilateral collaboration at :envihab with DLR and the European Space Agency (ESA) to examine artificial gravity as a countermeasure to mitigate the effects of 60 days of bed rest. NASA is also considering collaborations with the Russian Institute for Biomedical Problems (IBMP) in studies that will utilize their Ground-based Experimental Facility (NEK). The NEK is comprised of 4 interconnected modules and a Martian surface simulator. This isolation analog can support 3 -10 crew members for long duration

  5. Terrestrial analogs for space exploration habitation systems

    NASA Technical Reports Server (NTRS)

    Campbell, Paul D.; Brown, Jeri W.

    1992-01-01

    The Space Exploration Initiative (SEI) can use early earth-based analogs to simulate many aspects of space flight missions and system operation. These analogs can thus provide information supporting future missions to the moon and to Mars. A study was performed to investigate the potential of terrestrial analogs in simulating human space exploration missions. The study resulted in preliminary requirements and concepts for analog habitation systems, and further study in this area is necessary for SEI terrestrial analog development.

  6. Analog Input Data Acquisition Software

    NASA Technical Reports Server (NTRS)

    Arens, Ellen

    2009-01-01

    DAQ Master Software allows users to easily set up a system to monitor up to five analog input channels and save the data after acquisition. This program was written in LabVIEW 8.0, and requires the LabVIEW runtime engine 8.0 to run the executable.

  7. Geometrical Analogies in Mathematics Lessons

    ERIC Educational Resources Information Center

    Eid, Wolfram

    2007-01-01

    A typical form of thinking to approach problem solutions humanly is thinking in analogous structures. Therefore school, especially mathematical lessons should help to form and to develop corresponding heuristic abilities of the pupils. In the contribution, a summary of possibilities of mathematics lessons regarding this shall particularly be…

  8. Analogy of the Cell Project

    ERIC Educational Resources Information Center

    Science Scope, 2005

    2005-01-01

    In this project, students compare the makeup of a cell to an everyday working unit or system. They create a three-dimensional object that represents their analogy. For example, students could create a car motor or manufacturing plant. (Of course, this is totally hand-created by them, so it can be a homemade re-creation of a system, not an actual…

  9. Analog Simulation of a Laser.

    ERIC Educational Resources Information Center

    Kessler, Gary

    1982-01-01

    Presents an analog simulation of laser properties (finding time evolution of the intensity of a ruby laser pulse) which serves as the basis of a three-four hour laboratory experiment. Includes programs for solution to rate equations of a three-level laser and production of a giant pulse in a ruby laser. (Author/SK)

  10. Algicidal Activity of Stilbene Analogs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As part of our continuing search for natural product and natural product-based compounds for the control of off-flavor in catfish, a total of twenty nine stilbene analogs were synthesized and evaluated for algicidal activity against the 2-methylisoborneol (MIB)-producing cyanobacterium Oscillatoria ...

  11. Paper Analogies Enhance Biology Teaching.

    ERIC Educational Resources Information Center

    Stencel, John E.

    1997-01-01

    Describes how to use paper analogies as models to illustrate various concepts in biology, human anatomy, and physiology classes. Models include biochemical paper models, protein papergrams, a paper model of early brain development, and a 3-D paper model of a eukaryotic cell. (AIM)

  12. Mathematical Analogy and Metaphorical Insight

    ERIC Educational Resources Information Center

    Zwicky, Jan

    2010-01-01

    How are we to understand the power of certain literary metaphors? The author argues that the apprehension of good metaphors is importantly similar to the apprehension of fruitful mathematical analogies: both involve a structural realignment of vision. The author then explores consequences of this claim, drawing conceptually significant parallels…

  13. Understanding & Teaching Genetics Using Analogies

    ERIC Educational Resources Information Center

    Woody, Scott; Himelblau, Ed

    2013-01-01

    We present a collection of analogies that are intended to help students better understand the foreign and often nuanced vocabulary of the genetics curriculum. Why is it called the "wild type"? What is the difference between a locus, a gene, and an allele? What is the functional (versus a rule-based) distinction between dominant and…

  14. International Alligator Rivers Analog Project

    SciTech Connect

    Bichard, G.F.

    1988-01-01

    The Australian Nuclear Science and Technology Organization (ANSTO), the Japan Atomic Energy Research Institute, the Swedish Nuclear Power Inspectorate, the U.K. Department of the Environment, the US Nuclear Regulatory Commission (NRC), and the Power Reactor and Nuclear Fuel Development Corporation of Japan are participating under the aegis of the Nuclear Energy Agency in the International Alligator Rivers Analog Project. The project has a duration of 3 yr, starting in 1988. The project has grown out of a research program on uranium ore bodies as analogs of high-level waste (HLW) repositories undertaken by ANSTO supported by the NRC. A primary objective of the project is to develop an approach to radionuclide transport model validation that may be used by the participants to support assessments of the safety of radioactive waste repositories. The approach involves integrating mathematical and physical modeling with hydrological and geochemical field and laboratory investigations of the analog site. The Koongarra uranium ore body has been chosen as the analog site because it has a secondary ore body that has formed over the past million years as a result of leaching by groundwater flowing through fractures in the primary ore body.

  15. Electrical analog to projectile motion

    NASA Astrophysics Data System (ADS)

    Vondracek, Mark

    1998-04-01

    This article describes an electrical analog to traditional projectile problems given in high school and introductory college classes. It also discusses the importance of stressing the understanding of physical laws and principles to students, and that the physics behind a problem is more important than being able to memorize and use various equations.

  16. Analogy between Thermodynamics and Mechanics.

    ERIC Educational Resources Information Center

    Peterson, Mark A.

    1979-01-01

    Establishes and illustrates a formal analogy between the motion of a particle and the "motion" of the equilibrium state of a homogeneous system in a quasistatic process. The purpose is to show that there is a much larger set of natural coordinate transformations in thermodynamics. (GA)

  17. Bayesian Analogy with Relational Transformations

    ERIC Educational Resources Information Center

    Lu, Hongjing; Chen, Dawn; Holyoak, Keith J.

    2012-01-01

    How can humans acquire relational representations that enable analogical inference and other forms of high-level reasoning? Using comparative relations as a model domain, we explore the possibility that bottom-up learning mechanisms applied to objects coded as feature vectors can yield representations of relations sufficient to solve analogy…

  18. Battery hydrometer with analog output

    SciTech Connect

    Patis, B.L.

    1982-09-21

    There is disclosed a battery hydrometer for providing an analog electrical signal having a magnitude related to the specific gravity of a battery electrolyte. The hydrometer includes a source of radiation for providing a detectable beam of radiation and a piston member arranged to be submerged within the electrolyte and to intercept and modulate the beam of radiation in response to the specific gravity of the electrolyte. The piston member is suspended within the electrolyte by a spring which exerts a compressive force upon the piston member against which the electrolyte must act. The hydrometer further includes a radiation detector aligned with the radiation source for providing an analog electrical signal having a magnitude responsive to the modulated beam of radiation.

  19. Analog Nonvolatile Computer Memory Circuits

    NASA Technical Reports Server (NTRS)

    MacLeod, Todd

    2007-01-01

    In nonvolatile random-access memory (RAM) circuits of a proposed type, digital data would be stored in analog form in ferroelectric field-effect transistors (FFETs). This type of memory circuit would offer advantages over prior volatile and nonvolatile types: In a conventional complementary metal oxide/semiconductor static RAM, six transistors must be used to store one bit, and storage is volatile in that data are lost when power is turned off. In a conventional dynamic RAM, three transistors must be used to store one bit, and the stored bit must be refreshed every few milliseconds. In contrast, in a RAM according to the proposal, data would be retained when power was turned off, each memory cell would contain only two FFETs, and the cell could store multiple bits (the exact number of bits depending on the specific design). Conventional flash memory circuits afford nonvolatile storage, but they operate at reading and writing times of the order of thousands of conventional computer memory reading and writing times and, hence, are suitable for use only as off-line storage devices. In addition, flash memories cease to function after limited numbers of writing cycles. The proposed memory circuits would not be subject to either of these limitations. Prior developmental nonvolatile ferroelectric memories are limited to one bit per cell, whereas, as stated above, the proposed memories would not be so limited. The design of a memory circuit according to the proposal must reflect the fact that FFET storage is only partly nonvolatile, in that the signal stored in an FFET decays gradually over time. (Retention times of some advanced FFETs exceed ten years.) Instead of storing a single bit of data as either a positively or negatively saturated state in a ferroelectric device, each memory cell according to the proposal would store two values. The two FFETs in each cell would be denoted the storage FFET and the control FFET. The storage FFET would store an analog signal value

  20. Classical Analog to Entanglement Reversibility

    NASA Astrophysics Data System (ADS)

    Chitambar, Eric; Fortescue, Ben; Hsieh, Min-Hsiu

    2015-08-01

    In this Letter we study the problem of secrecy reversibility. This asks when two honest parties can distill secret bits from some tripartite distribution pX Y Z and transform secret bits back into pX Y Z at equal rates using local operation and public communication. This is the classical analog to the well-studied problem of reversibly concentrating and diluting entanglement in a quantum state. We identify the structure of distributions possessing reversible secrecy when one of the honest parties holds a binary distribution, and it is possible that all reversible distributions have this form. These distributions are more general than what is obtained by simply constructing a classical analog to the family of quantum states known to have reversible entanglement. An indispensable tool used in our analysis is a conditional form of the Gács-Körner common information.

  1. Thermal analog device reduces machining errors

    NASA Technical Reports Server (NTRS)

    Mcclure, E. R.

    1972-01-01

    Thermal analog devices predict thermal expansion and contraction of machine structures subjected to various heat inputs. Analog devices correct positioning of machine tools to compensate for distortion of machine frame.

  2. Simple Electronic Analog of a Josephson Junction.

    ERIC Educational Resources Information Center

    Henry, R. W.; And Others

    1981-01-01

    Demonstrates that an electronic Josephson junction analog constructed from three integrated circuits plus an external reference oscillator can exhibit many of the circuit phenomena of a real Josephson junction. Includes computer and other applications of the analog. (Author/SK)

  3. Basic Electricity--a Novel Analogy.

    ERIC Educational Resources Information Center

    Grant, Richard

    1996-01-01

    Uses the analogy of water flow to introduce concepts in basic electricity. Presents a demonstration that uses this analogy to help students grasp the relationship between current, voltage, and resistance. (JRH)

  4. Hegel, Analogy, and Extraterrestrial Life

    NASA Astrophysics Data System (ADS)

    Ross, Joseph T.

    Georg Wilhelm Friedrich Hegel rejected the possibility of life outside of the Earth, according to several scholars of extraterrestrial life. Their position is that the solar system and specifically the planet Earth is the unique place in the cosmos where life, intelligence, and rationality can be. The present study offers a very different interpretation of Hegel's statements about the place of life on Earth by suggesting that, although Hegel did not believe that there were other solar systems where rationality is present, he did in fact suggest that planets in general, not the Earth exclusively, have life and possibly also intelligent inhabitants. Analogical syllogisms are superficial, according to Hegel, insofar as they try to conclude that there is life on the Moon even though there is no evidence of water or air on that body. Similar analogical arguments for life on the Sun made by Johann Elert Bode and William Herschel were considered by Hegel to be equally superficial. Analogical arguments were also used by astronomers and philosophers to suggest that life could be found on other planets in our solar system. Hegel offers no critique of analogical arguments for life on other planets, and in fact Hegel believed that life would be found on other planets. Planets, after all, have meteorological processes and therefore are "living" according to his philosophical account, unlike the Moon, Sun, and comets. Whereas William Herschel was already finding great similarities between the Sun and the stars and had extended these similarities to the property of having planets or being themselves inhabitable worlds, Hegel rejected this analogy. The Sun and stars have some properties in common, but for Hegel one cannot conclude from these similarities to the necessity that stars have planets. Hegel's arguments against the presence of life in the solar system were not directed against other planets, but rather against the Sun and Moon, both of which he said have a different

  5. Science Teachers' Analogical Reasoning

    ERIC Educational Resources Information Center

    Mozzer, Nilmara Braga; Justi, Rosária

    2013-01-01

    Analogies can play a relevant role in students' learning. However, for the effective use of analogies, teachers should not only have a well-prepared repertoire of validated analogies, which could serve as bridges between the students' prior knowledge and the scientific knowledge they desire them to understand, but also know how to…

  6. Visual homing in analog hardware.

    PubMed

    Möller, R

    1999-10-01

    Insects of several species rely on visual landmarks for returning to important locations in their environment. The "average landmark vector model" is a parsimonious model which reproduces some aspects of the visual homing behavior of bees and ants. To gain insights in the structure and complexity of the neural apparatus that might underly the navigational capabilities of these animals, the average landmark vector model was implemented in analog hardware and used to control a mobile robot. The experiments demonstrate that the apparently complex task of visual homing might be realized by simple and mostly peripheral neural circuits in insect brains.

  7. Classical analog of quantum phase

    SciTech Connect

    Ord, G.N.

    1992-07-01

    A modified version of the Feynman relativistic chessboard model (FCM) is investigated in which the paths involved are spirals in the space-time. Portions of the paths in which the particle`s proper time is reversed are interpreted in terms of antiparticles. With this intepretation the particle-antiparticle field produced by such trajectories provides a classical analog of the phase associated with particle paths in the unmodified FCM. It is shwon that in the nonrelativistic limit the resulting kernel is the correct Dirac propagator and that particle-antiparticle symmetry is in this case responsible for quantum interference. 7 refs., 3 figs.

  8. Analog computing by Brewster effect.

    PubMed

    Youssefi, Amir; Zangeneh-Nejad, Farzad; Abdollahramezani, Sajjad; Khavasi, Amin

    2016-08-01

    Optical computing has emerged as a promising candidate for real-time and parallel continuous data processing. Motivated by recent progresses in metamaterial-based analog computing [Science343, 160 (2014)SCIEAS0036-807510.1126/science.1242818], we theoretically investigate the realization of two-dimensional complex mathematical operations using rotated configurations, recently reported in [Opt. Lett.39, 1278 (2014)OPLEDP0146-959210.1364/OL.39.001278]. Breaking the reflection symmetry, such configurations could realize both even and odd Green's functions associated with spatial operators. Based on such an appealing theory and by using the Brewster effect, we demonstrate realization of a first-order differentiator. Such an efficient wave-based computation method not only circumvents the major potential drawbacks of metamaterials, but also offers the most compact possible device compared to conventional bulky lens-based optical signal and data processors.

  9. QCD analogy for quantum gravity

    NASA Astrophysics Data System (ADS)

    Holdom, Bob; Ren, Jing

    2016-06-01

    Quadratic gravity presents us with a renormalizable, asymptotically free theory of quantum gravity. When its couplings grow strong at some scale, as in QCD, then this strong scale sets the Planck mass. QCD has a gluon that does not appear in the physical spectrum. Quadratic gravity has a spin-2 ghost that we conjecture does not appear in the physical spectrum. We discuss how the QCD analogy leads to this conjecture and to the possible emergence of general relativity. Certain aspects of the QCD path integral and its measure are also similar for quadratic gravity. With the addition of the Einstein-Hilbert term, quadratic gravity has a dimensionful parameter that seems to control a quantum phase transition and the size of a mass gap in the strong phase.

  10. The Young Solar Analogs Project

    NASA Astrophysics Data System (ADS)

    Gray, Richard O.; Saken, J. M.; Corbally, C. J.; Seeds, M. F.; Morrison, S. S.

    2012-01-01

    We are carrying out a long-term project of measuring chromospheric activity and brightness variations in 31 young solar analogs (YSAs) using the Dark Sky Observatory (DSO -- Appalachian State University) 32-inch telescope and the G/M spectrograph. These YSAs are solar-type (spectral types F8 - K2) stars with ages ranging from 0.3 - 1.5 Gyr. The goal of this project is to gain better understanding of the magnetic activity of the early Sun, and especially how that activity may have impacted the development of life on the Earth. This project will also yield insights into the space environments experienced by young Earth analogs. We are currently in our 5th year of obtaining Ca II K & H chromospheric flux measurements, and are beginning to see signs of long-term activity cycles in a number of our stars. In addition, rotational modulation of the chromospheric fluxes is detectable in our data, and we have determined rotational periods for many of our stars. Short timescale increases in the K & H fluxes have been observed in a number of our stars; these events may be related to stellar flares. VATTSpec, a new moderate-resolution spectrograph on the 1.8-m Vatican Telescope in Arizona, has recently become involved with the project. This spectrograph will increase our ability to detect short-term changes in stellar activity on timescales of hours to minutes. We have been monitoring the program stars for one year in a multi-band photometric system consisting of Stromgren-v, and Johnson B, V, and R filters. We will soon add a narrow-band H-alpha filter to the system. Photometry is being carried out with a small piggy-back telescope on the 32-inch, but a robotic photometric telescope is currently being installed at DSO for this purpose. This project is supported by the National Science Foundation.

  11. Children's use of analogy during collaborative reasoning.

    PubMed

    Lin, Tzu-Jung; Anderson, Richard C; Hummel, John E; Jadallah, May; Miller, Brian W; Nguyen-Jahiel, Kim; Morris, Joshua A; Kuo, Li-Jen; Kim, Il-Hee; Wu, Xiaoying; Dong, Ting

    2012-01-01

    This microgenetic study examined social influences on children's development of analogical reasoning during peer-led small-group discussions of stories about controversial issues. A total of 277 analogies were identified among 7,215 child turns for speaking during 54 discussions from 18 discussion groups in 6 fourth-grade classrooms (N = 120; age M=10.0, SD=0.6). Use of analogy was found to spread among the children in discussion groups and occur at an accelerating rate, primarily because of the increasing use of novel analogies. Relational analogies with shared surface features triggered purely relational analogies during the next 2 speaking turns, showing a trend of relational shift. These results provide distinctive new evidence for the importance of social interaction in an aspect of cognitive development. PMID:22670717

  12. An emergent approach to analogical inference

    NASA Astrophysics Data System (ADS)

    Thibodeau, Paul H.; Flusberg, Stephen J.; Glick, Jeremy J.; Sternberg, Daniel A.

    2013-03-01

    In recent years, a growing number of researchers have proposed that analogy is a core component of human cognition. According to the dominant theoretical viewpoint, analogical reasoning requires a specific suite of cognitive machinery, including explicitly coded symbolic representations and a mapping or binding mechanism that operates over these representations. Here we offer an alternative approach: we find that analogical inference can emerge naturally and spontaneously from a relatively simple, error-driven learning mechanism without the need to posit any additional analogy-specific machinery. The results also parallel findings from the developmental literature on analogy, demonstrating a shift from an initial reliance on surface feature similarity to the use of relational similarity later in training. Variants of the model allow us to consider and rule out alternative accounts of its performance. We conclude by discussing how these findings can potentially refine our understanding of the processes that are required to perform analogical inference.

  13. Classical Analogs of a Diatomic Chain

    SciTech Connect

    Gutierrez, L.; Diaz-de-Anda, A.; Mendez-Sanchez, R. A.; Morales, A.; Flores, J.; Monsivais, G.

    2010-12-21

    Using one dimensional rods with different configurations classical analogs of quantum mechanical systems frequently used in solid state physics can be obtained. Among this analogs we have recently discussed locally periodic rods which lead to band spectra; the effect of a topological defect, and the Wannier Stark ladders. In this paper, we present an elastic analog of the diatomic chain and show how the acoustical and optical bands emerge, as well of the nature of the wave amplitudes.

  14. Real World: Analog Testing in Extreme Environments

    NASA Video Gallery

    See how NASA uses analog testing to simulate space exploration. Explore extreme environments like the Aquarius underwater laboratory in Key Largo, Florida. Find out how scientists use mathematical ...

  15. Expert analogy use in a naturalistic setting

    PubMed Central

    Kretz, Donald R.; Krawczyk, Daniel C.

    2014-01-01

    The use of analogy is an important component of human cognition. The type of analogy we produce and communicate depends heavily on a number of factors, such as the setting, the level of domain expertise present, and the speaker's goal or intent. In this observational study, we recorded economics experts during scientific discussion and examined the categorical distance and structural depth of the analogies they produced. We also sought to characterize the purpose of the analogies that were generated. Our results supported previous conclusions about the infrequency of superficial similarity in subject-generated analogs, but also showed that distance and depth characteristics were more evenly balanced than in previous observational studies. This finding was likely due to the nature of the goals of the participants, as well as the broader nature of their expertise. An analysis of analogical purpose indicated that the generation of concrete source examples of more general target concepts was most prevalent. We also noted frequent instances of analogies intended to form visual images of source concepts. Other common purposes for analogies were the addition of colorful speech, inclusion (i.e., subsumption) of a target into a source concept, or differentiation between source and target concepts. We found no association between depth and either of the other two characteristics, but our findings suggest a relationship between purpose and distance; i.e., that visual imagery typically entailed an outside-domain source whereas exemplification was most frequently accomplished using within-domain analogies. Overall, we observed a rich and diverse set of spontaneously produced analogical comparisons. The high degree of expertise within the observed group along with the richly comparative nature of the economics discipline likely contributed to this analogical abundance. PMID:25505437

  16. Novel Analog For Muscle Deconditioning

    NASA Technical Reports Server (NTRS)

    Ploutz-Snyder, Lori; Ryder, Jeff; Buxton, Roxanne; Redd, Elizabeth; Scott-Pandorf, Melissa; Hackney, Kyle; Fiedler, James; Bloomberg, Jacob

    2010-01-01

    Existing models of muscle deconditioning are cumbersome and expensive (ex: bedrest). We propose a new model utilizing a weighted suit to manipulate strength, power or endurance (function) relative to body weight (BW). Methods: 20 subjects performed 7 occupational astronaut tasks while wearing a suit weighted with 0-120% of BW. Models of the full relationship between muscle function/BW and task completion time were developed using fractional polynomial regression and verified by the addition of pre- and post-flight astronaut performance data using the same tasks. Spline regression was used to identify muscle function thresholds below which task performance was impaired. Results: Thresholds of performance decline were identified for each task. Seated egress & walk (most difficult task) showed thresholds of: leg press (LP) isometric peak force/BW of 18 N/kg, LP power/BW of 18 W/kg, LP work/ BW of 79 J/kg, knee extension (KE) isokinetic/BW of 6 Nm/Kg and KE torque/BW of 1.9 Nm/kg. Conclusions: Laboratory manipulation of strength / BW has promise as an appropriate analog for spaceflight-induced loss of muscle function for predicting occupational task performance and establishing operationally relevant exercise targets.

  17. Novel Analog For Muscle Deconditioning

    NASA Technical Reports Server (NTRS)

    Ploutz-Snyder, Lori; Ryder, Jeff; Buxton, Roxanne; Redd. Elizabeth; Scott-Pandorf, Melissa; Hackney, Kyle; Fiedler, James; Ploutz-Snyder, Robert; Bloomberg, Jacob

    2011-01-01

    Existing models (such as bed rest) of muscle deconditioning are cumbersome and expensive. We propose a new model utilizing a weighted suit to manipulate strength, power, or endurance (function) relative to body weight (BW). Methods: 20 subjects performed 7 occupational astronaut tasks while wearing a suit weighted with 0-120% of BW. Models of the full relationship between muscle function/BW and task completion time were developed using fractional polynomial regression and verified by the addition of pre-and postflightastronaut performance data for the same tasks. Splineregression was used to identify muscle function thresholds below which task performance was impaired. Results: Thresholds of performance decline were identified for each task. Seated egress & walk (most difficult task) showed thresholds of leg press (LP) isometric peak force/BW of 18 N/kg, LP power/BW of 18 W/kg, LP work/BW of 79 J/kg, isokineticknee extension (KE)/BW of 6 Nm/kg, and KE torque/BW of 1.9 Nm/kg.Conclusions: Laboratory manipulation of relative strength has promise as an appropriate analog for spaceflight-induced loss of muscle function, for predicting occupational task performance and establishing operationally relevant strength thresholds.

  18. Solar System Analog; WMO Statement

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    Scientists searching for extra-solar planets have discovered the closest known analog to our own Solar System. A planet with a mass about twice that of Jupiter is in a near-circular orbit of the star HD70642, a team of astronomers from Australia, the United Kingdom, and the United States announced on 3 July at a conference in Paris on extra-solar planets.The planet measures about three-fifths the size of Jupiter, circles its star about every six years, and is in an orbit equivalent to being about halfway between Mars and Jupiter if it were located in our Solar System, according to the astronomers. The star is about 90 light years away from Earth in the constellation Puppis.Public concern about a spate of well-publicized, extreme weather events around the world this year has prompted the World Meteorological Organization to issue a statement that, as global temperatures continues to rise due to climate change, the number and intensity of extreme events might increase. The July 2 statement is based on scientific assessments by the Intergovernmental Panel on Climate Change and others, rather than on any new studies, according to Ken Davidson, director orf WMO's World Climate Program Department. The statement cites record high termperatures so far this summer in southern France and in Switzerland, an abnormally high number of tornadoes in the U.S. in May, and particularly heavy rains from tropical cyclones in Sri Lanka.

  19. The Pennies-as-Electrons Analogy

    ERIC Educational Resources Information Center

    Ashmann, Scott

    2009-01-01

    Everyday experiences familiarize students with the ways in which electricity is used, but often the underlying concepts remain a mystery. Teachers often use analogies to help students relate the flow of electrons to other common systems, but many times these analogies are incomplete and lead to more student misconceptions. However, the "pass the…

  20. Antibacterial and Antibiofilm Activities of Makaluvamine Analogs

    PubMed Central

    Nijampatnam, Bhavitavya; Nadkarni, Dwayaja H.; Wu, Hui; Velu, Sadanandan E.

    2015-01-01

    Streptococcus mutans is a key etiological agent in the formation of dental caries. The major virulence factor is its ability to form biofilms. Inhibition of S. mutans biofilms offers therapeutic prospects for the treatment and the prevention of dental caries. In this study, 14 analogs of makaluvamine, a marine alkaloid, were evaluated for their antibacterial activity against S. mutans and for their ability to inhibit S. mutans biofilm formation. All analogs contained the tricyclic pyrroloiminoquinone core of makaluvamines. The structural variations of the analogs are on the amino substituents at the 7-position of the ring and the inclusion of a tosyl group on the pyrrole ring N of the makaluvamine core. The makaluvamine analogs displayed biofilm inhibition with IC50 values ranging from 0.4 μM to 88 μM. Further, the observed bactericidal activity of the majority of the analogs was found to be consistent with the anti-biofilm activity, leading to the conclusion that the anti-biofilm activity of these analogs stems from their ability to kill S. mutans. However, three of the most potent N-tosyl analogs showed biofilm IC50 values at least an order of magnitude lower than that of bactericidal activity, indicating that the biofilm activity of these analogs is more selective and perhaps independent of bactericidal activity. PMID:25767719

  1. Piperazine-based nucleic acid analogs

    DOEpatents

    Schmidt, Jurgen; Silks, Louis A.; Michalczyk, Ryszard

    2005-01-11

    A novel nucleoside analog is disclosed which comprises a piperazine ring in the place of the ring ribose or deoxyribose sugar. Monomers utilizing a broad variety of nucleobases are disclosed, as well as oligomers comprising the monomers disclosed herein linked by a variety of linkages, including amide, phosphonamide, and sulfonamide linkages. A method of synthesizing the nucleoside analogs is also disclosed.

  2. An Analog Computer for Electronic Engineering Education

    ERIC Educational Resources Information Center

    Fitch, A. L.; Iu, H. H. C.; Lu, D. D. C.

    2011-01-01

    This paper describes a compact analog computer and proposes its use in electronic engineering teaching laboratories to develop student understanding of applications in analog electronics, electronic components, engineering mathematics, control engineering, safe laboratory and workshop practices, circuit construction, testing, and maintenance. The…

  3. A Mechanical Analogy for the Photoelectric Effect

    ERIC Educational Resources Information Center

    Kovacevic, Milan S.; Djordjevich, Alexandar

    2006-01-01

    Analogy is a potent tool in the teacher's repertoire. It has been particularly well recognized in the teaching of science. However, careful planning is required for its effective application to prevent documented drawbacks when analogies are stretched too far. Befitting the occasion of the World Year of Physics commemorating Albert Einstein's 1905…

  4. Analogical Processes and College Developmental Reading

    ERIC Educational Resources Information Center

    Paulson, Eric J.

    2014-01-01

    Although a solid body of research concerning the role of analogies in reading processes has emerged at a variety of age groups and reading proficiencies, few of those studies have focused on analogy use by readers enrolled in college developmental reading courses. The current study explores whether 232 students enrolled in mandatory (by placement…

  5. Children's Use of Analogy during Collaborative Reasoning

    ERIC Educational Resources Information Center

    Lin, Tzu-Jung; Anderson, Richard C.; Hummel, John E.; Jadallah, May; Miller, Brian W.; Nguyen-Jahiel, Kim; Morris, Joshua A.; Kuo, Li-Jen; Kim, Il-Hee; Wu, Xiaoying; Dong, Ting

    2012-01-01

    This microgenetic study examined social influences on children's development of analogical reasoning during peer-led small-group discussions of stories about controversial issues. A total of 277 analogies were identified among 7,215 child turns for speaking during 54 discussions from 18 discussion groups in 6 fourth-grade classrooms (N = 120; age…

  6. Young Children's Analogical Reasoning in Science Domains

    ERIC Educational Resources Information Center

    Haglund, Jesper; Jeppsson, Fredrik; Andersson, Johanna

    2012-01-01

    This exploratory study in a classroom setting investigates first graders' (age 7-8 years, N = 25) ability to perform analogical reasoning and create their own analogies for two irreversible natural phenomena: mixing and heat transfer. We found that the children who contributed actively to a full-class discussion were consistently successful at…

  7. The Structure of Analogical Models in Science.

    ERIC Educational Resources Information Center

    Gentner, Dedre

    Analogical models can be powerful aids to reasoning, as when light is explained in terms of water waves; or they can be misleading, as when chemical processes are thought of in terms of life processes such as putrefaction. This paper proposes a structural characterization of good science analogy using a theoretical approach in which complex…

  8. Mathematical Analogs and the Teaching of Fractions.

    ERIC Educational Resources Information Center

    Charles, Kathy; Nason, Rod; Cooper, Tom

    The literature has noted that some mathematical analogs are more effective than others for the teaching of fractions. This study aimed to evaluate the efficacy of seven mathematical analogs commonly used in the teaching of the partitive quotient fraction construct. A sample of twelve purposively selected Year Three children were presented with…

  9. 38 CFR 4.20 - Analogous ratings.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Analogous ratings. 4.20 Section 4.20 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS SCHEDULE FOR RATING DISABILITIES General Policy in Rating § 4.20 Analogous ratings. When an unlisted condition is encountered...

  10. Rotanone analogs: method of preparation and use

    DOEpatents

    VanBrocklin, Henry F; O& #x27; Neil, James P; Gibbs, Andrew R; Erathodiyil, Nandanan

    2013-10-08

    The present invention provides rotenone analogs and methods of making and using them. Labeled with single photon and positron emitting isotopes, the rotenone analogs of the present invention are useful in, for example, clinical imaging applications as tracers to measure cardiac blood flow and detect regions of ischemia.

  11. Use of Analogy in Computer Language Acquisition.

    ERIC Educational Resources Information Center

    Pohl, Heidi L.; Nutter, Jane Terry

    1985-01-01

    Subjects in a study of analogic reasoning use in learning a computer language read text describing an invented LISP dialect and then solved problems and described language constructs. Five of six factors studied indicating use of analogy with a familiar computer language showed statistically significant results, supporting the hypothesis.…

  12. An Analog Earth Climate Model

    NASA Astrophysics Data System (ADS)

    Varekamp, J. C.

    2010-12-01

    The earth climate is broadly governed by the radiative power of the sun as well as the heat retention and convective cooling of the atmosphere. I have constructed an analog earth model for an undergraduate climate class that simulates mean climate using these three parameters. The ‘earth’ is a hollow, black, bronze sphere (4 cm diameter) mounted on a thin insulated rod, and illuminated by two opposite optic fibers, with light focused on the sphere by a set of lenses. The sphere is encased in a large double-walled aluminum cylinder (34 cm diameter by 26 cm high) with separate water cooling jackets at the top, bottom, and sides. The cylinder can be filled with a gas of choice at a variety of pressures or can be run in vacuum. The exterior is cladded with insulation, and the temperature of the sphere, atmosphere and walls is monitored with thermocouples. The temperature and waterflow of the three cooling jackets can be monitored to establish the energy output of the whole system; the energy input is the energy yield of the two optic fibers. A small IR transmissive lens at the top provides the opportunity to hook up the fiber of a hyper spectrometer to monitor the emission spectrum of the black ‘earth’ sphere. A pressure gauge and gas inlet-outlet system for flushing of the cell completes it. The heat yield of the cooling water at the top is the sum of the radiative and convective components, whereas the bottom jacket only carries off the radiative heat of the sphere. Undergraduate E&ES students at Wesleyan University have run experiments with dry air, pure CO2, N2 and Ar at 1 atmosphere, and a low vacuum run was accomplished to calibrate the energy input. For each experiment, the lights are flipped on, the temperature acquisition routine is activated, and the sphere starts to warm up until an equilibrium temperature has been reached. The lights are then flipped off and the cooling sequence towards ambient is registered. The energy input is constant for a given

  13. Investigation of Celestial Solid Analogs

    NASA Technical Reports Server (NTRS)

    Sievers, A. J.

    2003-01-01

    Our far infrared studies of both hydrophobic and hydrophilic aerogel grains have demonstrated that the mm and sub-mm wave absorption produced by the fundamental two level systems (TLS) mechanism represents a more significant contribution for these open grain structures than for bulk amorphous silicate grains. We found that the region with the anomalous temperature dependence of the spectral index due to the TLS excitations can extend in a fluffy material up to 80 per cm, which is well beyond its typical upper limit for bulk glasses. Currently there is no theoretical explanation for this surprising result. The effects of reduced dimensionality on the optical properties of carbonaceous grains have been studied with a systematic investigation of carbon aerogels. This spectroscopic approach has permitted a more reliable determination of the single grain mass normalized absorption coefficient based on the experimentally determined characteristics of the fluffy material rather than on first principles calculations involving the bulk properties of the substance. Our finding is that the electrical connectivity of the material is the main factor affecting its far infrared absorption coefficient. Another one of the main constituents of the interstellar dust, amorphous ice, has been investigated in the mm-wave region both in the high (HDA) and low (LDA) density amorphous phases and as a function of impurities. We found that doping either phase with ionic (LiCl) or molecular (methanol) impurities decreases the difference in the mm-wave absorption coefficient between the HDA and LDA ice phases so that the HDA spectrum can be used as an analog for impure ice absorption in the far infrared spectral region.

  14. [Cell analogs of viral proteins].

    PubMed

    Blinov, V M; Gaĭsler, V; Krasnov, G S; Shargunov, A V; Shurdov, M A; Zverev, V V

    2014-01-01

    Horizontal transfer of genes between viruses and their hosts played an important role in the evolution of various eukaryotes including contemporary mammals as well as the pathogens themselves. Elements of viruses of various types can be found in the genome of animals. Endogenous retroviral elements composing up to 8% of human genome length not only determine its high flexibility and rapid adaptation potential. Many of virus genes such as Fv1, Lv1, Lv2 being analogues of capsid and other proteins determine effective suppression of viral replication after cell penetration by the causative agent. Introduction of these elements into genome of a wide variety of animals from fish to primates could have taken place against the background of global natural cataclysms of viral origin. Integration of retrovirus genes coding surface glycoproteins with immunosuppressing domains into genetic apparatus of animals served as an impetus to the development of viviparity and spread ofplacental mammals. Their cell analogs syncytins perform a dual function: take direct part in the formation of syncytiotrophoblast layer of placenta and ensure tolerance of immune system of mother to embryo. The acquisition of cell genes by viruses also played an important role in their evolution: various interleukins and other modulators of immune response introduced into viral genome from cell genetic apparatus became one of the most important factors of pathogenicity of a wide variety of causative agents including poxviruses, cytomegalovirus, Epstein-Barr virus and many others. Evolutionary pathways of the virus and host are thus inseparable from each other, and character of one of these directions is largely dictated by the vector of another. PMID:25051706

  15. Fostering Multilateral Involvement in Analog Research

    NASA Technical Reports Server (NTRS)

    Cromwell, Ronita L.

    2015-01-01

    International collaboration in space flight research is an effective means for conducting investigations and utilizing limited resources to the fullest extent. Through these multilateral collaborations mutual research questions can be investigated and resources contributed by each international partner to maximize the scientific benefits to all parties. Recently the international partners embraced this approach to initiate collaborations in ground-based space flight analog environments. In 2011, the International Analog Research Working Group was established, and later named the International Human Space Flight Analog Research Coordination Group (HANA). Among the goals of this working group are to 1) establish a framework to coordinate research campaigns, as appropriate, to minimize duplication of effort and enhance synergy; 2) define what analogs are best to use for collaborative interests; and 3) facilitate interaction between discipline experts in order to have the full benefit of international expertise. To accomplish these goals, HANA is currently engaged in developing international research campaigns in ground-based analogs. Plans are being made for an international solicitation for proposals to address research of common interest to all international partners. This solicitation with identify an analog environment that will best accommodate the types of investigations requested. Once selected, studies will be integrated into a campaign and implemented at the analog site. Through these combined efforts, research beneficial to all partners will be conducted efficiently to further address human risks of space exploration.

  16. Analogies: Explanatory Tools in Web-Based Science Instruction

    ERIC Educational Resources Information Center

    Glynn, Shawn M.; Taasoobshirazi, Gita; Fowler, Shawn

    2007-01-01

    This article helps designers of Web-based science instruction construct analogies that are as effective as those used in classrooms by exemplary science teachers. First, the authors explain what analogies are, how analogies foster learning, and what form analogies should take. Second, they discuss science teachers' use of analogies. Third, they…

  17. Programmable Analog-To-Digital Converter

    NASA Technical Reports Server (NTRS)

    Kist, Edward H., Jr.

    1993-01-01

    High-speed analog-to-digital converter with programmable voltage steps that can be changed during operation. Allows concentration of converter resolution over specific portion of waveform. Particularly useful in digitizing wind-shear radar and lidar return signals, in digital oscilloscopes, and other applications in which desirable to increase digital resolution over specific area of waveform while accepting lower resolution over rest of waveform. Effective increase in dynamic range achieved without increase in number of analog-to-digital converter bits. Enabling faster analog-to-digital conversion.

  18. Analog detection for cavity lifetime spectroscopy

    DOEpatents

    Zare, Richard N.; Harb, Charles C.; Paldus, Barbara A.; Spence, Thomas G.

    2001-05-15

    An analog detection system for determining a ring-down rate or decay rate 1/.tau. of an exponentially decaying ring-down beam issuing from a lifetime or ring-down cavity during a ring-down phase. Alternatively, the analog detection system determines a build-up rate of an exponentially growing beam issuing from the cavity during a ring-up phase. The analog system can be employed in continuous wave cavity ring-down spectroscopy (CW CRDS) and pulsed CRDS (P CRDS) arrangements utilizing any type of ring-down cavity including ring-cavities and linear cavities.

  19. Analog detection for cavity lifetime spectroscopy

    DOEpatents

    Zare, Richard N.; Harb, Charles C.; Paldus, Barbara A.; Spence, Thomas G.

    2003-01-01

    An analog detection system for determining a ring-down rate or decay rate 1/.tau. of an exponentially decaying ring-down beam issuing from a lifetime or ring-down cavity during a ring-down phase. Alternatively, the analog detection system determines a build-up rate of an exponentially growing beam issuing from the cavity during a ring-up phase. The analog system can be employed in continuous wave cavity ring-down spectroscopy (CW CRDS) and pulsed CRDS (P CRDS) arrangements utilizing any type of ring-down cavity including ring-cavities and linear cavities.

  20. Comparative conformational analysis of peptide T analogs

    NASA Astrophysics Data System (ADS)

    Akverdieva, Gulnare; Godjayev, Niftali; Akyuz, Sevim

    2009-01-01

    A series of peptide T analogs were investigated within the molecular mechanics framework. In order to determine the role of the aminoacid residues in spatial formation of peptide T the conformational peculiarities of the glycine-substituted analogs were investigated. The conformational profiles of some biologically tested analogs of this peptide were determined independently. The received data permit to assess the active form of this peptide. It is characterized by β-turn at the C-terminal physiologically active pentapeptide fragment of peptide molecule. The received results are important for the investigation of the structure-activity relationship and may be used at design of a rigid-molecule drug against HIV.

  1. Analog Computer Laboratory with Biological Examples.

    ERIC Educational Resources Information Center

    Strebel, Donald E.

    1979-01-01

    The use of biological examples in teaching applications of the analog computer is discussed and several examples from mathematical ecology, enzyme kinetics, and tracer dynamics are described. (Author/GA)

  2. An Electrical Analog Computer for Poets

    ERIC Educational Resources Information Center

    Bruels, Mark C.

    1972-01-01

    Nonphysics majors are presented with a direct current experiment beyond Ohms law and series and parallel laws. This involves construction of an analog computer from common rheostats and student-assembled voltmeters. (Author/TS)

  3. Synthesis of sulfonate analogs of bile acids.

    PubMed

    Kihira, K; Mikami, T; Ikawa, S; Okamoto, A; Yoshii, M; Miki, S; Mosbach, E H; Hoshita, T

    1992-04-01

    Sulfonate analogs of C23 and C24 bile acids were synthesized from norcholic, norchenodeoxycholic, norursodeoxycholic, nordeoxycholic, norhyodeoxycholic, cholic, deoxycholic, hyodeoxycholic, and lithocholic acids. The principal reactions used were (1) reduction of the bile acids with NaBH4 to the corresponding bile alcohols, (2) selective tosylation of the terminal hydroxyl group, (3) iodination of the tosyl esters with NaI, and (4) treatment of the iodides with Na2SO3 to form the sulfonate analogs of the bile acids. The sulfonate analogs showed polarity similar to that of taurine-conjugated bile acids on thin-layer chromatography. The carbon 13 nuclear magnetic resonance spectral data for the sulfonate analogs were tabulated.

  4. NASA Now: Exploring Asteroids: An Analog Mission

    NASA Video Gallery

    NASA’s Extreme Environment Mission Operations, or NEEMO, project lead Bill Todd describes this analog mission and how aquanauts living and working in an undersea habitat are helping NASA prepare ...

  5. An Electronic Analog of the Diffraction Grating.

    ERIC Educational Resources Information Center

    MacLeod, A. M.

    1978-01-01

    Gives an outline description of electronic circuitry which is analogous to the optical diffraction grating or to crystals used in the Bragg reflection of X-rays or electron waves, and explains how to use it. (Author/GA)

  6. Computer Analogies: Teaching Molecular Biology and Ecology.

    ERIC Educational Resources Information Center

    Rice, Stanley; McArthur, John

    2002-01-01

    Suggests that computer science analogies can aid the understanding of gene expression, including the storage of genetic information on chromosomes. Presents a matrix of biology and computer science concepts. (DDR)

  7. The Analog (Computer) As a Physiology Adjunct.

    ERIC Educational Resources Information Center

    Stewart, Peter A.

    1979-01-01

    Defines and discusses the analog computer and its use in a physiology laboratory. Includes two examples: (1) The Respiratory Control Function and (2) CO-Two Control in the Respiratory System. Presents diagrams and mathematical models. (MA)

  8. Optical analog-to-digital converter

    DOEpatents

    Vawter, G. Allen; Raring, James; Skogen, Erik J.

    2009-07-21

    An optical analog-to-digital converter (ADC) is disclosed which converts an input optical analog signal to an output optical digital signal at a sampling rate defined by a sampling optical signal. Each bit of the digital representation is separately determined using an optical waveguide interferometer and an optical thresholding element. The interferometer uses the optical analog signal and the sampling optical signal to generate a sinusoidally-varying output signal using cross-phase-modulation (XPM) or a photocurrent generated from the optical analog signal. The sinusoidally-varying output signal is then digitized by the thresholding element, which includes a saturable absorber or at least one semiconductor optical amplifier, to form the optical digital signal which can be output either in parallel or serially.

  9. AMiBA WIDEBAND ANALOG CORRELATOR

    SciTech Connect

    Li, Chao-Te; Kubo, Derek Y.; Lin, Kai-Yang; Chen, Ming-Tang; Ho, P. T. P.; Chen, Chung-Cheng; Han, Chih-Chiang; Oshiro, Peter; Martin-Cocher, Pierre; Chang, Chia-Hao; Chang, Shu-Hao; Altamirano, Pablo; Jiang, Homin; Wilson, Warwick; Chiueh, Tzi-Dar; Lien, Chun-Hsien; Wang, Huei; Wei, Ray-Ming; Yang, Chia-Hsiang; Peterson, Jeffrey B.

    2010-06-10

    A wideband analog correlator has been constructed for the Yuan-Tseh Lee Array for Microwave Background Anisotropy. Lag correlators using analog multipliers provide large bandwidth and moderate frequency resolution. Broadband intermediate frequency distribution, back-end signal processing, and control are described. Operating conditions for optimum sensitivity and linearity are discussed. From observations, a large effective bandwidth of around 10 GHz has been shown to provide sufficient sensitivity for detecting cosmic microwave background variations.

  10. ANALOG-TO-DIGITAL DATA CONVERTER

    DOEpatents

    Rodgers, G.W.; Althouse, J.E.; Anderson, D.P.; Bussey, G.R.; Minnear, L.H.

    1960-09-01

    Electrical apparatus is described, particularly useful in telemetry work, for converting analog signals into electrical pulses and recording them. An electronic editor commands the taking of signal readings at a frequency which varies according to linearity of the analog signal being converted. Readings of information signals are recorded, along with time base readings and serial numbering, if desired, on magnetic tape and the latter may be used to operate a computer or the like. Magnetic tape data may be transferred to punched cards.

  11. Analog environments in space human factors

    NASA Technical Reports Server (NTRS)

    Connors, Mary M.

    1992-01-01

    An account is given of what has been learned from space analog environments, which mimic such significant features of space as isolation, confinement, risk, and deprivation; emphasis is placed on the especially successful environments constituted by extended submarine research, undersea habitats, and Antarctic station wintering. Attention is also given to the advantages and limitations of the use of analog environments for space human factors research, and possibilities for such research efforts' management.

  12. AMiBA Wideband Analog Correlator

    NASA Astrophysics Data System (ADS)

    Li, Chao-Te; Kubo, Derek Y.; Wilson, Warwick; Lin, Kai-Yang; Chen, Ming-Tang; Ho, P. T. P.; Chen, Chung-Cheng; Han, Chih-Chiang; Oshiro, Peter; Martin-Cocher, Pierre; Chang, Chia-Hao; Chang, Shu-Hao; Altamirano, Pablo; Jiang, Homin; Chiueh, Tzi-Dar; Lien, Chun-Hsien; Wang, Huei; Wei, Ray-Ming; Yang, Chia-Hsiang; Peterson, Jeffrey B.; Chang, Su-Wei; Huang, Yau-De; Hwang, Yuh-Jing; Kesteven, Michael; Koch, Patrick; Liu, Guo-Chin; Nishioka, Hiroaki; Umetsu, Keiichi; Wei, Tashun; Proty Wu, Jiun-Huei

    2010-06-01

    A wideband analog correlator has been constructed for the Yuan-Tseh Lee Array for Microwave Background Anisotropy. Lag correlators using analog multipliers provide large bandwidth and moderate frequency resolution. Broadband intermediate frequency distribution, back-end signal processing, and control are described. Operating conditions for optimum sensitivity and linearity are discussed. From observations, a large effective bandwidth of around 10 GHz has been shown to provide sufficient sensitivity for detecting cosmic microwave background variations.

  13. Analog hardware for learning neural networks

    NASA Technical Reports Server (NTRS)

    Eberhardt, Silvio P. (Inventor)

    1991-01-01

    This is a recurrent or feedforward analog neural network processor having a multi-level neuron array and a synaptic matrix for storing weighted analog values of synaptic connection strengths which is characterized by temporarily changing one connection strength at a time to determine its effect on system output relative to the desired target. That connection strength is then adjusted based on the effect, whereby the processor is taught the correct response to training examples connection by connection.

  14. Synthetic heparin-binding growth factor analogs

    DOEpatents

    Pena, Louis A.; Zamora, Paul; Lin, Xinhua; Glass, John D.

    2007-01-23

    The invention provides synthetic heparin-binding growth factor analogs having at least one peptide chain that binds a heparin-binding growth factor receptor, covalently bound to a hydrophobic linker, which is in turn covalently bound to a non-signaling peptide that includes a heparin-binding domain. The synthetic heparin-binding growth factor analogs are useful as soluble biologics or as surface coatings for medical devices.

  15. Analog modelling of obduction processes

    NASA Astrophysics Data System (ADS)

    Agard, P.; Zuo, X.; Funiciello, F.; Bellahsen, N.; Faccenna, C.; Savva, D.

    2012-04-01

    Obduction corresponds to one of plate tectonics oddities, whereby dense, oceanic rocks (ophiolites) are presumably 'thrust' on top of light, continental ones, as for the short-lived, almost synchronous Peri-Arabic obduction (which took place along thousands of km from Turkey to Oman in c. 5-10 Ma). Analog modelling experiments were performed to study the mechanisms of obduction initiation and test various triggering hypotheses (i.e., plate acceleration, slab hitting the 660 km discontinuity, ridge subduction; Agard et al., 2007). The experimental setup comprises (1) an upper mantle, modelled as a low-viscosity transparent Newtonian glucose syrup filling a rigid Plexiglas tank and (2) high-viscosity silicone plates (Rhodrosil Gomme with PDMS iron fillers to reproduce densities of continental or oceanic plates), located at the centre of the tank above the syrup to simulate the subducting and the overriding plates - and avoid friction on the sides of the tank. Convergence is simulated by pushing on a piston at one end of the model with velocities comparable to those of plate tectonics (i.e., in the range 1-10 cm/yr). The reference set-up includes, from one end to the other (~60 cm): (i) the piston, (ii) a continental margin containing a transition zone to the adjacent oceanic plate, (iii) a weakness zone with variable resistance and dip (W), (iv) an oceanic plate - with or without a spreading ridge, (v) a subduction zone (S) dipping away from the piston and (vi) an upper, active continental margin, below which the oceanic plate is being subducted at the start of the experiment (as is known to have been the case in Oman). Several configurations were tested and over thirty different parametric tests were performed. Special emphasis was placed on comparing different types of weakness zone (W) and the extent of mechanical coupling across them, particularly when plates were accelerated. Displacements, together with along-strike and across-strike internal deformation in all

  16. Development of analogical problem-solving skill.

    PubMed

    Holyoak, K J; Junn, E N; Billman, D O

    1984-12-01

    3 experiments were performed to assess children's ability to solve a problem by analogy to a superficially dissimilar situation. Preschoolers and fifth and sixth graders were asked to solve a problem that allowed multiple solutions. Some subjects were first read a story that included an analogous problem and its solution. When the mapping between the relations involved in the corresponding solutions was relatively simple, and the corresponding instruments were perceptually and functionally similar, even preschoolers were able to use the analogy to derive a solution to the transfer problem (Experiment 1). Furthermore, salient similarity of the instruments was neither sufficient (Experiment 2) nor necessary (Experiment 3) for success by preschool subjects. When the story analog mapped well onto the transfer problem, 4-year-olds were often able to generate a solution that required transformation of an object with little perceptual or semantic similarity to the instrument used in the base analog (Experiment 3). The older children used analogies in a manner qualitatively similar to that observed in comparable studies with adults (Experiment 1), whereas the younger children exhibited different limitations.

  17. Optical domain analog to digital conversion methods and apparatus

    DOEpatents

    Vawter, Gregory A

    2014-05-13

    Methods and apparatus for optical analog to digital conversion are disclosed. An optical signal is converted by mapping the optical analog signal onto a wavelength modulated optical beam, passing the mapped beam through interferometers to generate analog bit representation signals, and converting the analog bit representation signals into an optical digital signal. A photodiode receives an optical analog signal, a wavelength modulated laser coupled to the photodiode maps the optical analog signal to a wavelength modulated optical beam, interferometers produce an analog bit representation signal from the mapped wavelength modulated optical beam, and sample and threshold circuits corresponding to the interferometers produce a digital bit signal from the analog bit representation signal.

  18. Analogy, higher order thinking, and education.

    PubMed

    Richland, Lindsey Engle; Simms, Nina

    2015-01-01

    Analogical reasoning, the ability to understand phenomena as systems of structured relationships that can be aligned, compared, and mapped together, plays a fundamental role in the technology rich, increasingly globalized educational climate of the 21st century. Flexible, conceptual thinking is prioritized in this view of education, and schools are emphasizing 'higher order thinking', rather than memorization of a cannon of key topics. The lack of a cognitively grounded definition for higher order thinking, however, has led to a field of research and practice with little coherence across domains or connection to the large body of cognitive science research on thinking. We review literature on analogy and disciplinary higher order thinking to propose that relational reasoning can be productively considered the cognitive underpinning of higher order thinking. We highlight the utility of this framework for developing insights into practice through a review of mathematics, science, and history educational contexts. In these disciplines, analogy is essential to developing expert-like disciplinary knowledge in which concepts are understood to be systems of relationships that can be connected and flexibly manipulated. At the same time, analogies in education require explicit support to ensure that learners notice the relevance of relational thinking, have adequate processing resources available to mentally hold and manipulate relations, and are able to recognize both the similarities and differences when drawing analogies between systems of relationships.

  19. An analog silicon retina with multichip configuration.

    PubMed

    Kameda, Seiji; Yagi, Tetsuya

    2006-01-01

    The neuromorphic silicon retina is a novel analog very large scale integrated circuit that emulates the structure and the function of the retinal neuronal circuit. We fabricated a neuromorphic silicon retina, in which sample/hold circuits were embedded to generate fluctuation-suppressed outputs in the previous study [1]. The applications of this silicon retina, however, are limited because of a low spatial resolution and computational variability. In this paper, we have fabricated a multichip silicon retina in which the functional network circuits are divided into two chips: the photoreceptor network chip (P chip) and the horizontal cell network chip (H chip). The output images of the P chip are transferred to the H chip with analog voltages through the line-parallel transfer bus. The sample/hold circuits embedded in the P and H chips compensate for the pattern noise generated on the circuits, including the analog communication pathway. Using the multichip silicon retina together with an off-chip differential amplifier, spatial filtering of the image with an odd- and an even-symmetric orientation selective receptive fields was carried out in real time. The analog data transfer method in the present multichip silicon retina is useful to design analog neuromorphic multichip systems that mimic the hierarchical structure of neuronal networks in the visual system.

  20. Analog forecasting with dynamics-adapted kernels

    NASA Astrophysics Data System (ADS)

    Zhao, Zhizhen; Giannakis, Dimitrios

    2016-09-01

    Analog forecasting is a nonparametric technique introduced by Lorenz in 1969 which predicts the evolution of states of a dynamical system (or observables defined on the states) by following the evolution of the sample in a historical record of observations which most closely resembles the current initial data. Here, we introduce a suite of forecasting methods which improve traditional analog forecasting by combining ideas from kernel methods developed in harmonic analysis and machine learning and state-space reconstruction for dynamical systems. A key ingredient of our approach is to replace single-analog forecasting with weighted ensembles of analogs constructed using local similarity kernels. The kernels used here employ a number of dynamics-dependent features designed to improve forecast skill, including Takens’ delay-coordinate maps (to recover information in the initial data lost through partial observations) and a directional dependence on the dynamical vector field generating the data. Mathematically, our approach is closely related to kernel methods for out-of-sample extension of functions, and we discuss alternative strategies based on the Nyström method and the multiscale Laplacian pyramids technique. We illustrate these techniques in applications to forecasting in a low-order deterministic model for atmospheric dynamics with chaotic metastability, and interannual-scale forecasting in the North Pacific sector of a comprehensive climate model. We find that forecasts based on kernel-weighted ensembles have significantly higher skill than the conventional approach following a single analog.

  1. An analog integrated-circuit vocal tract.

    PubMed

    Keng Hoong Wee; Turicchia, L; Sarpeshkar, R

    2008-12-01

    We present the first experimental integrated-circuit vocal tract by mapping fluid volume velocity to current, fluid pressure to voltage, and linear and nonlinear mechanical impedances to linear and nonlinear electrical impedances. The 275 muW analog vocal tract chip includes a 16-stage cascade of two-port pi-elements that forms a tunable transmission line, electronically variable impedances, and a current source as the glottal source. A nonlinear resistor models laminar and turbulent flow in the vocal tract. The measured SNR at the output of the analog vocal tract is 64, 66, and 63 dB for the first three formant resonances of a vocal tract with uniform cross-sectional area. The analog vocal tract can be used with auditory processors in a feedback speech locked loop-analogous to a phase locked loop-to implement speech recognition that is potentially robust in noise. Our use of a physiological model of the human vocal tract enables the analog vocal tract chip to synthesize speech signals of interest, using articulatory parameters that are intrinsically compact and linearly interpolatable. PMID:23853134

  2. Analogy, higher order thinking, and education.

    PubMed

    Richland, Lindsey Engle; Simms, Nina

    2015-01-01

    Analogical reasoning, the ability to understand phenomena as systems of structured relationships that can be aligned, compared, and mapped together, plays a fundamental role in the technology rich, increasingly globalized educational climate of the 21st century. Flexible, conceptual thinking is prioritized in this view of education, and schools are emphasizing 'higher order thinking', rather than memorization of a cannon of key topics. The lack of a cognitively grounded definition for higher order thinking, however, has led to a field of research and practice with little coherence across domains or connection to the large body of cognitive science research on thinking. We review literature on analogy and disciplinary higher order thinking to propose that relational reasoning can be productively considered the cognitive underpinning of higher order thinking. We highlight the utility of this framework for developing insights into practice through a review of mathematics, science, and history educational contexts. In these disciplines, analogy is essential to developing expert-like disciplinary knowledge in which concepts are understood to be systems of relationships that can be connected and flexibly manipulated. At the same time, analogies in education require explicit support to ensure that learners notice the relevance of relational thinking, have adequate processing resources available to mentally hold and manipulate relations, and are able to recognize both the similarities and differences when drawing analogies between systems of relationships. PMID:26263071

  3. NaturAnalogs for the Unsaturated Zone

    SciTech Connect

    A. Simmons; A. Unger; M. Murrell

    2000-03-08

    The purpose of this Analysis/Model Report (AMR) is to document natural and anthropogenic (human-induced) analog sites and processes that are applicable to flow and transport processes expected to occur at the potential Yucca Mountain repository in order to build increased confidence in modeling processes of Unsaturated Zone (UZ) flow and transport. This AMR was prepared in accordance with ''AMR Development Plan for U0135, Natural Analogs for the UZ'' (CRWMS 1999a). Knowledge from analog sites and processes is used as corroborating information to test and build confidence in flow and transport models of Yucca Mountain, Nevada. This AMR supports the Unsaturated Zone (UZ) Flow and Transport Process Model Report (PMR) and the Yucca Mountain Site Description. The objectives of this AMR are to test and build confidence in the representation of UZ processes in numerical models utilized in the UZ Flow and Transport Model. This is accomplished by: (1) applying data from Boxy Canyon, Idaho in simulations of UZ flow using the same methodologies incorporated in the Yucca Mountain UZ Flow and Transport Model to assess the fracture-matrix interaction conceptual model; (2) Providing a preliminary basis for analysis of radionuclide transport at Pena Blanca, Mexico as an analog of radionuclide transport at Yucca Mountain; and (3) Synthesizing existing information from natural analog studies to provide corroborating evidence for representation of ambient and thermally coupled UZ flow and transport processes in the UZ Model.

  4. Not All Analogies Are Created Equal: Associative and Categorical Analogy Processing following Brain Damage

    ERIC Educational Resources Information Center

    Schmidt, Gwenda L.; Cardillo, Eileen R.; Kranjec, Alexander; Lehet, Matthew; Widick, Page; Chatterjee, Anjan

    2012-01-01

    Current research on analogy processing assumes that different conceptual relations are treated similarly. However, just as words and concepts are related in distinct ways, different kinds of analogies may employ distinct types of relationships. An important distinction in how words are related is the difference between associative (dog-bone) and…

  5. Students' Pre- and Post-Teaching Analogical Reasoning when They Draw Their Analogies

    ERIC Educational Resources Information Center

    Mozzer, Nilmara Braga; Justi, Rosaria

    2012-01-01

    Analogies are parts of human thought. From them, we can acquire new knowledge or change that which already exists in our cognitive structure. In this sense, understanding the analogical reasoning process becomes an essential condition to understand how we learn. Despite the importance of such an understanding, there is no general agreement in…

  6. Gravitoelectromagnetic analogy based on tidal tensors

    SciTech Connect

    Costa, L. Filipe O.; Herdeiro, Carlos A. R.

    2008-07-15

    We propose a new approach to a physical analogy between general relativity and electromagnetism, based on tidal tensors of both theories. Using this approach we write a covariant form for the gravitational analogues of the Maxwell equations, which makes transparent both the similarities and key differences between the two interactions. The following realizations of the analogy are given. The first one matches linearized gravitational tidal tensors to exact electromagnetic tidal tensors in Minkowski spacetime. The second one matches exact magnetic gravitational tidal tensors for ultrastationary metrics to exact magnetic tidal tensors of electromagnetism in curved spaces. In the third we show that our approach leads to a two-step exact derivation of Papapetrou's equation describing the force exerted on a spinning test particle. Analogous scalar invariants built from tidal tensors of both theories are also discussed.

  7. Analogy-Enhanced Instruction: Effects on Reasoning Skills in Science

    ERIC Educational Resources Information Center

    Remigio, Krisette B.; Yangco, Rosanelia T.; Espinosa, Allen A.

    2014-01-01

    The study examined the reasoning skills of first year high school students after learning general science concepts through analogies. Two intact heterogeneous sections were randomly assigned to Analogy-Enhanced Instruction (AEI) group and Non Analogy-Enhanced (NAEI) group. Various analogies were incorporated in the lessons of the AEI group for…

  8. The Importance of Explicitly Mapping Instructional Analogies in Science Education

    ERIC Educational Resources Information Center

    Asay, Loretta Johnson

    2013-01-01

    Analogies are ubiquitous during instruction in science classrooms, yet research about the effectiveness of using analogies has produced mixed results. An aspect seldom studied is a model of instruction when using analogies. The few existing models for instruction with analogies have not often been examined quantitatively. The Teaching With…

  9. Space flight nutrition research: platforms and analogs

    NASA Technical Reports Server (NTRS)

    Smith, Scott M.; Uchakin, Peter N.; Tobin, Brian W.

    2002-01-01

    Conducting research during actual or simulated weightlessness is a challenging endeavor, where even the simplest activities may present significant challenges. This article reviews some of the potential obstacles associated with performing research during space flight and offers brief descriptions of current and previous space research platforms and ground-based analogs, including those for human, animal, and cell-based research. This review is intended to highlight the main issues of space flight research analogs and leave the specifics for each physiologic system for the other papers in this section.

  10. Analog graphic display method and apparatus

    DOEpatents

    Kronberg, J.W.

    1991-08-13

    Disclosed are an apparatus and method for using an output device such as an LED to show the approximate analog level of a variable electrical signal wherein a modulating AC waveform is superimposed either on the signal or a reference voltage, both of which are then fed to a comparator which drives the output device. Said device flashes at a constant perceptible rate with a duty cycle which varies in response to variations in the level of the input signal. The human eye perceives these variations in duty cycle as analogous to variations in the level of the input signal. 21 figures.

  11. Associative Pattern Recognition In Analog VLSI Circuits

    NASA Technical Reports Server (NTRS)

    Tawel, Raoul

    1995-01-01

    Winner-take-all circuit selects best-match stored pattern. Prototype cascadable very-large-scale integrated (VLSI) circuit chips built and tested to demonstrate concept of electronic associative pattern recognition. Based on low-power, sub-threshold analog complementary oxide/semiconductor (CMOS) VLSI circuitry, each chip can store 128 sets (vectors) of 16 analog values (vector components), vectors representing known patterns as diverse as spectra, histograms, graphs, or brightnesses of pixels in images. Chips exploit parallel nature of vector quantization architecture to implement highly parallel processing in relatively simple computational cells. Through collective action, cells classify input pattern in fraction of microsecond while consuming power of few microwatts.

  12. Parallel Analog-to-Digital Image Processor

    NASA Technical Reports Server (NTRS)

    Lokerson, D. C.

    1987-01-01

    Proposed integrated-circuit network of many identical units convert analog outputs of imaging arrays of x-ray or infrared detectors to digital outputs. Converter located near imaging detectors, within cryogenic detector package. Because converter output digital, lends itself well to multiplexing and to postprocessing for correction of gain and offset errors peculiar to each picture element and its sampling and conversion circuits. Analog-to-digital image processor is massively parallel system for processing data from array of photodetectors. System built as compact integrated circuit located near local plane. Buffer amplifier for each picture element has different offset.

  13. Solid-phase synthesis of prenylcysteine analogs

    PubMed Central

    Donelson, James L.; Hodges-Loaiza, Heather B.; Henriksen, Brian S.; Hrycyna, Christine A.

    2009-01-01

    Prenylcysteine derivatives are of interest for a variety of different biological reasons, including probing the CaaX protein processing pathway. A solid-phase synthesis protocol for the preparation of prenylcysteines using 2-chlorotrityl chloride resin as a solid support has been developed. A series of novel amide-modified farnesylcysteine analogs were synthesized in both high purity and yield under mild conditions. The farnesylcysteine analogs were evaluated using human isoprenylcysteine carboxyl methyltransferase (Icmt) as a biological target, and several new inhibitors, one with significantly enhanced potency, were identified. PMID:19320430

  14. Landauer bound for analog computing systems.

    PubMed

    Diamantini, M Cristina; Gammaitoni, Luca; Trugenberger, Carlo A

    2016-07-01

    By establishing a relation between information erasure and continuous phase transitions we generalize the Landauer bound to analog computing systems. The entropy production per degree of freedom during erasure of an analog variable (reset to standard value) is given by the logarithm of the configurational volume measured in units of its minimal quantum. As a consequence, every computation has to be carried on with a finite number of bits and infinite precision is forbidden by the fundamental laws of physics, since it would require an infinite amount of energy. PMID:27575108

  15. Landauer bound for analog computing systems

    NASA Astrophysics Data System (ADS)

    Diamantini, M. Cristina; Gammaitoni, Luca; Trugenberger, Carlo A.

    2016-07-01

    By establishing a relation between information erasure and continuous phase transitions we generalize the Landauer bound to analog computing systems. The entropy production per degree of freedom during erasure of an analog variable (reset to standard value) is given by the logarithm of the configurational volume measured in units of its minimal quantum. As a consequence, every computation has to be carried on with a finite number of bits and infinite precision is forbidden by the fundamental laws of physics, since it would require an infinite amount of energy.

  16. Synthetic heparin-binding factor analogs

    DOEpatents

    Pena, Louis A.; Zamora, Paul O.; Lin, Xinhua; Glass, John D.

    2010-04-20

    The invention provides synthetic heparin-binding growth factor analogs having at least one peptide chain, and preferably two peptide chains branched from a dipeptide branch moiety composed of two trifunctional amino acid residues, which peptide chain or chains bind a heparin-binding growth factor receptor and are covalently bound to a non-signaling peptide that includes a heparin-binding domain, preferably by a linker, which may be a hydrophobic linker. The synthetic heparin-binding growth factor analogs are useful as pharmaceutical agents, soluble biologics or as surface coatings for medical devices.

  17. Analog graphic display method and apparatus

    DOEpatents

    Kronberg, James W.

    1991-01-01

    An apparatus and method for using an output device such as an LED to show the approximate analog level of a variable electrical signal wherein a modulating AC waveform is superimposed either on the signal or a reference voltage, both of which are then fed to a comparator which drives the output device. Said device flashes at a constant perceptible rate with a duty cycle which varies in response to variations in the level of the input signal. The human eye perceives these variations in duty cycle as analogous to variations in the level of the input signal.

  18. Ground-water studies and analog models

    USGS Publications Warehouse

    Robinove, Charles Joseph

    1962-01-01

    Hydrologists make ground-water studies to aid managers and users of water resources in solving their problems in the development and management of ground water. Geologic and hydrologic information provides the basic knowledge for construction of electric analog models that portray the ground-water system in miniature. Analog models can be analyzed electrically, and the results of the analysis are presented in terms of the ground-water system so that the effects of alternative methods of water development can be assessed.

  19. (-)-Botryodiplodin, A Unique Ribose Analog Toxin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many toxins owe their mechanisms of action to being structural analogs of essential metabolites, messengers or structural components. Examples range from tubo-curare to penicillin. Ribose plays a unique role in the metabolism of living organisms, whether prokaryotes or eukaryotes. It and its deri...

  20. The GMO-Nanotech (Dis)Analogy?

    ERIC Educational Resources Information Center

    Sandler, Ronald; Kay, W. D.

    2006-01-01

    The genetically-modified-organism (GMO) experience has been prominent in motivating science, industry, and regulatory communities to address the social and ethical dimensions of nanotechnology. However, there are some significant problems with the GMO-nanotech analogy. First, it overstates the likelihood of a GMO-like backlash against…

  1. Invention through Form and Function Analogy

    ERIC Educational Resources Information Center

    Rule, Audrey C.

    2015-01-01

    "Invention through Form and Function Analogy" is an invention book for teachers and other leaders working with youth who are involving students in the invention process. The book consists of an introduction and set of nine learning cycle formatted lessons for teaching the principles of invention through the science and engineering design…

  2. A Mechanical Analogy for Ohm's Law.

    ERIC Educational Resources Information Center

    do Couto Tavares, Milton; And Others

    1991-01-01

    A mechanical analogy between the microscopic motion of a charged carrier in an ordinary resistor and the macroscopic motion of a ball falling along a slanted board covered with a lattice of nails is introduced. The Drude model is also introduced to include the case of inelastic collisions. Computer simulation of the motion is described. (KR)

  3. Radiation Behavior of Analog Neural Network Chip

    NASA Technical Reports Server (NTRS)

    Langenbacher, H.; Zee, F.; Daud, T.; Thakoor, A.

    1996-01-01

    A neural network experiment conducted for the Space Technology Research Vehicle (STRV-1) 1-b launched in June 1994. Identical sets of analog feed-forward neural network chips was used to study and compare the effects of space and ground radiation on the chips. Three failure mechanisms are noted.

  4. An Analog Processor for Image Compression

    NASA Technical Reports Server (NTRS)

    Tawel, R.

    1992-01-01

    This paper describes a novel analog Vector Array Processor (VAP) that was designed for use in real-time and ultra-low power image compression applications. This custom CMOS processor is based architectually on the Vector Quantization (VQ) algorithm in image coding, and the hardware implementation fully exploits the inherent parallelism built-in the VQ algorithm.

  5. RF digital-to-analog converter

    DOEpatents

    Conway, P.H.; Yu, D.U.L.

    1995-02-28

    A digital-to-analog converter is disclosed for producing an RF output signal proportional to a digital input word of N bits from an RF reference input, N being an integer greater or equal to 2. The converter comprises a plurality of power splitters, power combiners and a plurality of mixers or RF switches connected in a predetermined configuration. 18 figs.

  6. Classical analog of electromagnetically induced transparency

    NASA Astrophysics Data System (ADS)

    Garrido Alzar, C. L.; Martinez, M. A. G.; Nussenzveig, P.

    2002-01-01

    We present a classical analog of electromagnetically induced transparency (EIT). In a system of just two coupled harmonic oscillators subject to a harmonic driving force, we reproduce the phenomenology observed in EIT. We also describe a simple experiment with two linearly coupled RLC circuits which can be incorporated into an undergraduate laboratory.

  7. Analog Acoustic Expression in Speech Communication

    ERIC Educational Resources Information Center

    Shintel, Hadas; Nusbaum, Howard C.; Okrent, Arika

    2006-01-01

    We present the first experimental evidence of a phenomenon in speech communication we call "analog acoustic expression." Speech is generally thought of as conveying information in two distinct ways: discrete linguistic-symbolic units such as words and sentences represent linguistic meaning, and continuous prosodic forms convey information about…

  8. Radioiodinated fatty acid analogs for myocardial imaging

    SciTech Connect

    Ruyan, M.K.

    1993-01-01

    Fatty acids are the preferred substrate for the normoxic heart. About sixty percent of the energy required by the myocardium is provided by fatty acid [beta]-oxidation. Many scientists have focused on the alterations in fatty acid metabolism in the ischemic heart for the development of radiolabelled fatty acids for functional imaging of the heart. Three main categories of compounds were synthesized: tetrazoles (1 and 2), glycidic and [alpha]-methylene acids (3-5), and analogs of oleic acid (6,7 and 7A). The tetrazole group has a similar pKa and size to that of a carboxyl group; however, such fatty acid analogs cannot undergo normal fatty acid metabolism. Glycidic and [alpha]-methylene analogs are potential irreversible inhibitors of fatty acid metabolism. Oleic acid analogs were investigated to assess the affect of stereochemical consequences on biodistribution. The key intermediates in the synthesis of the target compounds were [omega]-nitrophenyl alkylcarboxylic acids and alcohols, which were made using a variety of cross-coupling reactions. The Wittig reaction, which was used in the synthesis of tetrazole 1 and glycidic acid 3, gave low yields of the cross-coupled products. The remaining target compounds were synthesized by condensation of appropriate RCu (CN) ZnI and substituted benzyl bromides or by Pd[sup II] catalyzed cross-coupling of substituted arylhalides with suitable alkynes. The latter two reactions produced much higher yields of the desired products. All of the target compounds were radiolabeled with [sup 125]I by various Cu(I) catalyzed radioiodine exchange procedures and were then subjected to tissue biodistribution (TD) studies in rats. Except for the 15-(4-iodophenyl)-2-methylene-pentadecanoic acid (5), all of the fatty acid analogs failed to surpass clinically-used 15-(4-iodophenyl)pentadecanoic acid (IPPA) in their ability to be taken up and retained by the rat myocardium.

  9. CRC handbook of neurohypophyseal hormone analogs. Volume I

    SciTech Connect

    Jost, K.; Lebl, M.; Brtnik, F.

    1987-01-01

    This book is discussed in two parts. Part one discusses Introductory Remarks. Nomenclature. Natural Forms of Neurohypophyseal Hormones. Synthesis, Purification, and Stability of the Neurohypophyseal Hormone Analogs. Isotopically Modified Analogs. Studies of Analogs Using Physiocochemical and Theoretical Methods. Conformational properties of Neurohypophyseal Hormone Analogs in Solution as Determined bu NMR and Laser Raman Spectroscopies. Other Methods used in the Investigation of Neurohypophyseal Hormone Analog Conformations. Conformation Properties of Analogs in Solution as Revealed by Circular Dichroism Spectroscopy. Conformational Energy Calculations. Quantitative Structure Activity Relationships. References. Part 2 discusses The Use of Neurohypophyseal Hormone Analogs in the Study of Neurophysin-Hormone Interactions. Enzymatic Inactivation. Immunochemistry. Studies of Neurohypopophyseal Hormone Activities at the Cellular Level. Fundamental Biological Evaluation. Important Structural Modifications. Noncoded Amino Acids. Modification of ..cap alpha..-Amino Group; 1-Deamino and 1-Hydroxy Analogs. Modifications in the Issulfide Bridge (Carba-Analogs). Modification of Other Functional Groups. Changes in the Backbone. References. Index.

  10. Multilateral Research Opportunities in Ground Analogs

    NASA Technical Reports Server (NTRS)

    Corbin, Barbara J.

    2015-01-01

    The global economy forces many nations to consider their national investments and make difficult decisions regarding their investment in future exploration. International collaboration provides an opportunity to leverage other nations' investments to meet common goals. The Humans In Space Community shares a common goal to enable safe, reliable, and productive human space exploration within and beyond Low Earth Orbit. Meeting this goal requires efficient use of limited resources and International capabilities. The International Space Station (ISS) is our primary platform to conduct microgravity research targeted at reducing human health and performance risks for exploration missions. Access to ISS resources, however, is becoming more and more constrained and will only be available through 2020 or 2024. NASA's Human Research Program (HRP) is actively pursuing methods to effectively utilize the ISS and appropriate ground analogs to understand and mitigate human health and performance risks prior to embarking on human exploration of deep space destinations. HRP developed a plan to use ground analogs of increasing fidelity to address questions related to exploration missions and is inviting International participation in these planned campaigns. Using established working groups and multilateral panels, the HRP is working with multiple Space Agencies to invite International participation in a series of 30- day missions that HRP will conduct in the US owned and operated Human Exploration Research Analog (HERA) during 2016. In addition, the HRP is negotiating access to Antarctic stations (both US and non-US), the German :envihab and Russian NEK facilities. These facilities provide unique capabilities to address critical research questions requiring longer duration simulation or isolation. We are negotiating release of international research opportunities to ensure a multilateral approach to future analog research campaigns, hoping to begin multilateral campaigns in the

  11. Not all analogies are created equal: Associative and categorical analogy processing following brain damage

    PubMed Central

    Schmidt, Gwenda L.; Cardillo, Eileen R.; Kranjec, Alexander; Lehet, Matthew; Widick, Page; Chatterjee, Anjan

    2012-01-01

    Current research on analogy processing assumes that different conceptual relations are treated similarly. However, just as words and concepts are related in distinct ways, different kinds of analogies may employ distinct types of relationships. An important distinction in how words are related is the difference between associative (dog-bone) and categorical (dog-cat) relations. To test the hypothesis that analogical mapping of different types of relations would have different neural instantiations, we tested patients with left and right hemisphere lesions on their ability to understand two types of analogies, ones expressing an associative relationship and others expressing a categorical relationship. Voxel-based lesion-symptom mapping (VLSM) and behavioral analyses revealed that associative analogies relied on a large left-lateralized language network while categorical analogies relied on both left and right hemispheres. The verbal nature of the task could account for the left hemisphere findings. We argue that categorical relations additionally rely on the right hemisphere because they are more difficult, abstract, and fragile; and contain more distant relationships. PMID:22402184

  12. Not all analogies are created equal: Associative and categorical analogy processing following brain damage.

    PubMed

    Schmidt, Gwenda L; Cardillo, Eileen R; Kranjec, Alexander; Lehet, Matthew; Widick, Page; Chatterjee, Anjan

    2012-06-01

    Current research on analogy processing assumes that different conceptual relations are treated similarly. However, just as words and concepts are related in distinct ways, different kinds of analogies may employ distinct types of relationships. An important distinction in how words are related is the difference between associative (dog-bone) and categorical (dog-cat) relations. To test the hypothesis that analogical mapping of different types of relations would have different neural instantiations, we tested patients with left and right hemisphere lesions on their ability to understand two types of analogies, ones expressing an associative relationship and others expressing a categorical relationship. Voxel-based lesion-symptom mapping (VLSM) and behavioral analyses revealed that associative analogies relied on a large left-lateralized language network while categorical analogies relied on both left and right hemispheres. The verbal nature of the task could account for the left hemisphere findings. We argue that categorical relations additionally rely on the right hemisphere because they are more difficult, abstract, and fragile, and contain more distant relationships.

  13. Playing with a double-edged sword: Analogies in biochemistry

    NASA Astrophysics Data System (ADS)

    Orgill, Marykay

    Analogy pervades our everyday reasoning. No situation we encounter is exactly like a situation we have encountered previously, and our ability to learn and survive in the world is based on our ability to find similarities between past and present situations and use the knowledge we have gained from past situations to manage current situations. Analogies can be powerful teaching tools because they can make new material intelligible to students by comparing it to material that is already familiar. It is clear, though, that not all analogies are good and that not all good analogies are useful to all students. In this study, I have used textbook analysis, classroom observations, student interviews and instructor interviews to determine the role that analogies play in biochemistry learning. Analogies are an important teaching technique in biochemistry classes, being used more often in both biochemistry classes and textbooks than they are in high school chemistry classes and textbooks. Most biochemistry students like, pay particular attention to, and remember the analogies their instructors provide; and they use these analogies to understand, visualize, and recall information from class. Even though students like and use analogies, they do not understand what analogies are or the mechanism by which they improve learning. For the students, analogies are simply any teaching technique that eases understanding, visualization, or recall. Instructors, on the other hand, have a good understanding of what analogies are and of how they should be presented in class; but they do not use analogies as effectively as they should. They do not plan, explain or identify the limitations of the analogies they use in class. However, regardless of how effectively instructors present analogies in class, this study indicates that, in general, analogies are useful in promoting understanding, visualization, recall, and motivation in biochemistry students at all levels. They would be even more

  14. A new program on digitizing analog seismograms

    NASA Astrophysics Data System (ADS)

    Wang, Maofa; Jiang, Qigang; Liu, Qingjie; Huang, Meng

    2016-08-01

    Historical seismograms contain a great variety of useful information which can be used in the study of earthquakes. It is necessary for researchers to digitize analog records and extract the information just as modern computing analysis requires. Firstly, an algorithm based on color scene filed method is presented in order to digitize analog seismograms. Secondly, an interactive software program using C# has been developed to digitize seismogram traces from raster files quickly and accurately. The program can deal with gray-scale images stored in a suitable file format and it offers two different methods: manual digitization and automatic digitization. The test result of the program shows that the methods presented in this paper can lead to good performance.

  15. Terrestrial analogs of the hellespontus dunes, Mars

    USGS Publications Warehouse

    Breed, C.S.

    1977-01-01

    Geomorphic features in the Hellespontus region, Mars, were compared with dunes of the crescentic ridge type in numerous terrestrial sand seas quantitatively by dimensional analysis of dune lengths, widths, and wavelengths. Mean values for the Hellespontus dunes are close to mean values derived from measurements of all sampled terrestrial sand seas. Terrestrial analogs of form and areal distribution of the Hellespontus dunes are shown by comparison of scale ratios derived from the measurements. Dunes of similar form occur in South West Africa, in Pakistan, in the southeastern Arabian peninsula, in the Sahara, in eastern USSR and northern China, and in western North America. Terrestrial analogs closest to form and areal distribution of the Hellespontus dunes are in the Kara Kum Desert, Turkmen SSR, and in the Ala Shan (Gobi) Desert, China. ?? 1977.

  16. Optimal neural computations require analog processors

    SciTech Connect

    Beiu, V.

    1998-12-31

    This paper discusses some of the limitations of hardware implementations of neural networks. The authors start by presenting neural structures and their biological inspirations, while mentioning the simplifications leading to artificial neural networks. Further, the focus will be on hardware imposed constraints. They will present recent results for three different alternatives of parallel implementations of neural networks: digital circuits, threshold gate circuits, and analog circuits. The area and the delay will be related to the neurons` fan-in and to the precision of their synaptic weights. The main conclusion is that hardware-efficient solutions require analog computations, and suggests the following two alternatives: (i) cope with the limitations imposed by silicon, by speeding up the computation of the elementary silicon neurons; (2) investigate solutions which would allow the use of the third dimension (e.g. using optical interconnections).

  17. Analog Computation by DNA Strand Displacement Circuits.

    PubMed

    Song, Tianqi; Garg, Sudhanshu; Mokhtar, Reem; Bui, Hieu; Reif, John

    2016-08-19

    DNA circuits have been widely used to develop biological computing devices because of their high programmability and versatility. Here, we propose an architecture for the systematic construction of DNA circuits for analog computation based on DNA strand displacement. The elementary gates in our architecture include addition, subtraction, and multiplication gates. The input and output of these gates are analog, which means that they are directly represented by the concentrations of the input and output DNA strands, respectively, without requiring a threshold for converting to Boolean signals. We provide detailed domain designs and kinetic simulations of the gates to demonstrate their expected performance. On the basis of these gates, we describe how DNA circuits to compute polynomial functions of inputs can be built. Using Taylor Series and Newton Iteration methods, functions beyond the scope of polynomials can also be computed by DNA circuits built upon our architecture. PMID:27363950

  18. Understanding the Nature of PHL 1811 Analogs

    NASA Astrophysics Data System (ADS)

    Brandt, W. N.

    2012-09-01

    A central tenet of X-ray astronomy is that luminous X-ray emission is a universal property of efficiently accreting supermassive black holes. However, we have recently studied a population of type 1 quasars that challenge this idea: PHL 1811 analogs. These objects are all X-ray weak and have exceptional UV emission-line properties. We propose snapshot observations of 10 bright radio-quiet PHL 1811 analogs that will more than double the sample of these objects with sensitive X-ray coverage. The improved sample size will better characterize the X-ray weakness of this population and allow correlation tests with emission-line properties. The improved photon statistics will aid joint spectral analyses investigating hints of hard X-ray spectra and X-ray absorption.

  19. Parabolic flight as a spaceflight analog.

    PubMed

    Shelhamer, Mark

    2016-06-15

    Ground-based analog facilities have had wide use in mimicking some of the features of spaceflight in a more-controlled and less-expensive manner. One such analog is parabolic flight, in which an aircraft flies repeated parabolic trajectories that provide short-duration periods of free fall (0 g) alternating with high-g pullout or recovery phases. Parabolic flight is unique in being able to provide true 0 g in a ground-based facility. Accordingly, it lends itself well to the investigation of specific areas of human spaceflight that can benefit from this capability, which predominantly includes neurovestibular effects, but also others such as human factors, locomotion, and medical procedures. Applications to research in artificial gravity and to effects likely to occur in upcoming commercial suborbital flights are also possible.

  20. Analog data transmission via fiber optics

    SciTech Connect

    Cisneros, E.L.; Burgueno, G.F.

    1986-10-01

    In the SLAC Linear Collider Detector (SLD), as in most high-energy particle detectors, the electromagnetic noise environment is the limiting factor in electronic readout performance. Front-end electronics are particulary susceptible to electromagnetic interference (EMI), and great care has been taken to minimize its effects. The transfer of preprocessed analog signals from the detector environs, to the remote digital processing electronics, by conventional means (via metal conductors), may ultimately limit the performance of the system. Because it is highly impervious to EMI and ground loops, a fiber-optic medium has been chosen for the transmission of these signals. This paper describes several fiber-optic transmission schemes which satisfy the requirements of the SLD analog data transmission.

  1. Submarine Analogs to Venusian Pancake Domes

    NASA Technical Reports Server (NTRS)

    Bridges, Nathan T.

    1995-01-01

    The morphology and dimensions of the large diameter, steep-sided, flat-topped "pancake domes" on Venus make them unlike any type of terrestrial subaerial volcano. Comparisons between images of Hawaiian seamounts and pancake domes show similarities in shapes and secondary features. The morphometry of pancake domes is closer to that of Pacific seamounts than subaerial lava domes. Considering both morphology and morphometry, seamounts seem a better analog to the pancake domes. The control of volatile exsolution by pressure on Venus and the seafloor can cause lavas to have similar viscosities and densities, although the latter will be counteracted by high buoyancy underwater. However, analogous effects of the Venusian and seafloor alone are probably not sufficient to produce similar volcanoes. Rather, Venusian lavas of various compositions may behave like basalt on the seafloor if appropriate rates and modes of extrusion and planetary thermal structure are also considered.

  2. Nonintentional analogical inference in text comprehension.

    PubMed

    Day, Samuel B; Gentner, Dedre

    2007-01-01

    We present findings suggesting that analogical inference processes can play a role in fluent comprehension and interpretation. Participants were found to use information from a prior relationally similar example in understanding the content of a later example, but they reported that they were not aware of having done so. These inference processes were sensitive to structural mappings between the two instances, ruling out explanations based solely on more general kinds of activation, such as priming. Reading speed measures were consistent with the possibility that these inferences had taken place during encoding of the target rather than during the later recognition test. These findings suggest that analogical mapping, though often viewed as an explicit deliberative process, can sometimes operate without intent or even awareness.

  3. Observing spin optodynamical analog of cavity optomechanics

    NASA Astrophysics Data System (ADS)

    Gerber, Justin; Kohler, Jonathan; Spethmann, Nicolas; Schreppler, Sydney; Stamper-Kurn, Dan

    2016-05-01

    Cavity Optomechanics has been realized in many diverse systems and led to many interesting results such as ponderomotive squeezing of light, beyond-SQL measurement sensitivity, and squeezing of mechanical oscillators. Optical cavities also allow sensitive measurements of the spin of an atomic ensemble. It has been proposed to utilize this sensitivity to realize an analog of optomechanics by measuring the precession of small excitations of a spin-oscillator around a transverse magnetic field. I will present our recent work in which we realize optomechanical analogs in our system such as cavity-assisted cooling and amplification and optical spring shifts. In addition, the presence of a high-energy `ground state' of the spin oscillator allows the realization of an effective negative mass oscillator which is demonstrated by an inverted sideband asymmetry. In our ongoing work we attempt to realize coherent quantum noise cancelation by coupling spin oscillation with mechanical oscillation.

  4. Terrestrial analogs of the Hellespontus dunes, Mars

    NASA Technical Reports Server (NTRS)

    Breed, C. S.

    1977-01-01

    Geomorphic features in the Hellespontus region, Mars, were compared with dunes of the crescentic ridge type in numerous terrestrial sand seas quantitatively by dimensional analysis of dune lengths, widths, and wavelengths. Mean values for the Hellespontus dunes are close to mean values derived from measurements of all sampled terrestrial sand seas. Terrestrial analogs of form and areal distribution of the Hellespontus dunes are shown by comparison of scale ratios derived from the measurements. Dunes of similar form occur in South West Africa, in Pakistan, in the southeastern Arabian peninsula, in the Sahara, in eastern USSR and northern China, and in western North America. Terrestrial analogs closest to form and areal distribution of the Hellespontus dunes are in the Kara Kum Desert, Turkmen SSR, and in the Ala Shan (Gobi) Desert, China.

  5. Biomedical sensor design using analog compressed sensing

    NASA Astrophysics Data System (ADS)

    Balouchestani, Mohammadreza; Krishnan, Sridhar

    2015-05-01

    The main drawback of current healthcare systems is the location-specific nature of the system due to the use of fixed/wired biomedical sensors. Since biomedical sensors are usually driven by a battery, power consumption is the most important factor determining the life of a biomedical sensor. They are also restricted by size, cost, and transmission capacity. Therefore, it is important to reduce the load of sampling by merging the sampling and compression steps to reduce the storage usage, transmission times, and power consumption in order to expand the current healthcare systems to Wireless Healthcare Systems (WHSs). In this work, we present an implementation of a low-power biomedical sensor using analog Compressed Sensing (CS) framework for sparse biomedical signals that addresses both the energy and telemetry bandwidth constraints of wearable and wireless Body-Area Networks (BANs). This architecture enables continuous data acquisition and compression of biomedical signals that are suitable for a variety of diagnostic and treatment purposes. At the transmitter side, an analog-CS framework is applied at the sensing step before Analog to Digital Converter (ADC) in order to generate the compressed version of the input analog bio-signal. At the receiver side, a reconstruction algorithm based on Restricted Isometry Property (RIP) condition is applied in order to reconstruct the original bio-signals form the compressed bio-signals with high probability and enough accuracy. We examine the proposed algorithm with healthy and neuropathy surface Electromyography (sEMG) signals. The proposed algorithm achieves a good level for Average Recognition Rate (ARR) at 93% and reconstruction accuracy at 98.9%. In addition, The proposed architecture reduces total computation time from 32 to 11.5 seconds at sampling-rate=29 % of Nyquist rate, Percentage Residual Difference (PRD)=26 %, Root Mean Squared Error (RMSE)=3 %.

  6. Analog Processor To Solve Optimization Problems

    NASA Technical Reports Server (NTRS)

    Duong, Tuan A.; Eberhardt, Silvio P.; Thakoor, Anil P.

    1993-01-01

    Proposed analog processor solves "traveling-salesman" problem, considered paradigm of global-optimization problems involving routing or allocation of resources. Includes electronic neural network and auxiliary circuitry based partly on concepts described in "Neural-Network Processor Would Allocate Resources" (NPO-17781) and "Neural Network Solves 'Traveling-Salesman' Problem" (NPO-17807). Processor based on highly parallel computing solves problem in significantly less time.

  7. Analog optical computing primitives in silicon photonics.

    PubMed

    Jiang, Yunshan; DeVore, Peter T S; Jalali, Bahram

    2016-03-15

    Optical computing accelerators help alleviate bandwidth and power consumption bottlenecks in electronics. We show an approach to implementing logarithmic-type analog co-processors in silicon photonics and use it to perform the exponentiation operation and the recovery of a signal in the presence of multiplicative distortion. The function is realized by exploiting nonlinear-absorption-enhanced Raman amplification saturation in a silicon waveguide. PMID:26977687

  8. Survey of Evaluated Isobaric Analog States

    SciTech Connect

    MacCormick, M.

    2014-06-15

    Isobaric analog states (IAS) can be used to estimate the masses of members belonging to the same isospin multiplet. Experimental and estimated IAS have been used frequently within the Atomic Mass Evaluation (AME) in the past, but the associated set of evaluated masses have been published for the first time in AME2012 and NUBASE2012. In this paper the current trends of the isobaric multiplet mass equation (IMME) coefficients are shown. The T = 2 multiplet is used as a detailed illustration.

  9. Synthesis and biological evaluation of platensimycin analogs

    SciTech Connect

    Shen, Hong C.; Ding, Fa-Xiang; Singh, Sheo B.; Parthasarathy, Gopalakrishnan; Soisson, Stephen M.; Ha, Sookhee N.; Chen, Xun; Kodali, Srinivas; Wang, Jun; Dorso, Karen; Tata, James R.; Hammond, Milton L.; MacCoss, Malcolm; Colletti, Steven L.

    2009-07-23

    Platensimycin (1) displays antibacterial activity due to its inhibition of the elongation condensing enzyme (FabF), a novel mode of action that could potentially lead to a breakthrough in developing a new generation of antibiotics. The medicinal chemistry efforts were focused on the modification of the enone moiety of platensimycin and several analogs showed significant activity against FabF and possess antibacterial activity.

  10. The 2012 Moon and Mars Analog Mission

    NASA Technical Reports Server (NTRS)

    Graham, Lee

    2014-01-01

    The 2012 Moon and Mars Analog Mission Activities (MMAMA) scientific investigations were completed on Mauna Kea volcano in Hawaii in July 2012. The investigations were conducted on the southeast flank of the Mauna Kea volcano at an elevation of approximately 11,500 ft. This area is known as "Apollo Valley" and is in an adjacent valley to the Very Large Baseline Array dish antenna.

  11. Ophiolites as Analogs to Habitats on Mars

    NASA Technical Reports Server (NTRS)

    Schulte, M.; Blake, D. F.

    2003-01-01

    Ophiolite sequences that are located in northern and central California provide easily accessible areas that serve as good analogs for martian crustal rocks. The rock types found in a typical ophiolite sequence compare well with those found in the Mars meteorites, and those expected from spectrophotometric analysis. We have begun investigating and characterizing these sites in order to understand better the processes that may be responsible for the groundwater chemistry, mineralogy and biology of similar environments on Mars.

  12. Magnetic Analog Random-Access Memory

    NASA Technical Reports Server (NTRS)

    Katti, Romney R.; Wu, Jiin-Chuan; Stadler, Henry L.

    1991-01-01

    Proposed integrated, solid-state, analog random-access memory base on principle of magnetic writing and magnetoresistive reading. Current in writing conductor magnetizes storage layer. Remanent magnetization in storage layer penetrates readout layer and detected by magnetoresistive effect or Hall effect. Memory cells are part of integrated circuit including associated reading and writing transistors. Intended to provide high storage density and rapid access, nonvolatile, consumes little power, and relatively invulnerable to ionizing radiation.

  13. Synthetic analog computation in living cells.

    PubMed

    Daniel, Ramiz; Rubens, Jacob R; Sarpeshkar, Rahul; Lu, Timothy K

    2013-05-30

    A central goal of synthetic biology is to achieve multi-signal integration and processing in living cells for diagnostic, therapeutic and biotechnology applications. Digital logic has been used to build small-scale circuits, but other frameworks may be needed for efficient computation in the resource-limited environments of cells. Here we demonstrate that synthetic analog gene circuits can be engineered to execute sophisticated computational functions in living cells using just three transcription factors. Such synthetic analog gene circuits exploit feedback to implement logarithmically linear sensing, addition, ratiometric and power-law computations. The circuits exhibit Weber's law behaviour as in natural biological systems, operate over a wide dynamic range of up to four orders of magnitude and can be designed to have tunable transfer functions. Our circuits can be composed to implement higher-order functions that are well described by both intricate biochemical models and simple mathematical functions. By exploiting analog building-block functions that are already naturally present in cells, this approach efficiently implements arithmetic operations and complex functions in the logarithmic domain. Such circuits may lead to new applications for synthetic biology and biotechnology that require complex computations with limited parts, need wide-dynamic-range biosensing or would benefit from the fine control of gene expression.

  14. Neurotoxicity of artemisinin analogs in vitro.

    PubMed Central

    Wesche, D L; DeCoster, M A; Tortella, F C; Brewer, T G

    1994-01-01

    The sesquiterpene endoperoxide antimalarial agents arteether and artemether have been reported to cause neurotoxicity with a discrete distribution in the brain stems of rats and dogs after multiple doses. The nature and distribution of the brain lesions suggest a specific neuronal target, the identity of which is unknown. In order to further investigate artemisinin analog-induced neurotoxicity, we evaluated several in vitro models: fetal rat primary neuronal cultures, fetal rat secondary astrocyte cultures, and transformed neuronal cultures (rat-derived neuroblastoma NG108-15 and mouse-derived neuroblastoma Neuro-2a). Results indicate that toxicity was specific for neuronal cell types but not glial cells. Neurotoxicity, as indexed by liberation of lactate dehydrogenase and/or inhibition of radiolabelled-leucine uptake, was seen in all three neuronal culture types, implicating a common target. In vitro neurotoxicity was dose and time dependent. Acute exposure to drug results in delayed, but not immediate, manifestations of cell toxicity. Structure-activity comparisons indicate that substitutions at positions 9 and 10 and stereoisomerism at position 10 of the artemisinin backbone influence the degree of toxicity. The endoperoxide is necessary but not sufficient for toxicity. Sodium artesunate and dihydroartemisinin, a metabolite common to all artemisinin analogs currently being developed for clinical use, are the most potent of all analogs tested. These results are consistent with a specific neuronal target, but the identity of the target(s) remains unknown. PMID:7986012

  15. Clinical utility of insulin and insulin analogs

    PubMed Central

    Sanlioglu, Ahter D.; Altunbas, Hasan Ali; Balci, Mustafa Kemal; Griffith, Thomas S.; Sanlioglu, Salih

    2013-01-01

    Diabetes is a pandemic disease characterized by autoimmune, genetic and metabolic abnormalities. While insulin deficiency manifested as hyperglycemia is a common sequel of both Type-1 and Type-2 diabetes (T1DM and T2DM), it does not result from a single genetic defect—rather insulin deficiency results from the functional loss of pancreatic β cells due to multifactorial mechanisms. Since pancreatic β cells of patients with T1DM are destroyed by autoimmune reaction, these patients require daily insulin injections. Insulin resistance followed by β cell dysfunction and β cell loss is the characteristics of T2DM. Therefore, most patients with T2DM will require insulin treatment due to eventual loss of insulin secretion. Despite the evidence of early insulin treatment lowering macrovascular (coronary artery disease, peripheral arterial disease and stroke) and microvascular (diabetic nephropathy, neuropathy and retinopathy) complications of T2DM, controversy exists among physicians on how to initiate and intensify insulin therapy. The slow acting nature of regular human insulin makes its use ineffective in counteracting postprandial hyperglycemia. Instead, recombinant insulin analogs have been generated with a variable degree of specificity and action. Due to the metabolic variability among individuals, optimum blood glucose management is a formidable task to accomplish despite the presence of novel insulin analogs. In this article, we present a recent update on insulin analog structure and function with an overview of the evidence on the various insulin regimens clinically used to treat diabetes. PMID:23584214

  16. Backtracking quantum trajectories with analog feedback

    NASA Astrophysics Data System (ADS)

    de Lange*, G.; Ristè*, D.; Tiggelman, M. J.; Eichler, C.; Tornberg, L.; Johansson, G.; Wallraff, A.; Schouten, R. N.; Dicarlo, L.

    2014-03-01

    Circuit quantum electrodynamics offers a nearly ideal platform for the fundamental study of continuous quantum measurement. A nondemolition measurement of a superconducting qubit can be performed via homodyne detection of microwave transmission through a dispersively coupled cavity. By boosting the homodyne signal with a nearly noiseless phase-sensitive parametric amplifier, we experimentally show that a form of measurement backaction, consisting of stochastic quantum phase kicks on the measured qubit, is highly correlated with the fluctuations in the continuous homodyne record. We demonstrate a real-time analog feedback scheme that counteracts these phase kicks and thereby reduces measurement-induced dephasing. We develop a numerical optimization technique to overcome the bandwidth limitations of the amplification chain and provide a theoretical model for the optimization result. A quantum efficiency of 50% is extracted for the complete analog feedback loop. Finally, we discuss the integration of this analog feedback technique to improve performance in our recent demonstration of entanglement by dispersive parity measurement. *equal contribution. Research funded by NWO and the EU projects SOLID and SCALEQIT.

  17. Sensing Methods for Detecting Analog Television Signals

    NASA Astrophysics Data System (ADS)

    Rahman, Mohammad Azizur; Song, Chunyi; Harada, Hiroshi

    This paper introduces a unified method of spectrum sensing for all existing analog television (TV) signals including NTSC, PAL and SECAM. We propose a correlation based method (CBM) with a single reference signal for sensing any analog TV signals. In addition we also propose an improved energy detection method. The CBM approach has been implemented in a hardware prototype specially designed for participating in Singapore TV white space (WS) test trial conducted by Infocomm Development Authority (IDA) of the Singapore government. Analytical and simulation results of the CBM method will be presented in the paper, as well as hardware testing results for sensing various analog TV signals. Both AWGN and fading channels will be considered. It is shown that the theoretical results closely match with those from simulations. Sensing performance of the hardware prototype will also be presented in fading environment by using a fading simulator. We present performance of the proposed techniques in terms of probability of false alarm, probability of detection, sensing time etc. We also present a comparative study of the various techniques.

  18. Automated D/3 to Visio Analog Diagrams

    2000-08-10

    ADVAD1 reads an ASCII file containing the D/3 DCS MDL input for analog points for a D/3 continuous database. It uses the information in the files to create a series of Visio files representing the structure of each analog chain, one drawing per Visio file. The actual drawing function is performed by Visio (requires Visio version 4.5+). The user can configure the program to select which fields in the database are shown on the diagrammore » and how the information is to be presented. This gives a visual representation of the structure of the analog chains, showing selected fields in a consistent manner. Updating documentation can be done easily and the automated approach eliminates human error in the cadding process. The program can also create the drawings far faster than a human operator is capable, able to create approximately 270 typical diagrams in about 8 minutes on a Pentium II 400 MHz PC. The program allows for multiple option sets to be saved to provide different settings (i.e., different fields, different field presentations, and /or different diagram layouts) for various scenarios or facilities on one workstation. Option sets may be exported from the Windows registry to allow duplication of settings on another workstation.« less

  19. Targeting thyroid diseases with TSH receptor analogs.

    PubMed

    Galofré, Juan C; Chacón, Ana M; Latif, Rauf

    2013-12-01

    The thyroid-stimulating hormone (TSH) receptor (TSHR) is a major regulator of thyroid function and growth, and is the key antigen in several pathological conditions including hyperthyroidism, hypothyroidism, and thyroid tumors. Various effective treatment strategies are currently available for many of these clinical conditions such as antithyroid drugs or radioiodine therapy, but they are not devoid of side effects. In addition, treatment of complications of Graves' disease such as Graves' ophthalmopathy is often difficult and unsatisfactory using current methods. Recent advances in basic research on both in vitro and in vivo models have suggested that TSH analogs could be used for diagnosis and treatment of some of the thyroid diseases. The advent of high-throughput screening methods has resulted in a group of TSH analogs called small molecules, which have the potential to be developed as promising drugs. Small molecules are low molecular weight compounds with agonist, antagonist and, in some cases, inverse agonist activity on TSHR. This short review will focus on current advances in development of TSH analogs and their potential clinical applications. Rapid advances in this field may lead to the conduct of clinical trials of small molecules related to TSHR for the management of Graves' disease, thyroid cancer, and thyroid-related osteoporosis in the coming years.

  20. Periglacial and glacial analogs for Martian landforms

    NASA Technical Reports Server (NTRS)

    Rossbacher, Lisa A.

    1992-01-01

    The list of useful terrestrial analogs for Martian landforms has been expanded to include: features developed by desiccation processes; catastrophic flood features associated with boulder-sized materials; and sorted ground developed at a density boundary. Quantitative analytical techniques developed for physical geography have been adapted and applied to planetary studies, including: quantification of the patterns of polygonally fractured ground to describe pattern randomness independent of pattern size, with possible correlation to the mechanism of origin and quantification of the relative area of a geomorphic feature or region in comparison to planetary scale. Information about Martian geomorphology studied in this project was presented at professional meetings world-wide, at seven colleges and universities, in two interactive televised courses, and as part of two books. Overall, this project has expanded the understanding of the range of terrestrial analogs for Martian landforms, including identifying several new analogs. The processes that created these terrestrial features are characterized by both cold temperatures and low humidity, and therefore both freeze-thaw and desiccation processes are important. All these results support the conclusion that water has played a significant role in the geomorphic history of Mars.

  1. Scientific Analogies and Their Use in Teaching Science

    NASA Astrophysics Data System (ADS)

    Kipnis, Nahum

    Analogy in science knew its successes and failures, as illustrated by examples from the eighteenth-century physics. At times, some scientists abstained from using a certain analogy on the ground that it had not yet been demonstrated. Several false discoveries in the 18th and early 19th centuries appeared to support their caution. It is now clear that such a position reflected a methodological confusion that resulted from a failure to distinguish between particular and general analogies. Considering analogy as a hierarchical structure provides a new insight into "testing an analogy". While warning science teachers of dangers associated with use of analogy, historical cases and their analysis provided here may encourage them to use analogy more extensively while avoiding misconceptions. An argument is made that the history of science may be a better guide than philosophy of science and cognitive psychology when it concerns the role of analogy in science and in teaching science for understanding.

  2. [Relationship between chemical structure and sweetness. XIV. Analogs of aspartame].

    PubMed

    De Nardo, M

    1977-07-01

    Several analogs structurally related to aspartame were prepared in order to establish if chemical modifications of the molecule might improve sweetness. None of these analogs exhibited any sweet taste; on the contrary in most cases they were bitter.

  3. Interactive Optical Disc Systems: Part 1: Analog Storage.

    ERIC Educational Resources Information Center

    Hessler, David W.

    1984-01-01

    Details distinction between digital and analog data, advantages of analog storage, and optical disc use to store analog data. Configuration and potential of three levels of laser disc systems are explained. Selection of display devices for use with laser disc systems and accessing audio data are addressed. (Continued in next issue.) (EJS)

  4. Using Analogies as an Experiential Learning Technique in Multicultural Education

    ERIC Educational Resources Information Center

    Suthakaran, V.; Filsinger, Keri; White, Brittany

    2013-01-01

    In this article the authors specifically address the use of narratives in the form of analogies as an experiential learning activity. The use of analogies as an experiential learning tool in multicultural education can be helpful in a number of ways. Analogies provide an alternative tool for processing multicultural topics with students who have…

  5. Modern Communication: Exploring Physiological Transmission through Tech-Savvy Analogies

    ERIC Educational Resources Information Center

    Hollabaugh, Christopher R.; Milanick, Mark A.

    2014-01-01

    Analogies are often helpful for students to grasp key physiological concepts; sometimes the technical jargon makes the concept seem more complex than it actually is. In this article the authors provide several analogies for information transfer processes that sometimes confuse students. For an analogy to be useful, of course, it needs to be…

  6. Analogies in Medicine: Valuable for Learning, Reasoning, Remembering and Naming

    ERIC Educational Resources Information Center

    Pena, Gil Patrus; Andrade-Filho, Jose de Souza

    2010-01-01

    Analogies are important tools in human reasoning and learning, for resolving problems and providing arguments, and are extensively used in medicine. Analogy and similarity involve a structural alignment or mapping between domains. This cognitive mechanism can be used to make inferences and learn new abstractions. Through analogies, we try to…

  7. Investigating and Theorizing Discourse during Analogy Writing in Chemistry

    ERIC Educational Resources Information Center

    Bellocchi, Alberto; Ritchie, Stephen M.

    2011-01-01

    Explanations of the role of analogies in learning science at a cognitive level are made in terms of creating bridges between new information and students' prior knowledge. In this empirical study of learning with analogies in an 11th grade chemistry class, we explore an alternative explanation at the "social" level where analogy shapes classroom…

  8. Anti-inflammatory effect of thalidomide dithiocarbamate and dithioate analogs.

    PubMed

    Talaat, Roba; El-Sayed, Waheba; Agwa, Hussein S; Gamal-Eldeen, Amira M; Moawia, Shaden; Zahran, Magdy A H

    2015-08-01

    Thalidomide has anti-inflammatory, immunomodulatory, and anti-angiogenic properties. It has been used to treat a variety of cancers and autoimmune diseases. This study aimed to characterize anti-inflammatory activities of novel thalidomide analogs by exploring their effects on splenocytes proliferation and macrophage functions and their antioxidant activity. MTT assay was used to assess the cytotoxic effect of thalidomide analogs against splenocytes. Tumor necrosis factor (TNF-α) and nuclear factor kappa B (NF-κB-P65) were determined by enzyme-linked immunosorbent assay (ELISA). Nitric oxide (NO) was estimated by colorimetric assay. Antioxidant activity was examined by ORAC assay. Our results demonstrated that thalidomide dithioate analog 2 and thalidomide dithiocarbamate analog 4 produced a slight increase in splenocyte proliferation compared with thalidomide. Thalidomide dithiocarbamate analog 1 is a potent inhibitor of TNF-α production, whereas thalidomide dithiocarbamate analog 5 is a potent inhibitor of both TNF-α and NO. Analog 2 has a pronounced inhibitory effect on NF-κB-P65 production level. All thalidomide analogs showed prooxidant activity against hydroxyl (OH) radical. Analog 1 and thalidomide dithioate analog 3 have prooxidant activity against peroxyl (ROO) radical in relation to thalidomide. On the other hand, analog 4 has a potent scavenging capacity against peroxyl (ROO) radical compared with thalidomide. Taken together, the results of this study suggest that thalidomide analogs might have valuable anti-inflammatory activities with more pronounced effect than thalidomide itself.

  9. Can Pupils Use Taught Analogies for Electric Current?

    ERIC Educational Resources Information Center

    Black, David; Solomon, Joan

    1987-01-01

    Discusses the use of analogies and models for teaching about electric current. Reports on a study in which one group of students used analogies to learn about electric current and one did not. Results indicate that, in this case, analogies did not play a significant role in student understanding. (TW)

  10. Functional DNA: Teaching Infinite Series through Genetic Analogy

    ERIC Educational Resources Information Center

    Kowalski, R. Travis

    2011-01-01

    This article presents an extended analogy that connects infinite sequences and series to the science of genetics, by identifying power series as "DNA for a function." This analogy allows standard topics such as convergence tests or Taylor approximations to be recast in a "forensic" light as mathematical analogs of genetic concepts such as DNA…

  11. Analogical Instruction in Statistics: Implications for Social Work Educators

    ERIC Educational Resources Information Center

    Thomas, Leela

    2008-01-01

    This paper examines the use of analogies in statistics instruction. Much has been written about the difficulty social work students have with statistics. To address this concern, Glisson and Fischer (1987) called for the use of analogies. Understanding of analogical problem solving has surged in the last few decades with the integration of…

  12. Using Analogical Reasoning to Deal with "Deep" Misconceptions in Physics.

    ERIC Educational Resources Information Center

    Clement, John; Brown, David

    In this paper examples of the role of analogical reasoning in expert problem solving are presented. These are intended to show that using an analogy can change an expert's understanding of a problem situation by changing the conceptual model he or she uses to think about the situation. This suggests that using a good analogy may allow students to…

  13. When Reasoning Modifies Memory: Schematic Assimilation Triggered by Analogical Mapping

    ERIC Educational Resources Information Center

    Vendetti, Michael S.; Wu, Aaron; Rowshanshad, Ebi; Knowlton, Barbara J.; Holyoak, Keith J.

    2014-01-01

    Analogical mapping highlights shared relations that link 2 situations, potentially at the expense of information that does not fit the dominant pattern of correspondences. To investigate whether analogical mapping can alter subsequent recognition memory for features of a source analog, we performed 2 experiments with 4-term proportional analogies…

  14. Inviting Argument by Analogy: Analogical-Mapping-Based Comparison Activities as a Scaffold for Small-Group Argumentation

    ERIC Educational Resources Information Center

    Emig, Brandon R.; McDonald, Scott; Zembal-Saul, Carla; Strauss, Susan G.

    2014-01-01

    This study invited small groups to make several arguments by analogy about simple machines. Groups were first provided training on analogical (structure) mapping and were then invited to use analogical mapping as a scaffold to make arguments. In making these arguments, groups were asked to consider three simple machines: two machines that they had…

  15. SSERVI Analog Regolith Simulant Testbed Facility

    NASA Astrophysics Data System (ADS)

    Minafra, Joseph; Schmidt, Gregory; Bailey, Brad; Gibbs, Kristina

    2016-10-01

    The Solar System Exploration Research Virtual Institute (SSERVI) at NASA's Ames Research Center in California's Silicon Valley was founded in 2013 to act as a virtual institute that provides interdisciplinary research centered on the goals of its supporting directorates: NASA Science Mission Directorate (SMD) and the Human Exploration & Operations Mission Directorate (HEOMD).Primary research goals of the Institute revolve around the integration of science and exploration to gain knowledge required for the future of human space exploration beyond low Earth orbit. SSERVI intends to leverage existing JSC1A regolith simulant resources into the creation of a regolith simulant testbed facility. The purpose of this testbed concept is to provide the planetary exploration community with a readily available capability to test hardware and conduct research in a large simulant environment.SSERVI's goals include supporting planetary researchers within NASA, other government agencies; private sector and hardware developers; competitors in focused prize design competitions; and academic sector researchers.SSERVI provides opportunities for research scientists and engineers to study the effects of regolith analog testbed research in the planetary exploration field. This capability is essential to help to understand the basic effects of continued long-term exposure to a simulated analog test environment.The current facility houses approximately eight tons of JSC-1A lunar regolith simulant in a test bin consisting of a 4 meter by 4 meter area, including dust mitigation and safety oversight.Facility hardware and environment testing scenarios could include, Lunar surface mobility, Dust exposure and mitigation, Regolith handling and excavation, Solar-like illumination, Lunar surface compaction profile, Lofted dust, Mechanical properties of lunar regolith, Surface features (i.e. grades and rocks)Numerous benefits vary from easy access to a controlled analog regolith simulant testbed, and

  16. Starch columns: Analog model for basalt columns

    NASA Astrophysics Data System (ADS)

    Müller, Gerhard

    1998-07-01

    Desiccation of starch-water mixtures produces tensile-crack patterns which appear to be interesting, but largely unknown study objects for fracture mechanics, structural geology, and volcanology. This paper concentrates on columnar jointing and on columns in starch. Starch columns have polygonal cross sections and are very similar to basalt columns. They are produced by lamp drying starch specimens with dimensions of several centimeters and have diameters in the millimeter range. The columns develop behind a crack front which propagates from the surface into the interior. The experiments, supported by X ray tomograms, show that polygonal regularity of the crack pattern is not present at the surface but develops during penetration. This transition is steered by a minimum-fracture-energy principle. The analogy between basalt cooling and starch desiccation is far reaching: water concentration in starch is analogous to temperature in basalt, both quantities obey diffusion equations, water loss is equivalent to heat loss, the resulting contraction stresses have similar dependences on depth and time, and in both cases the material strength is exceeded. The starch experiments show that column diameters are controlled by the depth gradient of water concentration at the crack front. High (low) gradients are connected with thin (thick) columns. By analogy, a similar relation with the temperature gradient exists for basalt columns. The (normalized) starch gradients are about 3 orders of magnitude larger than the (normalized) gradients in basalt. This explains why starch columns are much thinner than basalt columns. The gradients are so different, because the crack front speeds differ by a factor of about 10: after 3 days the speed is about 10 mm/d in starch but about 100 mm/d in basalt [Peck, 1978]. The speed difference, in turn, results from the difference of the diffusion constants: the hydraulic diffusivity of starch is 2 orders of magnitude lower than the thermal

  17. Mars-Analog Evaporite Experiment: Initial Results

    NASA Technical Reports Server (NTRS)

    Moore, J. M.; Bullock, M. A.; Sharp, T.G.; Quinn, R.

    2005-01-01

    This research is part of a multiyear experimental investigation to understand the nature and evolution brines and evaporates on Mars. The spectacular discoveries of the MER rovers, particularly those of Opportunity at Meridiani, both illustrate the relevance, as well as guide the future direction, of this work. Here we report the initial results from our just-completed and tested evaporites apparatus, using a synthetic brine analog to our brine experiment simulating a modern Mars environment in which the brine was subjected to rapid evaporation under modern Martian conditions. Additional information is included in the original extended abstract.

  18. Analog synthesized fast-variable linear load

    NASA Technical Reports Server (NTRS)

    Niedra, Janis M.

    1991-01-01

    A several kilowatt power level, fast-variable linear resistor was synthesized by using analog components to control the conductance of power MOSFETs. Risetimes observed have been as short as 500 ns with respect to the control signal and 1 to 2 microseconds with respect to the power source voltage. A variant configuration of this load that dissipates a constant power set by a control signal is indicated. Replacement of the MOSFETs by static induction transistors (SITs) to increase power handling, speed and radiation hardness is discussed.

  19. Analog synthesized fast-variable linear load

    NASA Technical Reports Server (NTRS)

    Niedra, Janis M.

    1991-01-01

    A several-kilowatt power level, fast-variable linear resistor has been synthesized by using analog components to control the conductance of power MOSFETs. Risetimes observed have been as short as 500 ns with respect to the control signal and 1 to 2 microsec with respect to the power source voltage. A variant configuration of this load that dissipates a constant power set by a control signal is indicated. Replacement of the MOSFETs by static induction transistors to increase power handling, speed, and radiation hardness is discussed.

  20. Soviet Space Stations as Analogs, Second Edition

    NASA Technical Reports Server (NTRS)

    Bluth, B. J.; Helppie, Martha

    1986-01-01

    The available literature that discusses the various aspects of the Soviet Salyut 6 and Salyut 7 space staions are examined as related to human productivity. The methodology for this analog was a search of unclassified literature. Additional information was obtained in interviews with the cosmonauts and some Soviet space personnel. Topics include: general layout and design of the spacecraft system; cosmonauts role in maintenance and repair; general layout and design of the Mir complex; effects of the environment on personnel; information and computer systems; organization systems; personality systems; and physical conditin of the cosmonaut.

  1. ANALOG QUANTUM NEURON FOR FUNCTIONS APPROXIMATION

    SciTech Connect

    A. EZHOV; A. KHROMOV; G. BERMAN

    2001-05-01

    We describe a system able to perform universal stochastic approximations of continuous multivariable functions in both neuron-like and quantum manner. The implementation of this model in the form of multi-barrier multiple-silt system has been earlier proposed. For the simplified waveguide variant of this model it is proved, that the system can approximate any continuous function of many variables. This theorem is also applied to the 2-input quantum neural model analogical to the schemes developed for quantum control.

  2. Pyrrolidine nucleotide analogs with a tunable conformation

    PubMed Central

    Poštová Slavětínská, Lenka; Rejman, Dominik

    2014-01-01

    Summary Conformational preferences of the pyrrolidine ring in nucleotide analogs 7–14 were investigated by means of NMR and molecular modeling. The effect of the relative configuration of hydroxy and nucleobase substituents as well as the effect of the alkylation or acylation of the pyrrolidine nitrogen atom on the conformation of the pyrrolidine ring were studied. The results of a conformational analysis show that the alkylation/acylation can be effectively used for tuning the pyrrolidine conformation over the whole pseudorotation cycle. PMID:25246956

  3. Scalable analog wavefront sensor with subpixel resolution

    NASA Astrophysics Data System (ADS)

    Wilcox, Michael

    2006-06-01

    Standard Shack-Hartman wavefront sensors use a CCD element to sample position and distortion of a target or guide star. Digital sampling of the element and transfer to a memory space for subsequent computation adds significant temporal delay, thus, limiting the spatial frequency and scalability of the system as a wavefront sensor. A new approach to sampling uses information processing principles in an insect compound eye. Analog circuitry eliminates digital sampling and extends the useful range of the system to control a deformable mirror and make a faster, more capable wavefront sensor.

  4. Solid-state-based analog of optomechanics

    DOE PAGES

    Naumann, Nicolas L.; Droenner, Leon; Carmele, Alexander; Chow, Weng W.; Kabuss, Julia

    2016-06-21

    In this study, we investigate a semiconductor quantum dot as a microscopic analog of a basic optomechanical setup. We show that optomechanical features can be reproduced by the solid-state platform, arising from parallels of the underlying interaction processes, which in the optomechanical case is the radiation pressure coupling and in the semiconductor case the electron–phonon coupling. We discuss bistabilities, lasing, and phonon damping, and recover the same qualitative behaviors for the semiconductor and the optomechanical cases expected for low driving strengths. However, in contrast to the optomechanical case, distinct signatures of higher order processes arise in the semiconductor model.

  5. Analog/Digital System for Germanium Thermometer

    NASA Technical Reports Server (NTRS)

    Woodhouse, Christopher

    1988-01-01

    Electronic system containing analog and digital circuits makes high-precision, four-wire measurements of resistance of each germanium resistance thermometer (GRT) in array of devices, using alternating current (ac) of 1 micro-A. At end measurement interval, contents of negative register subtracted from positive one, resulting in very-narrow-band synchronous demodulation of carrier wave and suppression of out-of-band noise. Microprocessor free to perform other duties after measurement complete. Useful in noisy terrestrial environments encountered in factories.

  6. Analogies as categorization phenomena: Studies from scientific discourse

    NASA Astrophysics Data System (ADS)

    Atkins, Leslie Jill

    Studies on the role of analogies in science classrooms have tended to focus on analogies that come from the teacher or curriculum, and not the analogies that students generate. Such studies are derivative of an educational system that values content knowledge over scientific creativity, and derivative of a model of teaching in which the teacher's role is to convey content knowledge. This dissertation begins with the contention that science classrooms should encourage scientific thinking and one role of the teacher is to model that behavior and identify and encourage it in her students. One element of scientific thinking is analogy. This dissertation focuses on student-generated analogies in science, and offers a model for understanding these. I provide evidence that generated analogies are assertions of categorization, and the base of an analogy is the constructed prototype of an ad hoc category. Drawing from research on categorization, I argue that generated analogies are based in schemas and cognitive models. This model allows for a clear distinction between analogy and literal similarity; prior to this research analogy has been considered to exist on a spectrum of similarity, differing from literal similarity to the degree that structural relations hold but features do not. I argue for a definition in which generated analogies are an assertion of an unexpected categorization: that is, they are asserted as contradictions to an expected schema.

  7. Digital and Analog Gene Circuits for Biotechnology

    PubMed Central

    Roquet, Nathaniel; Lu, Timothy K.

    2014-01-01

    Biotechnology offers the promise of valuable chemical production via microbial processing of renewable and inexpensive substrates. Thus far, static metabolic engineering strategies have enabled this field to advance industrial applications. However, the industrial scaling of statically engineered microbes inevitably creates inefficiencies due to variable conditions present in large-scale microbial cultures. Synthetic gene circuits that dynamically sense and regulate different molecules can resolve this issue by enabling cells to continuously adapt to variable conditions. These circuits also have the potential to enable next-generation production programs capable of autonomous transitioning between steps in a bioprocess. Here, we review the design and application of two main classes of dynamic gene circuits, digital and analog, for biotechnology. Within the context of these classes, we also discuss the potential benefits of digital-analog interconversion, memory, and multi-signal integration. Though synthetic gene circuits have largely been applied for cellular computation to date, we envision that utilizing them in biotechnology will enhance the efficiency and scope of biochemical production with living cells. PMID:24677719

  8. Inhibition of glucuronokinase by substrate analogs.

    PubMed

    Gillard, D F; Dickinson, D B

    1978-11-01

    Glucuronokinase from Lilium longiflorum pollen was purified 30- to 40- fold on a blue dextran-Sepharose column. Substrate analogs were tested for inhibitory effects, and nucleotide substrate specificity of the enzyme was determined. Nine nucleotides were tested, and all were inhibitory when the substrate was ATP. ADP was competitive with ATP and had a K(i) value of 0.23 mm. None of the other nucleotide triphosphates could effectively substitute for ATP as a nucleotide substrate. Ten mm dATP and ITP reacted only 3% as rapidly as 10 mm ATP, while the rates for 10 mm GTP, CTP, UTP, and TTP were less than 1%. The glucuronic acid analogs, methyl alpha-glucuronoside, methyl beta-glucuronoside, beta-glucuronic acid-1-phosphate, and 4-O-methylglucuronic acid were tested as possible enzyme inhibitors. The three methyl derivatives showed little or no inhibition. The beta-glucuronic acid-1-phosphate was inhibitory, with 50% inhibition obtained at 1 to 3 mm depending on the concentration of the glucuronic acid. It is concluded that the glucuronic acid-binding site on the enzyme is highly selective.

  9. AFEII Analog Front End Board Design Specifications

    SciTech Connect

    Rubinov, Paul; /Fermilab

    2005-04-01

    This document describes the design of the 2nd iteration of the Analog Front End Board (AFEII), which has the function of receiving charge signals from the Central Fiber Tracker (CFT) and providing digital hit pattern and charge amplitude information from those charge signals. This second iteration is intended to address limitations of the current AFE (referred to as AFEI in this document). These limitations become increasingly deleterious to the performance of the Central Fiber Tracker as instantaneous luminosity increases. The limitations are inherent in the design of the key front end chips on the AFEI board (the SVXIIe and the SIFT) and the architecture of the board itself. The key limitations of the AFEI are: (1) SVX saturation; (2) Discriminator to analog readout cross talk; (3) Tick to tick pedestal variation; and (4) Channel to channel pedestal variation. The new version of the AFE board, AFEII, addresses these limitations by use of a new chip, the TriP-t and by architectural changes, while retaining the well understood and desirable features of the AFEI board.

  10. Menaquinone analogs inhibit growth of bacterial pathogens.

    PubMed

    Schlievert, Patrick M; Merriman, Joseph A; Salgado-Pabón, Wilmara; Mueller, Elizabeth A; Spaulding, Adam R; Vu, Bao G; Chuang-Smith, Olivia N; Kohler, Petra L; Kirby, John R

    2013-11-01

    Gram-positive bacteria cause serious human illnesses through combinations of cell surface and secreted virulence factors. We initiated studies with four of these organisms to develop novel topical antibacterial agents that interfere with growth and exotoxin production, focusing on menaquinone analogs. Menadione, 1,4-naphthoquinone, and coenzymes Q1 to Q3 but not menaquinone, phylloquinone, or coenzyme Q10 inhibited the growth and to a greater extent exotoxin production of Staphylococcus aureus, Bacillus anthracis, Streptococcus pyogenes, and Streptococcus agalactiae at concentrations of 10 to 200 μg/ml. Coenzyme Q1 reduced the ability of S. aureus to cause toxic shock syndrome in a rabbit model, inhibited the growth of four Gram-negative bacteria, and synergized with another antimicrobial agent, glycerol monolaurate, to inhibit S. aureus growth. The staphylococcal two-component system SrrA/B was shown to be an antibacterial target of coenzyme Q1. We hypothesize that menaquinone analogs both induce toxic reactive oxygen species and affect bacterial plasma membranes and biosynthetic machinery to interfere with two-component systems, respiration, and macromolecular synthesis. These compounds represent a novel class of potential topical therapeutic agents.

  11. Antarctic analog for dilational bands on Europa

    NASA Astrophysics Data System (ADS)

    Hurford, T. A.; Brunt, K. M.

    2014-09-01

    Europa's surface shows signs of extension, which is revealed as lithospheric dilation expressed along ridges, dilational bands and ridged bands. Ridges, the most common tectonic feature on Europa, comprise a central crack flanked by two raised banks a few hundred meters high on each side. Together these three classes may represent a continuum of formation. In Tufts' Dilational Model ridge formation is dominated by daily tidal cycling of a crack, which can be superimposed with regional secular dilation. The two sources of dilation can combine to form the various band morphologies observed. New GPS data along a rift on the Ross Ice Shelf, Antarctica is a suitable Earth analog to test the framework of Tufts' Dilational Model. As predicted by Tufts' Dilational Model, tensile failures in the Ross Ice Shelf exhibit secular dilation, upon which a tidal signal can be seen. From this analog we conclude that Tufts' Dilational Model for Europan ridges and bands may be credible and that the secular dilation is most likely from a regional source and not tidally driven.

  12. Triton's eruptions analogous to Comet Halley's?

    NASA Astrophysics Data System (ADS)

    Wallis, Max K.; Wickramasinghe, N. C.

    1992-11-01

    It is hypothesized that Triton's geysers are analogous to the remnant activity of Comet Halley, whose outbursts producing a particulate coma are persisting out beyond 12 AU Halley's outbursts are understood as resulting from inward freezing of a subsurface lake or sea that's maintained at greater than 10 m depth via metabolic energy release. Cracking of the ice due to thermal expansion forces generates sporadic emissions of H2O and other gases. Analogous activity on Triton is a manifestation of internal freezing of an interior sea under a km or so of ice. This sea at the present epoch is quite separate from the interior liquid ocean, expected to be maintained at greater than 100 km deep by radiogenic heating. The near-surface sea is maintained also by chemical or metabolic energy and sporadically emits gases and condensates through cracks induced during its freezing. Emissions through the ice cover on both comets and Triton would drive surface geology, thus enabling access to new nutrients and trace elements that may be vital for subterranean biology. Triton's biology would be a relic from its tidal heating phase, when the interior was liquid below a 1-2 km frozen lithosphere.

  13. C-Glycosyl Analogs of Oligosaccharides

    NASA Astrophysics Data System (ADS)

    Vauzeilles, Boris; Urban, Dominique; Doisneau, Gilles; Beau, Jean-Marie

    This chapter covers the synthesis of a large collection of "C-oligosaccharides ", synthetic analogs of naturally occurring oligosaccharides in which a carbon atom replaces the anomeric, interglycosidic oxygen atom. These non-natural constructs are stable to chemical and enzymatic degradation, and are primarily devised to probe carbohydrate-based biological processes. These mainly target carbohydrate-protein interactions such as the modulation of glycoenzyme (glycosylhydrolases and transferases) activities or the design of ligands for lectin Carbohydrate Recognition Domains. The discussion is based on the key carbon-carbon bond assembling steps on carbohydrate templates: ionic (anionic and cationic chemistries, sigmatropic rearrangements) or radical assemblage, and olefin metathesis. Synthetic schemes in which at least one of the monosaccharide units is constructed by total synthesis or by cyclization of acyclic chiral chains are presented separately in a "partial de novo synthesis" section. The review also provides comments, when they are known, on the conformational and binding properties of these synthetic analogs, as well as their biological behavior when tested.

  14. EF-G Activation by Phosphate Analogs.

    PubMed

    Salsi, Enea; Farah, Elie; Ermolenko, Dmitri N

    2016-05-22

    Elongation factor G (EF-G) is a universally conserved translational GTPase that promotes the translocation of tRNA and mRNA through the ribosome. EF-G binds to the ribosome in a GTP-bound form and subsequently catalyzes GTP hydrolysis. The contribution of the ribosome-stimulated GTP hydrolysis by EF-G to tRNA/mRNA translocation remains debated. Here, we show that while EF-G•GDP does not stably bind to the ribosome and induce translocation, EF-G•GDP in complex with phosphate group analogs BeF3(-) and AlF4(-) promotes the translocation of tRNA and mRNA. Furthermore, the rates of mRNA translocation induced by EF-G in the presence of GTP and a non-hydrolyzable analog of GTP, GDP•BeF3(-) are similar. Our results are consistent with the model suggesting that GTP hydrolysis is not directly coupled to mRNA/tRNA translocation. Hence, GTP binding is required to induce the activated, translocation-competent conformation of EF-G while GTP hydrolysis triggers EF-G release from the ribosome. PMID:27063503

  15. Palytoxin and Analogs: Biological and Ecological Effects

    PubMed Central

    Ramos, Vítor; Vasconcelos, Vítor

    2010-01-01

    Palytoxin (PTX) is a potent marine toxin that was originally found in soft corals from tropical areas of the Pacific Ocean. Soon after, its occurrence was observed in numerous other marine organisms from the same ecological region. More recently, several analogs of PTX were discovered, remarkably all from species of the dinoflagellate genus Ostreopsis. Since these dinoflagellates are also found in other tropical and even in temperate regions, the formerly unsuspected broad distribution of these toxins was revealed. Toxicological studies with these compounds shows repeatedly low LD50 values in different mammals, revealing an acute toxic effect on several organs, as demonstrated by different routes of exposure. Bioassays tested for some marine invertebrates and evidences from environmental populations exposed to the toxins also give indications of the high impact that these compounds may have on natural food webs. The recognition of its wide distribution coupled with the poisoning effects that these toxins can have on animals and especially on humans have concerned the scientific community. In this paper, we review the current knowledge on the effects of PTX and its analogs on different organisms, exposing the impact that these toxins may have in coastal ecosystems. PMID:20714422

  16. Endpoint distinctiveness facilitates analogical mapping in pigeons.

    PubMed

    Hagmann, Carl Erick; Cook, Robert G

    2015-03-01

    Analogical thinking necessitates mapping shared relations across two separate domains. We investigated whether pigeons could learn faster with ordinal mapping of relations across two physical dimensions (circle size & choice spatial position) relative to random mapping of these relations. Pigeons were trained to relate six circular samples of different sizes to horizontally positioned choice locations in a six alternative matching-to-sample task. Three pigeons were trained in a mapped condition in which circle size mapped directly onto choice spatial position. Three other pigeons were trained in a random condition in which the relations between size and choice position were arbitrarily assigned. The mapped group showed an advantage over the random group in acquiring this task. In a subsequent second phase, relations between the dimensions were ordinally reversed for the mapped group and re-randomized for the random group. There was no difference in how quickly matching accuracy re-emerged in the two groups, although the mapped group eventually performed more accurately. Analyses suggested this mapped advantage was likely due to endpoint distinctiveness and the benefits of proximity errors during choice responding rather than a conceptual or relational advantage attributable to the common or ordinal mapping of the two dimensions. This potential difficulty in mapping relations across dimensions may limit the pigeons' capacity for more advanced types of analogical reasoning. This article is part of a Special Issue entitled: Tribute to Tom Zentall.

  17. The gravitational analog of Faraday's induction law

    NASA Astrophysics Data System (ADS)

    Zile, Daniel; Overduin, James

    2015-04-01

    Michael Faraday, the discoverer of electromagnetic induction, was convinced that there must also be a gravitational analog of this law, and he carried out drop-tower experiments in 1849 to look for the electric current induced in a coil by changes in gravitational flux through the coil. This work, now little remembered, was in some ways the first investigation of what we would now call a unified-field theory. We revisit Faraday's experiments in the light of current knowledge and ask what might be learned if they were to be performed today. We then review the gravitational analog for Faraday's law that arises within the vector (or gravito-electromagnetic) approximation to Einstein's theory of general relativity in the weak-field, low-velocity limit. This law relates spinning masses and induced ``mass currents'' rather than spinning charges and electric currents, but is otherwise remarkably similar to its electromagnetic counterpart. The predicted effects are completely unobservable in everyday settings like those envisioned by Faraday, but are thought to be relevant in astrophysical contexts like the accretion disks around collapsed stars, thus bearing out Faraday's remarkable intuition. Undergraduate student.

  18. Digital and analog gene circuits for biotechnology.

    PubMed

    Roquet, Nathaniel; Lu, Timothy K

    2014-05-01

    Biotechnology offers the promise of valuable chemical production via microbial processing of renewable and inexpensive substrates. Thus far, static metabolic engineering strategies have enabled this field to advance industrial applications. However, the industrial scaling of statically engineered microbes inevitably creates inefficiencies due to variable conditions present in large-scale microbial cultures. Synthetic gene circuits that dynamically sense and regulate different molecules can resolve this issue by enabling cells to continuously adapt to variable conditions. These circuits also have the potential to enable next-generation production programs capable of autonomous transitioning between steps in a bioprocess. Here, we review the design and application of two main classes of dynamic gene circuits, digital and analog, for biotechnology. Within the context of these classes, we also discuss the potential benefits of digital-analog interconversion, memory, and multi-signal integration. Though synthetic gene circuits have largely been applied for cellular computation to date, we envision that utilizing them in biotechnology will enhance the efficiency and scope of biochemical production with living cells.

  19. Martian hillside gullies and icelandic analogs

    NASA Astrophysics Data System (ADS)

    Hartmann, William K.; Thorsteinsson, Thorsteinn; Sigurdsson, Freysteinn

    2003-04-01

    We report observations of Icelandic hillside gully systems that are near duplicates of gullies observed on high-latitude martian hillsides. The best Icelandic analogs involve basaltic talus slopes at the angle of repose, with gully formation by debris flows initiated by ground water saturation, and/or by drainage of water from upslope cliffs. We report not only the existence of Mars analog gullies, but also an erosional sequence of morphologic forms, found both on Mars and in Iceland. The observations support hypotheses calling for creation of martian gullies by aqueous processes. Issues remain whether the water in each case comes only from surficial sources, such as melting of ground ice or snow, or from underground sources such as aquifers that gain surface access in hillsides. Iceland has many examples of the former, but the latter mechanism is not ruled out. Our observations are consistent with the martian debris flow mechanism of F. Costard et al. (2001c, Science295, 110-113), except that classic debris flows begin at midslope more frequently than on Mars. From morphologic observations, we suggest that some martian hillside gully systems not only involve significant evolution by extended erosive activity, but gully formation may occur in episodes, and the time interval since the last episode is considerably less than the time interval needed to erase the gully through normal martian obliteration processes.

  20. Metastatic Insulinoma Managed with Radiolabeled Somatostatin Analog

    PubMed Central

    Costa, Ricardo; Bacchi, Carlos E.; Almeida Filho, Paulo

    2013-01-01

    Insulinoma is a rare pancreatic neuroendocrine tumor. Overproduction of insulin and associated hypoglycemia are hallmark features of this disease. Diagnosis can be made through demonstration of hypoglycemia and elevated plasma levels of insulin or C-Peptide. Metastatic disease can be detected through computerized tomography (CT) scans, magnetic resonance imaging (MRI), and positron emission tomography (PET)/CT. Somatostatin receptor scintigraphy can be used not only to document metastatic disease but also as a predictive marker of the benefit from therapy with radiolabeled somatostatin analog. Unresectable metastatic insulinomas may present as a major therapeutic challenge for the treating physician. When feasible, resection is the mainstay of treatment. Prevention of hypoglycemia is a crucial goal of therapy for unresectable/metastatic tumors. Diazoxide, hydrochlorothiazide, glucagon, and intravenous glucose infusions have been used for glycemic control yielding temporary and inconsistent results. Sandostatin and its long-acting depot forms have occasionally been used in the treatment of Octreoscan-positive insulinomas. Herein, we report a case of metastatic insulinoma with very difficult glycemic control successfully treated with the radiolabeled somatostatin analog lutetium (177LU). PMID:24455330

  1. Antarctic Analog for Dilational Bands on Europa

    NASA Technical Reports Server (NTRS)

    Hurford, T. A.; Brunt, K. M.

    2014-01-01

    Europa's surface shows signs of extension, which is revealed as lithospheric dilation expressed along ridges, dilational bands and ridged bands. Ridges, the most common tectonic feature on Europa, comprise a central crack flanked by two raised banks a few hundred meters high on each side. Together these three classes may represent a continuum of formation. In Tufts' Dilational Model ridge formation is dominated by daily tidal cycling of a crack, which can be superimposed with regional secular dilation. The two sources of dilation can combine to form the various band morphologies observed. New GPS data along a rift on the Ross Ice Shelf, Antarctica is a suitable Earth analog to test the framework of Tufts' Dilational Model. As predicted by Tufts' Dilational Model, tensile failures in the Ross Ice Shelf exhibit secular dilation, upon which a tidal signal can be seen. From this analog we conclude that Tufts' Dilational Model for Europan ridges and bands may be credible and that the secular dilation is most likely from a regional source and not tidally driven.

  2. Operational Lessons Learned from NASA Analog Missions

    NASA Technical Reports Server (NTRS)

    Arnold, Larissa S.

    2010-01-01

    vehicle and system capabilities are required to support the activities? How will the crew and the Earth-based mission control team interact? During the initial phases of manned planetary exploration, one challenge in particular is virtually the same as during the Apollo program: How can scientific return be maximized during a relatively short surface mission? Today, NASA is investigating solutions to these challenges by conducting analog missions. These Earth-based missions possess characteristics that are analogous to missions on the Moon or Mars. These missions are excellent for testing operational concepts, and the design, configuration, and functionality of spacesuits, robots, rovers, and habitats. Analog mission crews test specific techniques and procedures for surface field geology, biological sample collection, and planetary protection. The process of actually working an analog mission reveals a myriad of small details, which either contribute to or impede efficient operations, many of which would never have been thought about otherwise. It also helps to define the suite of tools, containers, and other small equipment that surface explorers will use. This paper focuses on how analog missions have addressed selected operational considerations for future planetary missions.

  3. Experiments on Evolving Software Models of Analog Circuits

    NASA Technical Reports Server (NTRS)

    Lohn, Jason D.

    1999-01-01

    Analog circuits are of great importance in electronic system design since the world is fundamentally analog in nature. While the amount of digital design activity far outpaces that of analog design, most digital systems require analog modules for interfacing with the external world. It was recently estimated that approximately 60% of digital application- specific integrated circuit designs incorporated analog circuits. With challenging analog circuit design problems and few analog design engineers, there are economic reasons for automating the analog design process, especially time-to-market considerations. Techniques for analog circuit design automation began appearing about two decades ago. These methods incorporated heuristics [6], knowledge bases [1], simulated annealing [5], and other algorithms. Efforts using techniques from evolutionary computation began appearing over the last few years. These include the use of genetic algorithms to select electronic component values (for example, the resistance value of a resistor), to select circuit topologies, and to design amplifiers using a limited set of canned topologies [4]. A genetic programming-based analog circuit design system has been demonstrated in which the circuit sizes, component values, and the circuit topologies are determined automatically [3]. The genetic-algorithm systems typically represent circuit structures as vectors of parameters encoded in binary strings, while the genetic programming system manipulates tree data structures.

  4. Study to Allow Access to Pasireotide for Patients Benefiting From Pasireotide Treatment in a Novartis-sponsored Study.

    ClinicalTrials.gov

    2016-10-10

    Cushing's Disease,; Acromegaly,; Neuroendocrine Tumors,; Pituitary Tumors; Ectopic ACTH Secreting (EAS) Tumors,; Dumping Syndrome,; Prostate Cancer,; Melanoma Negative for bRAF,; Melanoma Negative for nRAS

  5. Four-gate transistor analog multiplier circuit

    NASA Technical Reports Server (NTRS)

    Mojarradi, Mohammad M. (Inventor); Blalock, Benjamin (Inventor); Cristoloveanu, Sorin (Inventor); Chen, Suheng (Inventor); Akarvardar, Kerem (Inventor)

    2011-01-01

    A differential output analog multiplier circuit utilizing four G.sup.4-FETs, each source connected to a current source. The four G.sup.4-FETs may be grouped into two pairs of two G.sup.4-FETs each, where one pair has its drains connected to a load, and the other par has its drains connected to another load. The differential output voltage is taken at the two loads. In one embodiment, for each G.sup.4-FET, the first and second junction gates are each connected together, where a first input voltage is applied to the front gates of each pair, and a second input voltage is applied to the first junction gates of each pair. Other embodiments are described and claimed.

  6. Analog VLSI neural network integrated circuits

    NASA Astrophysics Data System (ADS)

    Kub, F. J.; Moon, K. K.; Just, E. A.

    1991-12-01

    Two analog very large scale integration (VLSI) vector matrix multiplier integrated circuit chips were designed, fabricated, and partially tested. They can perform both vector-matrix and matrix-matrix multiplication operations at high speeds. The 32 by 32 vector-matrix multiplier chip and the 128 by 64 vector-matrix multiplier chip were designed to perform 300 million and 3 billion multiplications per second, respectively. An additional circuit that has been developed is a continuous-time adaptive learning circuit. The performance achieved thus far for this circuit is an adaptivity of 28 dB at 300 KHz and 11 dB at 15 MHz. This circuit has demonstrated greater than two orders of magnitude higher frequency of operation than any previous adaptive learning circuit.

  7. Automatic digital-analog impedance plethysmograph

    NASA Astrophysics Data System (ADS)

    Goy, C. B.; Mauro, K. A.; Yanicelli, L. M.; Parodi, N. F.; Gómez López, M. A.; Herrera, M. C.

    2016-04-01

    Venous occlusion plethysmography (VOP) is a traditional method widely used to assess limb blood circulation. One common mode to record VOP is by means of evaluating limb volume changes using impedance plethysmography (IP). In this paper the design and implementation of an automatic digital-analog impedance plethysmograph (ADAIP) for VOP is presented. The system is tested using precision resistances in order to calculate its repeatability. Then its global performance is assessed by means of VOP recordings on the upper and me lower limb of a healthy volunteer. The obtained repeatability was very high (95%), and the VOP recordings where the expected ones. It can be concluded that the whole system performs well and that it is suitable for automatic VOP recording.

  8. Disease Resistance Gene Analogs (RGAs) in Plants

    PubMed Central

    Sekhwal, Manoj Kumar; Li, Pingchuan; Lam, Irene; Wang, Xiue; Cloutier, Sylvie; You, Frank M.

    2015-01-01

    Plants have developed effective mechanisms to recognize and respond to infections caused by pathogens. Plant resistance gene analogs (RGAs), as resistance (R) gene candidates, have conserved domains and motifs that play specific roles in pathogens’ resistance. Well-known RGAs are nucleotide binding site leucine rich repeats, receptor like kinases, and receptor like proteins. Others include pentatricopeptide repeats and apoplastic peroxidases. RGAs can be detected using bioinformatics tools based on their conserved structural features. Thousands of RGAs have been identified from sequenced plant genomes. High-density genome-wide RGA genetic maps are useful for designing diagnostic markers and identifying quantitative trait loci (QTL) or markers associated with plant disease resistance. This review focuses on recent advances in structures and mechanisms of RGAs, and their identification from sequenced genomes using bioinformatics tools. Applications in enhancing fine mapping and cloning of plant disease resistance genes are also discussed. PMID:26287177

  9. Analogy between fluid cavitation and fracture mechanics

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Mullen, R. L.; Braun, M. J.

    1983-01-01

    When the stresses imposed on a fluid are sufficiently large, rupture or cavitation can occur. Such conditions can exist in many two-phase flow applications, such as the choked flows, which can occur in seals and bearings. Nonspherical bubbles with large aspect ratios have been observed in fluids under rapid acceleration and high shear fields. These bubbles are geometrically similar to fracture surface patterns (Griffith crack model) existing in solids. Analogies between crack growth in solid and fluid cavitation are proposed and supported by analysis and observation (photographs). Healing phenomena (void condensation), well accepted in fluid mechanics, have been observed in some polymers and hypothesized in solid mechanics. By drawing on the strengths of the theories of solid mechanics and cavitation, a more complete unified theory can be developed.

  10. Holographic brain: a good analogy gone bad

    NASA Astrophysics Data System (ADS)

    Caulfield, H. John

    2002-07-01

    One way of honoring the world's two greatest holographers is to remove from their field the association with the offbeat world of the holographic mind. Basing itself on analogical musings of two very creative scientists who were themselves not holographers, this 'field' of the holographic brain has strayed far from science and into the absurd. So much absurdity has been written by so many people that the one legitimate study of holographic principle in dolphins has been grouped too often with the nonsense. Here is taken most of the 'target statements' form one book. We could not bear to read them all this closely. We will attempt to determine what tidbit of fact led to the statements and to suggest alternative explanations when there is something to explain.

  11. Analog simulation of stochastic satellite response

    NASA Technical Reports Server (NTRS)

    Huang, T. C.; Das, A.

    1984-01-01

    A numerical study was performed on the effects of stochastic geometry and random environmental torques on the pointing accuracy of spinning and three-axis stabilized satellites. The Euler equations for the motions of satellites yielded the stochastic principal moments and a Fokker-Planck analog simulation was employed to model the response vector of a rigid satellite. White noise inputs were obtained from a random number generator. Attention was given to both fast and slow spin satellites. Responses grew with time in all cases. The growth was initially exponential and eventually reached stable values. In comparison with other theoretical techniques, the Fokker-Planck model detailed the most responses and showed that spin-stabilization is preferable for satellites with low inertial noise levels.

  12. Disease Resistance Gene Analogs (RGAs) in Plants.

    PubMed

    Sekhwal, Manoj Kumar; Li, Pingchuan; Lam, Irene; Wang, Xiue; Cloutier, Sylvie; You, Frank M

    2015-01-01

    Plants have developed effective mechanisms to recognize and respond to infections caused by pathogens. Plant resistance gene analogs (RGAs), as resistance (R) gene candidates, have conserved domains and motifs that play specific roles in pathogens' resistance. Well-known RGAs are nucleotide binding site leucine rich repeats, receptor like kinases, and receptor like proteins. Others include pentatricopeptide repeats and apoplastic peroxidases. RGAs can be detected using bioinformatics tools based on their conserved structural features. Thousands of RGAs have been identified from sequenced plant genomes. High-density genome-wide RGA genetic maps are useful for designing diagnostic markers and identifying quantitative trait loci (QTL) or markers associated with plant disease resistance. This review focuses on recent advances in structures and mechanisms of RGAs, and their identification from sequenced genomes using bioinformatics tools. Applications in enhancing fine mapping and cloning of plant disease resistance genes are also discussed.

  13. Analog VLSI neural network integrated circuits

    NASA Technical Reports Server (NTRS)

    Kub, F. J.; Moon, K. K.; Just, E. A.

    1991-01-01

    Two analog very large scale integration (VLSI) vector matrix multiplier integrated circuit chips were designed, fabricated, and partially tested. They can perform both vector-matrix and matrix-matrix multiplication operations at high speeds. The 32 by 32 vector-matrix multiplier chip and the 128 by 64 vector-matrix multiplier chip were designed to perform 300 million and 3 billion multiplications per second, respectively. An additional circuit that has been developed is a continuous-time adaptive learning circuit. The performance achieved thus far for this circuit is an adaptivity of 28 dB at 300 KHz and 11 dB at 15 MHz. This circuit has demonstrated greater than two orders of magnitude higher frequency of operation than any previous adaptive learning circuit.

  14. Analog VLSI system for active drag reduction

    SciTech Connect

    Gupta, B.; Goodman, R.; Jiang, F.; Tai, Y.C.; Tung, S.; Ho, C.M.

    1996-10-01

    In today`s cost-conscious air transportation industry, fuel costs are a substantial economic concern. Drag reduction is an important way to reduce costs. Even a 5% reduction in drag translates into estimated savings of millions of dollars in fuel costs. Drawing inspiration from the structure of shark skin, the authors are building a system to reduce drag along a surface. Our analog VLSI system interfaces with microfabricated, constant-temperature shear stress sensors. It detects regions of high shear stress and outputs a control signal to activate a microactuator. We are in the process of verifying the actual drag reduction by controlling microactuators in wind tunnel experiments. We are encouraged that an approach similar to one that biology employs provides a very useful contribution to the problem of drag reduction. 9 refs., 21 figs.

  15. Synthetic analogs of bacterial quorum sensors

    DOEpatents

    Iyer, Rashi; Ganguly, Kumkum; Silks, Louis A.

    2011-12-06

    Bacterial quorum-sensing molecule analogs having the following structures: ##STR00001## and methods of reducing bacterial pathogenicity, comprising providing a biological system comprising pathogenic bacteria which produce natural quorum-sensing molecule; providing a synthetic bacterial quorum-sensing molecule having the above structures and introducing the synthetic quorum-sensing molecule into the biological system comprising pathogenic bacteria. Further is provided a method of targeted delivery of an antibiotic, comprising providing a synthetic quorum-sensing molecule; chemically linking the synthetic quorum-sensing molecule to an antibiotic to produce a quorum-sensing molecule-antibiotic conjugate; and introducing the conjugate into a biological system comprising pathogenic bacteria susceptible to the antibiotic.

  16. Synthetic analogs of bacterial quorum sensors

    SciTech Connect

    Iyer, Rashi S.; Ganguly, Kumkum; Silks, Louis A.

    2013-01-08

    Bacterial quorum-sensing molecule analogs having the following structures: ##STR00001## and methods of reducing bacterial pathogenicity, comprising providing a biological system comprising pathogenic bacteria which produce natural quorum-sensing molecule; providing a synthetic bacterial quorum-sensing molecule having the above structures and introducing the synthetic quorum-sensing molecule into the biological system comprising pathogenic bacteria. Further is provided a method of targeted delivery of an antibiotic, comprising providing a synthetic quorum-sensing molecule; chemically linking the synthetic quorum-sensing molecule to an antibiotic to produce a quorum-sensing molecule-antibiotic conjugate; and introducing the conjugate into a biological system comprising pathogenic bacteria susceptible to the antibiotic.

  17. Synthesis and biodistribution of radioiodinated nicotine analogs

    SciTech Connect

    Chan, S.M.; Basmadjian, G.P.; Marten, D.F.; Sadek, S.; Magarian, R.A.; Grunder, J.R.; Ice, R.D.

    1984-01-01

    The authors reported previously on the synthesis and biodistribution of radioiodinated 5-iodonicotine. In their continuous effort to search for a potential brain as well as adrenal medulla imaging agent, the authors synthesized four radioiodinated nicotine analogs. The labeled compounds were prepared by brominating nicotinic acid, and reacting the acylated product with the appropriate amines to give the respective amides which were then reduced with diborane to the amines. I-125 labeling was done by halogen exchange. Biodistribution studies performed in female Sprague-Dawley rats showed that all these compounds were taken up rapidly by the brain and the adrenal. The highest uptake of all these compounds in both organs occurred at 2 minutes after tail vein injections. The organ:blood ratios at 2 minutes and the T/sub 1/3/ (min.) of radioactivity in these organs were compared.

  18. Atwood and Poggendorff: an insightful analogy

    NASA Astrophysics Data System (ADS)

    Coelho, R. L.; Borges, P. F.; Karam, R.

    2016-11-01

    Atwood’s treatise, in which the Atwood machine appears, was published in 1784. About 70 years later, Poggendorff showed experimentally that the weight of an Atwood machine is reduced when it is brought to motion. In the present paper, a twofold connection between this experiment and the Atwood machine is established. Firstly, if the Poggendorff apparatus is taken as an ideal one, the equations of motion of the apparatus coincide with the equations of motion of the compound Atwood machine. Secondly, if the Poggendorff apparatus, which works as a lever, is rebalanced, the equations of this equilibrium provide us with the solution for a compound Atwood machine with the same bodies. This analogy is pedagogically useful because it illustrates a common strategy to transform a dynamic in a static situation improving students’ comprehension of Newton’s laws and equilibrium.

  19. Classical analogs of double electromagnetically induced transparency

    NASA Astrophysics Data System (ADS)

    Bai, Zhengyang; Hang, Chao; Huang, Guoxiang

    2013-03-01

    Double electromagnetically induced transparency (DEIT) in a four-level atomic system with tripod-type energy-level configuration is modeled by using two classical systems. The first is a set of three coupled harmonic oscillators subject to frictional forces and external drives and the second is a set of three coupled RLC circuits with electric resistors and alternating voltage sources. It is shown that both of the two classical systems have absorption spectra of DEIT similar to that of the four-level tripod-type atomic system. These classical analogies provide simple and intuitive physical description of quantum interference processes and can be used to illustrate experimental observations of the DEIT in quantum systems.

  20. ANIMAL ANALOGIES IN FIRST IMPRESSIONS OF FACES.

    PubMed

    Zebrowitz, Leslie A; Wadlinger, Heather A; Luevano, Victor X; White, Benjamin M; Xing, Cai; Zhang, Yi

    2011-08-01

    Analogies between humans and animals based on facial resemblance have a long history. We report evidence for reverse anthropomorphism and the extension of facial stereotypes to lions, foxes, and dogs. In the stereotype extension, more positive traits were attributed to animals judged more attractive than con-specifics; more childlike traits were attributed to those judged more babyfaced. In the reverse anthropomorphism, human faces with more resemblance to lions, ascertained by connectionist modeling of facial metrics, were judged more dominant, cold, and shrewd, controlling attractiveness, babyfaceness, and sex. Faces with more resemblance to Labradors were judged warmer and less shrewd. Resemblance to foxes did not predict impressions. Results for lions and dogs were consistent with trait impressions of these animals and support the species overgeneralization hypothesis that evolutionarily adaptive reactions to particular animals are overgeneralized, with people perceived to have traits associated with animals their faces resemble. Other possible explanations are discussed.

  1. ANIMAL ANALOGIES IN FIRST IMPRESSIONS OF FACES

    PubMed Central

    Zebrowitz, Leslie A.; Wadlinger, Heather A.; Luevano, Victor X.; White, Benjamin M.; Xing, Cai; Zhang, Yi

    2013-01-01

    Analogies between humans and animals based on facial resemblance have a long history. We report evidence for reverse anthropomorphism and the extension of facial stereotypes to lions, foxes, and dogs. In the stereotype extension, more positive traits were attributed to animals judged more attractive than con-specifics; more childlike traits were attributed to those judged more babyfaced. In the reverse anthropomorphism, human faces with more resemblance to lions, ascertained by connectionist modeling of facial metrics, were judged more dominant, cold, and shrewd, controlling attractiveness, babyfaceness, and sex. Faces with more resemblance to Labradors were judged warmer and less shrewd. Resemblance to foxes did not predict impressions. Results for lions and dogs were consistent with trait impressions of these animals and support the species overgeneralization hypothesis that evolutionarily adaptive reactions to particular animals are overgeneralized, with people perceived to have traits associated with animals their faces resemble. Other possible explanations are discussed. PMID:25339791

  2. X-Rays from Green Pea Analogs

    NASA Astrophysics Data System (ADS)

    Brorby, Matthew

    2014-09-01

    X-rays may have contributed to the heating and reionization of the IGM in the early universe. High mass X-ray binaries (HMXB) within small, low-metallicity galaxies are expected to be the main source of X-rays at this time. Since studying these high-redshift galaxies is currently impossible, we turn to local analogs that have the same properties the galaxies in the early are expected to have. A number of recent studies have shown an enhanced number of HMXBs in nearby low metallicity galaxies. We propose to observe a sample of metal-deficient luminous compact galaxies (LCG) in order to determine if the X-ray luminosity is enhanced relative to SFR, thereby providing further evidence to the importance of X-rays in the early universe.

  3. Analog circuit for controlling acoustic transducer arrays

    DOEpatents

    Drumheller, Douglas S.

    1991-01-01

    A simplified ananlog circuit is presented for controlling electromechanical transducer pairs in an acoustic telemetry system. The analog circuit of this invention comprises a single electrical resistor which replaces all of the digital components in a known digital circuit. In accordance with this invention, a first transducer in a transducer pair of array is driven in series with the resistor. The voltage drop across this resistor is then amplified and used to drive the second transducer. The voltage drop across the resistor is proportional and in phase with the current to the transducer. This current is approximately 90 degrees out of phase with the driving voltage to the transducer. This phase shift replaces the digital delay required by the digital control circuit of the prior art.

  4. The optical analogy for vector fields

    SciTech Connect

    Parker, E.N. . Department of Physics University of Chicago, Chicago, IL . Department of Astronomy)

    1991-09-01

    This paper develops the {ital optical} {ital analogy} for a general vector field {bold F}({bold r}), noting that the projection {bold F}{sub {ital s}} of {bold F} onto any surface locus {ital S} of {del}{times}{bold F} can be expressed as the gradient of a scalar, {bold F}{sub {ital s}}={minus}{del}{phi}. It follows that the field lines of {bold F}{sub {ital s}} pass across {ital S} as if refracted by an index of refraction {vert bar}{bold F}{sub {ital s}}{vert bar}. A sufficiently localized maximum in {vert bar}{bold F}{sub {ital s}}{vert bar} refracts the field so as to produce a gap in the field pattern in {ital S}, with the field bifurcating and passing around the sides, rather than across, the maximum. Such a disruption of the field pattern produces a discontinuity in {bold F}. The optical analogy allows the examination of certain aspects of a vector field that are not otherwise readily accessible. In particular, in the cases of a stationary Eulerian flow {bold v} of an ideal fluid and a magnetostatic field {bold B}, the vectors {bold v} and {bold B} have surface loci in common with their curls. The intrinsic discontinuities around local maxima in {vert bar}{bold v}{vert bar} and {vert bar}{bold B}{vert bar} take the form of vortex sheets and current sheets, respectively, the former playing a fundamental role in the development of hydrodynamic turbulence and the latter playing a major role in heating the x-ray coronas of stars and galaxies.

  5. Somatostatin Analog Therapy in Small Cell Lung Cancer.

    PubMed

    Tartarone, Alfredo; Lerose, Rosa; Aieta, Michele

    2016-05-01

    Chemotherapy represents the cornerstone of treatment for patients with small cell lung cancer (SCLC); however, standard therapy has reached a plateau in improving patient survival with overall disappointing results. The demonstration that SCLC expresses neuroendocrine markers, such as somatostatin (SST) receptors, has led to use SST analogs or radiolabeled SST analogs in the treatment of SCLC patients. In the current review, we would focus on the possible role of SST analogs in SCLC. PMID:27067504

  6. Analogy use in naturalistic settings: the influence of audience, emotion, and goals.

    PubMed

    Blanchette, I; Dunbar, K

    2001-07-01

    The ways in which analogy was used in a nonexperimental environment-politics-was investigated. We used the framework developed in analogy research to analyze the selection of analogical sources in political discourse. We took all the analogies reported in newspapers during the final week of a referendum campaign in Canada and analyzed the features of the different analogies used. We identified 234 analogies and analyzed the range over which analogies were used, semantic categories of analogies, goals of the analogizer, and emotional connotation of the analogies. Our results reveal that analogy was frequently used, that over two-thirds of the analogical sources were nonpolitical, and that many of the sources had strong emotional connotations. Furthermore, the goal of the analogizer influenced the selection of sources. We conclude that characteristics of the audience and emotionality of the source analog are important features in the selection of source analogs.

  7. Reynolds analogy for the Rayleigh problem at various flow modes.

    PubMed

    Abramov, A A; Butkovskii, A V

    2016-07-01

    The Reynolds analogy and the extended Reynolds analogy for the Rayleigh problem are considered. For a viscous incompressible fluid we derive the Reynolds analogy as a function of the Prandtl number and the Eckert number. We show that for any positive Eckert number, the Reynolds analogy as a function of the Prandtl number has a maximum. For a monatomic gas in the transitional flow regime, using the direct simulation Monte Carlo method, we investigate the extended Reynolds analogy, i.e., the relation between the shear stress and the energy flux transferred to the boundary surface, at different velocities and temperatures. We find that the extended Reynolds analogy for a rarefied monatomic gas flow with the temperature of the undisturbed gas equal to the surface temperature depends weakly on time and is close to 0.5. We show that at any fixed dimensionless time the extended Reynolds analogy depends on the plate velocity and temperature and undisturbed gas temperature mainly via the Eckert number. For Eckert numbers of the order of unity or less we generalize an extended Reynolds analogy. The generalized Reynolds analogy depends mainly only on dimensionless time for all considered Eckert numbers of the order of unity or less. PMID:27575220

  8. ISS Update: ISTAR -- International Space Station Testbed for Analog Research

    NASA Video Gallery

    NASA Public Affairs Officer Kelly Humphries interviews Sandra Fletcher, EVA Systems Flight Controller. They discuss the International Space Station Testbed for Analog Research (ISTAR) activity that...

  9. Analog solar system model relates celestial bodies spatially

    NASA Technical Reports Server (NTRS)

    Baerg, H. R.

    1966-01-01

    Portable analog planetarium indicates the relative time and space angular locations of the sun and planets. Distance measuring scales, angular direction indicators, and typical probe trajectories are included.

  10. CRC handbook of neurohypophyseal hormone analogs. Volume 2

    SciTech Connect

    Jost, K.; Lebl, M.; Brtnik, F.

    1987-01-01

    This book is discussed in two parts. The Part 1 discusses the: Prohormones and Hormonogens of Neuro-hypophyseal Hormones, Analogs with Inhibitory properties. Analogs with Dissociated and/or High activities. Introduction. Uterotonic Activity. Galactogogic Activity. Pressor Activity. Antidiuretic Activity. References. Part 2 discusses the Other Important Activities. CNS Activities. Corticotropin- and ..beta..-Entriuretic Action. Natriferic Action. References. Practical Use in Human and Veterinary Medicine. Introduction. Methyloxytocin. Deamino-Oxytocin. Cargutocin. Glypressin. Octapressin. Desmopressin. Analogs Clinically Tried But Not Introduced into Production and Routine Clinical Practice. References. Tables of Analogs and Index.

  11. Reynolds analogy for the Rayleigh problem at various flow modes

    NASA Astrophysics Data System (ADS)

    Abramov, A. A.; Butkovskii, A. V.

    2016-07-01

    The Reynolds analogy and the extended Reynolds analogy for the Rayleigh problem are considered. For a viscous incompressible fluid we derive the Reynolds analogy as a function of the Prandtl number and the Eckert number. We show that for any positive Eckert number, the Reynolds analogy as a function of the Prandtl number has a maximum. For a monatomic gas in the transitional flow regime, using the direct simulation Monte Carlo method, we investigate the extended Reynolds analogy, i.e., the relation between the shear stress and the energy flux transferred to the boundary surface, at different velocities and temperatures. We find that the extended Reynolds analogy for a rarefied monatomic gas flow with the temperature of the undisturbed gas equal to the surface temperature depends weakly on time and is close to 0.5. We show that at any fixed dimensionless time the extended Reynolds analogy depends on the plate velocity and temperature and undisturbed gas temperature mainly via the Eckert number. For Eckert numbers of the order of unity or less we generalize an extended Reynolds analogy. The generalized Reynolds analogy depends mainly only on dimensionless time for all considered Eckert numbers of the order of unity or less.

  12. How strategists really think. Tapping the power of analogy.

    PubMed

    Gavetti, Giovanni; Rivkin, Jan W

    2005-04-01

    Leaders tend to be so immersed in the specifics of strategy that they rarely stop to think how much of their reasoning is done by analogy. As a result, they miss useful insights that psychologists and other scientists have generated about analogies' pitfalls. Managers who pay attention to their own analogical thinking will make better strategic decisions and fewer mistakes. Charles Lazarus was inspired by the supermarket when he founded Toys R Us; Intel promoted its low-end chips to avoid becoming like U.S. Steel; and Circuit City created CarMax because it saw the used-car market as analogous to the consumer-electronics market. Each example displays the core elements of analogical reasoning: a novel problem or a new opportunity, a specific prior context that managers deem to be similar in its essentials, and a solution that managers can transfer from its original setting to the new one. Analogical reasoning is a powerful tool for sparking breakthrough ideas. But dangers arise when analogies are built on surface similarities (headlong diversification based on loose analogies played a role in Enron's collapse, for instance). Psychologists have discovered that it's all too easy to overlook the superficiality of analogies. The situation is further complicated by people's tendency to hang on to beliefs even after contrary evidence comes along (a phenomenon known as anchoring) and their tendency to seek only the data that confirm their beliefs (an effect known as the confirmation bias). Four straightforward steps can improve a management team's odds of using an analogy well: Recognize the analogy and identify its purpose; thoroughly understand its source; determine whether the resemblance is more than superficial; and decide whether the original strategy, properly translated, will work in the target industry. PMID:15807039

  13. How strategists really think. Tapping the power of analogy.

    PubMed

    Gavetti, Giovanni; Rivkin, Jan W

    2005-04-01

    Leaders tend to be so immersed in the specifics of strategy that they rarely stop to think how much of their reasoning is done by analogy. As a result, they miss useful insights that psychologists and other scientists have generated about analogies' pitfalls. Managers who pay attention to their own analogical thinking will make better strategic decisions and fewer mistakes. Charles Lazarus was inspired by the supermarket when he founded Toys R Us; Intel promoted its low-end chips to avoid becoming like U.S. Steel; and Circuit City created CarMax because it saw the used-car market as analogous to the consumer-electronics market. Each example displays the core elements of analogical reasoning: a novel problem or a new opportunity, a specific prior context that managers deem to be similar in its essentials, and a solution that managers can transfer from its original setting to the new one. Analogical reasoning is a powerful tool for sparking breakthrough ideas. But dangers arise when analogies are built on surface similarities (headlong diversification based on loose analogies played a role in Enron's collapse, for instance). Psychologists have discovered that it's all too easy to overlook the superficiality of analogies. The situation is further complicated by people's tendency to hang on to beliefs even after contrary evidence comes along (a phenomenon known as anchoring) and their tendency to seek only the data that confirm their beliefs (an effect known as the confirmation bias). Four straightforward steps can improve a management team's odds of using an analogy well: Recognize the analogy and identify its purpose; thoroughly understand its source; determine whether the resemblance is more than superficial; and decide whether the original strategy, properly translated, will work in the target industry.

  14. ANALOG: a program for estimating paleoclimate parameters using the method of modern analogs

    USGS Publications Warehouse

    Schweitzer, Peter N.

    1994-01-01

    Beginning in the 1970s with CLIMAP, paleoclimatologists have been trying to derive quantitative estimates of climatic parameters from the sedimentary record. In general the procedure is to observe the modern distribution of some component of surface sediment that depends on climate, find an empirical relationship between climate and the character of sediments, then extrapolate past climate by studying older sediments in the same way. Initially the empirical relationship between climate and components of the sediment was determined using a multiple regression technique (Imbrie and Kipp, 1971). In these studies sea-floor sediments were examined to determine the percentage of various species of planktonic foraminifera present in them. Supposing that the distribution of foraminiferal assemblages depended strongly on the extremes of annual sea-surface temperature (SST), the foraminiferal assemblages (refined through use of varimax factor analysis) were regressed against the average SST during the coolest and warmest months of the year. The result was a set of transfer functions, equations that could be used to estimate cool and warm SST from the faunal composition of a sediment sample. Assuming that the ecological preference of the species had remained constant throughout the last several hundred thousand years, these transfer functions could be used to estimate SSTs during much of the late Pleistocene. Hutson (1980) and Overpeck, Webb, and Prentice (1985) proposed an alternative approach to estimating paleoclimatic parameters. Their 'method of modern analogs' revolved not around the existence of a few climatically-sensitive faunal assemblages but rather on the expectation that similar climatic regimes should foster similar faunal and floral assemblages. From a large pool of modern samples, those few are selected whose faunal compositions are most similar to a given fossil sample. Paleoclimate estimates are derived using the climatic character of only the most similar

  15. Resonant Tunneling Analog-To-Digital Converter

    NASA Technical Reports Server (NTRS)

    Broekaert, T. P. E.; Seabaugh, A. C.; Hellums, J.; Taddiken, A.; Tang, H.; Teng, J.; vanderWagt, J. P. A.

    1995-01-01

    As sampling rates continue to increase, current analog-to-digital converter (ADC) device technologies will soon reach a practical resolution limit. This limit will most profoundly effect satellite and military systems used, for example, for electronic countermeasures, electronic and signal intelligence, and phased array radar. New device and circuit concepts will be essential for continued progress. We describe a novel, folded architecture ADC which could enable a technological discontinuity in ADC performance. The converter technology is based on the integration of multiple resonant tunneling diodes (RTD) and hetero-junction transistors on an indium phosphide substrate. The RTD consists of a layered semiconductor hetero-structure AlAs/InGaAs/AlAs(2/4/2 nm) clad on either side by heavily doped InGaAs contact layers. Compact quantizers based around the RTD offer a reduction in the number of components and a reduction in the input capacitance Because the component count and capacitance scale with the number of bits N, rather than by 2 (exp n) as in the flash ADC, speed can be significantly increased, A 4-bit 2-GSps quantizer circuit is under development to evaluate the performance potential. Circuit designs for ADC conversion with a resolution of 6-bits at 25GSps may be enabled by the resonant tunneling approach.

  16. Photometric properties of Mars soils analogs

    USGS Publications Warehouse

    Pommerol, A.; Thomas, N.; Jost, B.; Beck, P.; Okubo, C.; McEwen, A.S.

    2013-01-01

    We have measured the bidirectional reflectance of analogs of dry, wet, and frozen Martian soils over a wide range of phase angles in the visible spectral range. All samples were produced from two geologic samples: the standard JSC Mars-1 soil simulant and Hawaiian basaltic sand. In a first step, experiments were conducted with the dry samples to investigate the effects of surface texture. Comparisons with results independently obtained by different teams with similar samples showed a satisfying reproducibility of the photometric measurements as well as a noticeable influence of surface textures resulting from different sample preparation procedures. In a second step, water was introduced to produce wet and frozen samples and their photometry investigated. Optical microscope images of the samples provided information about their microtexture. Liquid water, even in relatively low amount, resulted in the disappearance of the backscattering peak and the appearance of a forward-scattering peak whose intensity increases with the amount of water. Specular reflections only appeared when water was present in an amount large enough to allow water to form a film at the surface of the sample. Icy samples showed a wide variability of photometric properties depending on the physical properties of the water ice. We discuss the implications of these measurements in terms of the expected photometric behavior of the Martian surface, from equatorial to circum-polar regions. In particular, we propose some simple photometric criteria to improve the identification of wet and/or icy soils from multiple observations under different geometries.

  17. Natural CO2 Analogs for Carbon Sequestration

    SciTech Connect

    Scott H. Stevens; B. Scott Tye

    2005-07-31

    The report summarizes research conducted at three naturally occurring geologic CO{sub 2} fields in the US. The fields are natural analogs useful for the design of engineered long-term storage of anthropogenic CO{sub 2} in geologic formations. Geologic, engineering, and operational databases were developed for McElmo Dome in Colorado; St. Johns Dome in Arizona and New Mexico; and Jackson Dome in Mississippi. The three study sites stored a total of 2.4 billion t (46 Tcf) of CO{sub 2} equivalent to 1.5 years of power plant emissions in the US and comparable in size with the largest proposed sequestration projects. The three CO{sub 2} fields offer a scientifically useful range of contrasting geologic settings (carbonate vs. sandstone reservoir; supercritical vs. free gas state; normally pressured vs. overpressured), as well as different stages of commercial development (mostly undeveloped to mature). The current study relied mainly on existing data provided by the CO{sub 2} field operator partners, augmented with new geochemical data. Additional study at these unique natural CO{sub 2} accumulations could further help guide the development of safe and cost-effective design and operation methods for engineered CO{sub 2} storage sites.

  18. The MARS2013 Mars analog mission.

    PubMed

    Groemer, Gernot; Soucek, Alexander; Frischauf, Norbert; Stumptner, Willibald; Ragonig, Christoph; Sams, Sebastian; Bartenstein, Thomas; Häuplik-Meusburger, Sandra; Petrova, Polina; Evetts, Simon; Sivenesan, Chan; Bothe, Claudia; Boyd, Andrea; Dinkelaker, Aline; Dissertori, Markus; Fasching, David; Fischer, Monika; Föger, Daniel; Foresta, Luca; Fritsch, Lukas; Fuchs, Harald; Gautsch, Christoph; Gerard, Stephan; Goetzloff, Linda; Gołebiowska, Izabella; Gorur, Paavan; Groemer, Gerhard; Groll, Petra; Haider, Christian; Haider, Olivia; Hauth, Eva; Hauth, Stefan; Hettrich, Sebastian; Jais, Wolfgang; Jones, Natalie; Taj-Eddine, Kamal; Karl, Alexander; Kauerhoff, Tilo; Khan, Muhammad Shadab; Kjeldsen, Andreas; Klauck, Jan; Losiak, Anna; Luger, Markus; Luger, Thomas; Luger, Ulrich; McArthur, Jane; Moser, Linda; Neuner, Julia; Orgel, Csilla; Ori, Gian Gabriele; Paternesi, Roberta; Peschier, Jarno; Pfeil, Isabella; Prock, Silvia; Radinger, Josef; Ramirez, Barbara; Ramo, Wissam; Rampey, Mike; Sams, Arnold; Sams, Elisabeth; Sandu, Oana; Sans, Alejandra; Sansone, Petra; Scheer, Daniela; Schildhammer, Daniel; Scornet, Quentin; Sejkora, Nina; Stadler, Andrea; Stummer, Florian; Taraba, Michael; Tlustos, Reinhard; Toferer, Ernst; Turetschek, Thomas; Winter, Egon; Zanella-Kux, Katja

    2014-05-01

    We report on the MARS2013 mission, a 4-week Mars analog field test in the northern Sahara. Nineteen experiments were conducted by a field crew in Morocco under simulated martian surface exploration conditions, supervised by a Mission Support Center in Innsbruck, Austria. A Remote Science Support team analyzed field data in near real time, providing planning input for the management of a complex system of field assets; two advanced space suit simulators, four robotic vehicles, an emergency shelter, and a stationary sensor platform in a realistic work flow were coordinated by a Flight Control Team. A dedicated flight planning group, external control centers for rover tele-operations, and a biomedical monitoring team supported the field operations. A 10 min satellite communication delay and other limitations pertinent to human planetary surface activities were introduced. The fields of research for the experiments were geology, human factors, astrobiology, robotics, tele-science, exploration, and operations research. This paper provides an overview of the geological context and environmental conditions of the test site and the mission architecture, in particular the communication infrastructure emulating the signal travel time between Earth and Mars. We report on the operational work flows and the experiments conducted, including a deployable shelter prototype for multiple-day extravehicular activities and contingency situations.

  19. Natural Analog Studies at Pena Blanca, Mexico

    SciTech Connect

    A.M. Simmons

    2005-07-11

    The significance of the Pena Blanca uranium deposits in the State of Chihuahua, Mexico as potential natural analogs for a nuclear waste repository in unsaturated welded tuff was first recognized in the 1980s. In the 1970s, the Pena Blanca region was a major target of uranium exploration and exploitation by the Mexican government. Since then the Nopal I uranium deposit has been studied extensively by researchers in the U.S., Mexico, and Europe. The Nopal I deposit represents an environment similar to that of the proposed high-level radioactive waste repository at Yucca Mountain in many ways. Both are located in semi-arid regions. Both are located in Tertiary rhyolitic tuffs overlying carbonate rocks that have been subjected to basin and range-style tectonic deformation. Both are located in a chemically oxidizing, unsaturated zone 200 m or more above the water table. The alteration of uraninite to secondary minerals at Nopal I may be similar to the alteration of uranium fuel rods in this type of setting. Investigations at Nopal I and in the surrounding Sierra Pena Blanca have included detailed outcrop mapping, hydrologic and isotopic studies of flow and transport, studies of mineral alteration, modeling, and performance assessment.

  20. A fungal analog for newfoundland ediacaran fossils?

    PubMed

    Peterson, Kevin J; Waggoner, Ben; Hagadorn, James W

    2003-02-01

    We propose that some of the more conspicuous Ediacaran fossils from the Avalon Peninsula of Newfoundland, including Aspidella, Charnia, and Charniodiscus, were biologically similar to members of the Kingdom Fungi. These organisms were multicellular or multinuclear, lived below the photic zone, could not move or defoul themselves, did not exhibit taphonomic shrinkage, and were not transported or moved. Aspidella, in particular, appears to exhibit indeterminate growth without a maximum size constraint, and appears to show growth zonations similar to modern mycelia. Other fossils from this deposit exhibit a fractal-like growth pattern. Together, these features falsify algal, lichen, and metazoan interpretations of these fossils, yet reflect characteristics of modern fungal mycelia. We emphasize that although no Mistaken Point fossil appears to be a metazoan, not all of the Mistaken Point taxa, and not all of the Ediacaran organisms in general, can reasonably be interpreted using a fungal analogy. Furthermore, the hypothesis that these fossils were functionally fungus-like need not imply that the organisms were members of the crown-group Fungi. We propose further tests for evaluating both this functional hypothesis and the phylogenetic hypothesis that these organisms were members of the total-group Fungi.

  1. Heavy ion irradiation of astrophysical ice analogs

    NASA Astrophysics Data System (ADS)

    Duarte, Eduardo Seperuelo; Domaracka, Alicja; Boduch, Philippe; Rothard, Hermann; Balanzat, Emmanuel; Dartois, Emmanuel; Pilling, Sergio; Farenzena, Lucio; da Silveira, Enio Frota

    Icy grain mantles consist of small molecules containing hydrogen, carbon, oxygen and nitrogen atoms (e.g. H2O, CO, CO2, NH3). Such ices, present in different astrophysical environments (giant planets satellites, comets, dense clouds, and protoplanetary disks), are subjected to irradiation of different energetic particles: UV radiation, ion bombardment (solar and stellar wind as well as galactic cosmic rays), and secondary electrons due to cosmic ray ionization of H2. The interaction of these particles with astrophysical ice analogs has been the object of research over the last decades. However, there is a lack of information on the effects induced by the heavy ion component of cosmic rays in the electronic energy loss regime. The aim of the present work is to simulate of the astrophysical environment where ice mantles are exposed to the heavy ion cosmic ray irradiation. Sample ice films at 13K were irradiated by nickel ions with energies in the 1-10 MeV/u range and analyzed by means of FTIR spectrometry. Nickel ions were used because their energy deposition is similar to that deposited by iron ions, which are particularly abundant cosmic rays amongst the heaviest ones. In this work the effects caused by nickel ions on condensed gases are studied (destruction and production of molecules as well as associated cross sections, sputtering yields) and compared with respective values for light ions and UV photons.

  2. Vitamin E Analogs as Radiation Response Modifiers

    PubMed Central

    Singh, Pankaj K.; Krishnan, Sunil

    2015-01-01

    The potentially life-threatening effects of total body ionizing radiation exposure have been known for more than a century. Despite considerable advances in our understanding of the effects of radiation over the past six decades, efforts to identify effective radiation countermeasures for use in case of a radiological/nuclear emergency have been largely unsuccessful. Vitamin E is known to have antioxidant properties capable of scavenging free radicals, which have critical roles in radiation injuries. Tocopherols and tocotrienols, vitamin E analogs together known as tocols, have shown promise as radioprotectors. Although the pivotal mechanisms of action of tocols have long been thought to be their antioxidant properties and free radical scavenging activities, other alternative mechanisms have been proposed to drive their activity as radioprotectors. Here we provide a brief overview of the effects of ionizing radiation, the mechanistic mediators of radiation-induced damage, and the need for radiation countermeasures. We further outline the role for, efficacy of, and mechanisms of action of tocols as radioprotectors, and we compare and contrast their efficacy and mode of action with that of another well-studied chemical radioprotector, amifostine. PMID:26366184

  3. Interstellar and Planetary Analogs in the Laboratory

    NASA Technical Reports Server (NTRS)

    Salama, Farid

    2013-01-01

    We present and discuss the unique capabilities of the laboratory facility, COSmIC, that was developed at NASA Ames to investigate the interaction of ionizing radiation (UV, charged particles) with molecular species (neutral molecules, radicals and ions) and carbonaceous grains in the Solar System and in the Interstellar Medium (ISM). COSmIC stands for Cosmic Simulation Chamber, a laboratory chamber where interstellar and planetary analogs are generated, processed and analyzed. It is composed of a pulsed discharge nozzle (PDN) expansion that generates a free jet supersonic expansion in a plasma cavity coupled to two ultrahigh-sensitivity, complementary in situ diagnostics: a cavity ring down spectroscopy (CRDS) system for photonic detection and a Reflectron time-of-flight mass spectrometer (ReTOF-MS) for mass detection. This setup allows the study of molecules, ions and solids under the low temperature and high vacuum conditions that are required to simulate some interstellar, circumstellar and planetary physical environments providing new fundamental insights on the molecular level into the processes that are critical to the chemistry in the ISM, circumstellar and planet forming regions, and on icy objects in the Solar System. Recent laboratory results that were obtained using COSmIC will be discussed, in particular the progress that have been achieved in monitoring in the laboratory the formation of solid particles from their gas-phase molecular precursors in environments as varied as circumstellar outflow and planetary atmospheres.

  4. [Petrological Analysis of Astrophysical Dust Analog Evolution

    NASA Technical Reports Server (NTRS)

    Rietmeijer, Frans J. M.

    1997-01-01

    This project "Petrological analysis of astrophysical dust analog evolution" was initiated to try to understand the vapor phase condensation, and the nature of the reaction products, in circumstellar environments, such as the solar nebula 4,500 Myrs ago, and in the interstellar medium. Telescope-based infrared [IR] spectroscopy offers a broad-scale inventory of the various types of dust in these environments but no details on small-scale variations in terms of chemistry and morphology and petrological phase relationships. Vapor phase condensation in these environments is almost certainly a non-equilibrium process. The main challenge to this research was to document the nature of this process that, based on astrophysical observations, seems to yield compositionally consistent materials. This observation may suggest a predictable character during non-equilibrium condensation. These astrophysical environments include two chemically distinct, that is, oxygen-rich and carbon-rich environments. The former is characterized by silicates the latter by carbon-bearing solids. According to cosmological models of stellar evolution circumstellar dust accreted into protoplanets wherein thermal and/or aqueous processes will alter the dust under initially, non-equilibrium conditions.

  5. Amino acid analogs for tumor imaging

    DOEpatents

    Goodman, M.M.; Shoup, T.

    1998-09-15

    The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is [{sup 18}F]-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an {alpha}-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of {alpha}-aminoisobutyric acid.

  6. Amino acid analogs for tumor imaging

    DOEpatents

    Goodman, Mark M.; Shoup, Timothy

    1998-10-06

    The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is ›.sup.18 F!-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an .alpha.-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of .alpha.-aminoisobutyric acid.

  7. Amino acid analogs for tumor imaging

    DOEpatents

    Goodman, M.M.; Shoup, T.

    1998-10-06

    The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is [{sup 18}F]-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an {alpha}-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of {alpha}-aminoisobutyric acid.

  8. Amino acid analogs for tumor imaging

    DOEpatents

    Goodman, Mark M.; Shoup, Timothy

    1998-09-15

    The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is ›.sup.18 F!-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an .alpha.-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of .alpha.-aminoisobutyric acid.

  9. HERE, THERE, AND EVERYWHEREPublic Science Through Analogy

    NASA Astrophysics Data System (ADS)

    Arcand, Kimberly K.

    2014-06-01

    Here, There, and Everywhere (HTE) is a program that consists of a series of exhibitions, posters, and supporting hands-on activities that utilize analogies in the teaching of science, engineering, and technology to provide multi-generational and family-friendly content in English and Spanish to small community centers, libraries, under-resourced small science centers. The purpose of the program is to connect crosscutting science content (in Earth, atmospheric and planetary sciences and astrophysics) with everyday phenomena. By using different modes of content delivery, from physical exhibits and handouts,to interpretive stations, facilitated activities for educators, and online resources, HTE helps to demonstrate the universality of physical laws and the connection between our everyday world and the universe as a whole to members of the public who may not identify strongly with science. HTE is part of a series of public science projects created and developed by the Education and Public Outreach group at the Chandra X-ray Center. The authors discuss how HTE fits into the lineage of public science outreach that aims to engage the greater public in non-traditional venues for science learning and appreciation, as well as what might be learned about the participants of such projects.

  10. The halogen analogs of thiolated gold nanoclusters

    SciTech Connect

    Jiang, Deen; Walter, Michael

    2012-01-01

    Is it possible to replace all the thiolates in a thiolated gold nanocluster with halogens while still maintaining the geometry and the electronic structure? In this work, we show from density functional theory that such halogen analogs of thiolated gold nanoclusters are highly likely. Using Au{sub 25}X{sub 18}{sup -} as an example, where X = F, Cl, Br, or I replaces -SR, we find that Au{sub 25}Cl{sub 18}{sup -} demonstrates a high similarity to Au{sub 25}(SR){sub 18}{sup -} by showing Au-Cl distances, Cl-Au-Cl angles, band gap, and frontier orbitals similar to those in Au{sub 25}(SR){sub 18}{sup -}. DFT-based global minimization also indicates the energetic preference of staple formation for the Au{sub 25}Cl{sub 18}{sup -} cluster. The similarity between Au{sub m}(SR){sub n} and Au{sub m}X{sub n} could be exploited to make viable Au{sub m}X{sub n} clusters and to predict structures for Au{sub m}(SR){sub n}.

  11. Applying analog integrated circuits for HERO protection

    NASA Technical Reports Server (NTRS)

    Willis, Kenneth E.; Blachowski, Thomas J.

    1994-01-01

    One of the most efficient methods for protecting electro-explosive devices (EED's) from HERO and ESD is to shield the EED in a conducting shell (Faraday cage). Electrical energy is transferred to the bridge by means of a magnetic coupling which passes through a portion of the conducting shell that is made from a magnetically permeable but electrically conducting material. This technique was perfected by ML Aviation, a U.K. company, in the early 80's, and was called a Radio Frequency Attenuation Connector (RFAC). It is now in wide use in the U.K. Previously, the disadvantage of RFAC over more conventional methods was its relatively high cost, largely driven by a thick film hybrid circuit used to switch the primary of the transformer. Recently, through a licensing agreement, this technology has been transferred to the U.S. and significant cost reductions and performance improvements have been achieved by the introduction of analog integrated circuits. An integrated circuit performs the following functions: (1) Chops the DC input to a signal suitable for driving the primary of the transformer; (2) Verifies the input voltage is above a threshold; (3) Verifies the input voltage is valid for a pre set time before enabling the device; (4) Provides thermal protection of the circuit; and (5) Provides an external input for independent logic level enabling of the power transfer mechanism. This paper describes the new RFAC product and its applications.

  12. Biosynthesis of sphinganine-analog mycotoxins.

    PubMed

    Du, L; Zhu, X; Gerber, R; Huffman, J; Lou, L; Jorgenson, J; Yu, F; Zaleta-Rivera, K; Wang, Q

    2008-06-01

    Sphinganine-analog mycotoxins (SAMT) are polyketide-derived natural products produced by a number of plant pathogenic fungi and are among the most economically important mycotoxins. The toxins are structurally similar to sphinganine, a key intermediate in the biosynthesis of ceramides and sphingolipids, and competitive inhibitors for ceramide synthase. The inhibition of ceramide and sphingolipid biosynthesis is associated with several fatal diseases in domestic animals and esophageal cancer and neural tube defects in humans. SAMT contains a highly reduced, acyclic polyketide carbon backbone, which is assembled by a single module polyketide synthase. The biosynthesis of SAMT involves a unique polyketide chain-releasing mechanism, in which a pyridoxal 5'-phosphate-dependent enzyme catalyzes the termination, offloading and elongation of the polyketide chain. This leads to the introduction of a new carbon-carbon bond and an amino group to the polyketide chain. The mechanism is fundamentally different from the thioesterase/cyclase-catalyzed polyketide chain releasing found in bacterial and other fungal polyketide biosynthesis. Genetic data suggest that the ketosynthase domain of the polyketide synthase and the chain-releasing enzyme are important for controlling the final product structure. In addition, several post-polyketide modifications have to take place before SAMT become mature toxins.

  13. Somatostatin analog treatment of acromegaly: new aspects.

    PubMed

    Lamberts, S W; del Pozo, E

    1988-01-01

    Ten acromegalics received daily doses of 200-300 micrograms of a long-acting somatostatin analog, SMS 201-995 (Sandostatin, SMS), for an average of 64 weeks. Basal mean GH values of 44 +/- (SE) 7.8 ng/ml had fallen into the normal range at the end of the observation period (mean 64 weeks). This effect was accompanied by a substantial drop in somatomedin-C values. Reduction of pituitary tumor size could be documented in 3 of 6 patients. Whereas SMS did not affect high plasma PRL in 4 microprolactinoma patients, lactotrophs turned sensitive to this agent in mixed GH/PRL tumors. In a comparative study between SMS and bromocriptine, the former normalized circulating GH in 10 of 17 acromegalics in an acute trial, whereas bromocriptine was effective in only 5. A combination of both substances was effective in 2 of 3 patients who were insensitive to single drug administration. Cultures of GH-secreting tumor cells showed a statistically significant hormone decrease in the medium when exposed to SMS. However, in some instances, a diminution of the GH contents of the tumor cells was also observed, presumably as the basis for intracellular breakdown and clinical tumor shrinkage.

  14. Thermal Conductivity Measurements on consolidated Soil Analogs

    NASA Astrophysics Data System (ADS)

    Seiferlin, K.; Heimberg, M.; Thomas, N.

    2007-08-01

    Heat transport in porous media such as soils and regolith is significantly reduced compared to the properties of compact samples of the same material. The bottle neck for solid state heat transport is the contact area between adjacent grains. For "dry" and unconsolidated materials the contact areas and thus the thermal conductivity are extremely small. Sintering and cementation are two processes that can increase the cross section of interstitial bonds signifcantly. On Mars, cementation can be caused by condensation of water or carbon dioxide ice from the vapor phase, or from salts and minerals that fall out from aqueous solutions. We produced several artificially cemented samples, using small glass beads of uniform size as soil analog. The cementation is achieved by initially molten wax that is mixed with the glass beads while liqiud. The wax freezes preferably at the contact points between grains, thus minimizing surface energy, and consolidates the samples. The thermal conductivity of these samples is then measured in vacuum. We present the results of these measurements and compare them with theoretical models. The observed range of thermal conductivity values can explain some, but not all of the variations in thermal intertia that can be seen in TES remote sensing data.

  15. Semantics by analogy for illustrative volume visualization☆

    PubMed Central

    Gerl, Moritz; Rautek, Peter; Isenberg, Tobias; Gröller, Eduard

    2012-01-01

    We present an interactive graphical approach for the explicit specification of semantics for volume visualization. This explicit and graphical specification of semantics for volumetric features allows us to visually assign meaning to both input and output parameters of the visualization mapping. This is in contrast to the implicit way of specifying semantics using transfer functions. In particular, we demonstrate how to realize a dynamic specification of semantics which allows to flexibly explore a wide range of mappings. Our approach is based on three concepts. First, we use semantic shader augmentation to automatically add rule-based rendering functionality to static visualization mappings in a shader program, while preserving the visual abstraction that the initial shader encodes. With this technique we extend recent developments that define a mapping between data attributes and visual attributes with rules, which are evaluated using fuzzy logic. Second, we let users define the semantics by analogy through brushing on renderings of the data attributes of interest. Third, the rules are specified graphically in an interface that provides visual clues for potential modifications. Together, the presented methods offer a high degree of freedom in the specification and exploration of rule-based mappings and avoid the limitations of a linguistic rule formulation. PMID:23576827

  16. Weathering of Mars - Antarctic analog studies

    NASA Technical Reports Server (NTRS)

    Berkley, J. L.; Drake, M. J.

    1981-01-01

    Subaerial extrusion of lavas above permafrost is proposed as a possible weathering regime leading to the presence of Martian surface fines, and the characteristics of this process are examined through a study of the analogous altered terrestrial basalts from Antarctica. On the basis of mineralogical and petrological analyses of samples obtained from core cuttings recovered by the Dry Valley Drilling Program from rocks predominantly of an aklalic basalt-phonolite suite, it is found that in the absence of liquid water, weathering is geologically slow, and that zeolites predominate over clays as secondary mineral. Of the possible weathering processes proposed for Mars, it is concluded that both subaerial extrusion and subpermafrost intrusion of lavas involving liquid water would be less important volumetrically than the hydrothermal alteration of impact melt sheets if water were present during an intense phase of early bombardment, or than subsequent solid-gas alteration reactions. It is thus predicted that the present Martian fines should contain a major contribution from the ancient crust as typified by the southern cratered highlands, and a lesser contribution from the younger basaltic lavas.

  17. Serial Pixel Analog-to-Digital Converter

    SciTech Connect

    Larson, E D

    2010-02-01

    This method reduces the data path from the counter to the pixel register of the analog-to-digital converter (ADC) from as many as 10 bits to a single bit. The reduction in data path width is accomplished by using a coded serial data stream similar to a pseudo random number (PRN) generator. The resulting encoded pixel data is then decoded into a standard hexadecimal format before storage. The high-speed serial pixel ADC concept is based on the single-slope integrating pixel ADC architecture. Previous work has described a massively parallel pixel readout of a similar architecture. The serial ADC connection is similar to the state-of-the art method with the exception that the pixel ADC register is a shift register and the data path is a single bit. A state-of-the-art individual-pixel ADC uses a single-slope charge integration converter architecture with integral registers and “one-hot” counters. This implies that parallel data bits are routed among the counter and the individual on-chip pixel ADC registers. The data path bit-width to the pixel is therefore equivalent to the pixel ADC bit resolution.

  18. The MARS2013 Mars analog mission.

    PubMed

    Groemer, Gernot; Soucek, Alexander; Frischauf, Norbert; Stumptner, Willibald; Ragonig, Christoph; Sams, Sebastian; Bartenstein, Thomas; Häuplik-Meusburger, Sandra; Petrova, Polina; Evetts, Simon; Sivenesan, Chan; Bothe, Claudia; Boyd, Andrea; Dinkelaker, Aline; Dissertori, Markus; Fasching, David; Fischer, Monika; Föger, Daniel; Foresta, Luca; Fritsch, Lukas; Fuchs, Harald; Gautsch, Christoph; Gerard, Stephan; Goetzloff, Linda; Gołebiowska, Izabella; Gorur, Paavan; Groemer, Gerhard; Groll, Petra; Haider, Christian; Haider, Olivia; Hauth, Eva; Hauth, Stefan; Hettrich, Sebastian; Jais, Wolfgang; Jones, Natalie; Taj-Eddine, Kamal; Karl, Alexander; Kauerhoff, Tilo; Khan, Muhammad Shadab; Kjeldsen, Andreas; Klauck, Jan; Losiak, Anna; Luger, Markus; Luger, Thomas; Luger, Ulrich; McArthur, Jane; Moser, Linda; Neuner, Julia; Orgel, Csilla; Ori, Gian Gabriele; Paternesi, Roberta; Peschier, Jarno; Pfeil, Isabella; Prock, Silvia; Radinger, Josef; Ramirez, Barbara; Ramo, Wissam; Rampey, Mike; Sams, Arnold; Sams, Elisabeth; Sandu, Oana; Sans, Alejandra; Sansone, Petra; Scheer, Daniela; Schildhammer, Daniel; Scornet, Quentin; Sejkora, Nina; Stadler, Andrea; Stummer, Florian; Taraba, Michael; Tlustos, Reinhard; Toferer, Ernst; Turetschek, Thomas; Winter, Egon; Zanella-Kux, Katja

    2014-05-01

    We report on the MARS2013 mission, a 4-week Mars analog field test in the northern Sahara. Nineteen experiments were conducted by a field crew in Morocco under simulated martian surface exploration conditions, supervised by a Mission Support Center in Innsbruck, Austria. A Remote Science Support team analyzed field data in near real time, providing planning input for the management of a complex system of field assets; two advanced space suit simulators, four robotic vehicles, an emergency shelter, and a stationary sensor platform in a realistic work flow were coordinated by a Flight Control Team. A dedicated flight planning group, external control centers for rover tele-operations, and a biomedical monitoring team supported the field operations. A 10 min satellite communication delay and other limitations pertinent to human planetary surface activities were introduced. The fields of research for the experiments were geology, human factors, astrobiology, robotics, tele-science, exploration, and operations research. This paper provides an overview of the geological context and environmental conditions of the test site and the mission architecture, in particular the communication infrastructure emulating the signal travel time between Earth and Mars. We report on the operational work flows and the experiments conducted, including a deployable shelter prototype for multiple-day extravehicular activities and contingency situations. PMID:24823799

  19. Phonon analog of topological nodal semimetals

    NASA Astrophysics Data System (ADS)

    Po, Hoi Chun; Bahri, Yasaman; Vishwanath, Ashvin

    2016-05-01

    Topological band structures in electronic systems like topological insulators and semimetals give rise to highly unusual physical properties. Analogous topological effects have also been discussed in bosonic systems, but the novel phenomena typically occur only when the system is excited by finite-frequency probes. A mapping recently proposed by C. L. Kane and T. C. Lubensky [Nat. Phys. 10, 39 (2014), 10.1038/nphys2835], however, establishes a closer correspondence. It relates the zero-frequency excitations of mechanical systems to topological zero modes of fermions that appear at the edges of an otherwise gapped system. Here we generalize the mapping to systems with an intrinsically gapless bulk. In particular, we construct mechanical counterparts of topological semimetals. The resulting gapless bulk modes are physically distinct from the usual acoustic Goldstone phonons and appear even in the absence of continuous translation invariance. Moreover, the zero-frequency phonon modes feature adjustable momenta and are topologically protected as long as the lattice coordination is unchanged. Such protected soft modes with tunable wave vector may be useful in designing mechanical structures with fault-tolerant properties.

  20. Using Analogies to Prevent Misconceptions about Chemical Equilibrium

    ERIC Educational Resources Information Center

    Sahin Pekmez, Esin

    2010-01-01

    The main purpose of this study was to find the effectiveness of using analogies to prevent misconceptions about chemical equilibrium. Nineteen analogies, which were based on dynamic aspects of chemical equilibrium and application of Le Chatelier's principle, were developed. The participations of this study consisted of 11th grade students (n: 151)…

  1. Analysis of Attention and Analogical Reasoning in Children of Poverty

    ERIC Educational Resources Information Center

    Weatherholt, Tara N.; Harris, Ruby C.; Burns, Barbara M.; Clement, Catherine

    2006-01-01

    This study examined the relationship between specific attentional aspects of processing capacity and analogical reasoning in children from low-income families. 77 children aged 48-77 (M = 56.7) months were assessed on an analogical reasoning task (matrices subtest of the Kaufman Brief Intelligence Test) and on computerized attention tasks designed…

  2. Using Analogies to Improve the Teaching Performance of Preservice Teachers

    ERIC Educational Resources Information Center

    James, Mark C.; Scharmann, Lawrence C.

    2007-01-01

    Prior research in both education and cognitive science has identified analogy making as a powerful tool for explanation as well as a fundamental mechanism for facilitating an individual's construction of knowledge. While a considerable body of research exists focusing on the role analogy plays in learning science concepts, relatively little is…

  3. The interplay of conflict and analogy in multidisciplinary teams.

    PubMed

    Paletz, Susannah B F; Schunn, Christian D; Kim, Kevin H

    2013-01-01

    Creative teamwork in multidisciplinary teams is a topic of interest to cognitive psychologists on the one hand, and to both social and organizational psychologists on the other. However, the interconnections between cognitive and social layers have been rarely explored. Drawing on mental models and dissonance theories, the current study takes a central variable studied by cognitive psychologists-analogy-and examines its relationship to a central variable examined by social psychologists-conflict. In an observational, field study, over 11h of audio-video data from conversations of the Mars Exploration Rover scientists were coded for different types of analogy and micro-conflicts that reveal the character of underlying psychological mechanisms. Two different types of time-lagged logistic models applied to these data revealed asymmetric patterns of associations between analogy and conflict. Within-domain analogies, but not within-discipline or outside-discipline analogies, preceded science and work process conflicts, suggesting that in multidisciplinary teams, representational gaps in very close domains will be more likely to spark conflict. But analogies also occurred in reaction to conflict: Process and negative conflicts, but not task conflicts, preceded within-discipline analogies, but not to within-domain or outside-discipline analogies. This study demonstrates ways in which cognition can be bidirectionally tied to social processes and discourse. PMID:22980920

  4. Introducing Analog Drawing into a Prison Art Education Setting.

    ERIC Educational Resources Information Center

    Yesh, Patrick

    A qualitative research study documents the progress of an adult male art student enrolled in a grade nine art class of adult males in a federal, maximum security penitentiary. Analog drawings were used as part of the curriculum. An analog drawing is a symbolic drawing expressing one's emotions, ideas, and feelings, often used to identify and help…

  5. The Occurrence of Analogies in Elementary School Science Books.

    ERIC Educational Resources Information Center

    Newton, Lynn D.

    2003-01-01

    Investigates the extent to which analogies in instructional science books are provided by authors. Eighty texts available from commercial publishers and intended for use in the elementary school classroom were analyzed. It was found that most of the books did not offer many analogies and fewer than those for older students. (Contains 49…

  6. Where Concepts Meet Percepts: Stimulating Analogical Thought in Children.

    ERIC Educational Resources Information Center

    Flick, Larry

    1991-01-01

    Reports an instructional application of a theory of analogical reasoning. Uses the grinding of a sugar cube as an explanatory-predictive analogy for state transitions of water as a stimulus for promoting associations with other appropriate experiences in elementary school students. (PR)

  7. Analogical Reasoning in the Classroom: Insights from Cognitive Science

    ERIC Educational Resources Information Center

    Vendetti, Michael S.; Matlen, Bryan J.; Richland, Lindsey E.; Bunge, Silvia A.

    2015-01-01

    Applying knowledge from one context to another is a notoriously difficult problem, both for children and adults, but lies at the heart of educational endeavors. Analogical reasoning is a cognitive underpinning of the ability to notice and draw similarities across contexts. Reasoning by analogy is especially challenging for students, who must…

  8. The Effectiveness of Teaching Science with Pictorial Analogies.

    ERIC Educational Resources Information Center

    Lin, Huann-shyang; And Others

    1996-01-01

    This study uses a conceptual problem-solving test to investigate the effect of a series of pictorial analogies on the concepts of density, pressure, and atmospheric pressure in Year Eight classrooms. Findings indicate that students taught with the pictorial analogies scored significantly higher than their counterparts. Low achievers were the most…

  9. Using Self-Generated Analogies in Teaching of Thermodynamics

    ERIC Educational Resources Information Center

    Haglund, Jesper; Jeppsson, Fredrik

    2012-01-01

    Using self-generated analogies has been proposed as a method in a constructivist tradition for students to learn about a new subject, by use of what they previously know. We report on a group exercise on using self-generated analogies to make sense of two thermodynamic processes, reversible adiabatic expansion and free adiabatic expansion of an…

  10. Exploring the Impacts of Analogies on Computer Hardware

    ERIC Educational Resources Information Center

    Dincer, Serkan

    2011-01-01

    In the last few decades, analogy, which is considered as a special case for reasoning, has attracted a great deal of attention from cognitive scientists. Although analogy was rarely applied in previous decades, now it is often considered by educators and researchers as a strategy to provide creative solutions and poetic writing (Paris & Glynn,…

  11. Using Analogies to Overcome Misconceptions: A Technology Course Example.

    ERIC Educational Resources Information Center

    Gokhale, Anu A.

    1996-01-01

    Both a control group and experimental group (23 students each) received a lecture on direct current circuits; the experimental group also participated in a lab using a device explaining an analogy for electric current. The experimental group's posttest scores were much higher, indicating that the analogical device helped overcome student…

  12. Using Analogy to Overcome Misconceptions about Conservation of Matter.

    ERIC Educational Resources Information Center

    Stavy, Ruth

    1991-01-01

    This study (n=192) examined the use of analogical instruction to overcome misconceptions about conservation of matter. Students who understood the concept conservation of matter when iodine was evaporated were able to transfer their understanding to the evaporation of acetone. This indicates that teaching by analogy can be an effective tool in…

  13. Protocol Analysis of Aptitude Differences in Figural Analogy Problem Representation.

    ERIC Educational Resources Information Center

    Schiano, Diane J.

    Individual differences in performance on figural analogy tests are usually attributed to quantitative differences in processing parameters rather than to qualitative differences in the formation and use of representations. Yet aptitude-related differences in categorizing standardized figural analogy problems between high and low scorers have been…

  14. Pictorial Analogies XI: Concentrations and Acidity of Solutions.

    ERIC Educational Resources Information Center

    Fortman, John J.

    1994-01-01

    Presents pictorial analogies of several concepts relating to solutions for chemistry students. These include concentration of solution, strength of solution, supersaturated solution, and conjugate acid-base pairs. Among the examples are comparison of acid strength to percentage of strong soldiers or making supersaturated solution analogous to a…

  15. Implementation Alternatives to Analog Graphic Function Generation: Some Examples.

    ERIC Educational Resources Information Center

    Karayanakis, Nicholas M.

    1988-01-01

    This paper discusses the mechanization of mathematical functions by means of analog electronics. Five different approaches are described which demonstrate the versatility of the analog technique by using parabolic function, exponential decay technique, projectile trajectory, trigonometry, and piecewise linear approximation techniques. (YP)

  16. The interplay of conflict and analogy in multidisciplinary teams.

    PubMed

    Paletz, Susannah B F; Schunn, Christian D; Kim, Kevin H

    2013-01-01

    Creative teamwork in multidisciplinary teams is a topic of interest to cognitive psychologists on the one hand, and to both social and organizational psychologists on the other. However, the interconnections between cognitive and social layers have been rarely explored. Drawing on mental models and dissonance theories, the current study takes a central variable studied by cognitive psychologists-analogy-and examines its relationship to a central variable examined by social psychologists-conflict. In an observational, field study, over 11h of audio-video data from conversations of the Mars Exploration Rover scientists were coded for different types of analogy and micro-conflicts that reveal the character of underlying psychological mechanisms. Two different types of time-lagged logistic models applied to these data revealed asymmetric patterns of associations between analogy and conflict. Within-domain analogies, but not within-discipline or outside-discipline analogies, preceded science and work process conflicts, suggesting that in multidisciplinary teams, representational gaps in very close domains will be more likely to spark conflict. But analogies also occurred in reaction to conflict: Process and negative conflicts, but not task conflicts, preceded within-discipline analogies, but not to within-domain or outside-discipline analogies. This study demonstrates ways in which cognition can be bidirectionally tied to social processes and discourse.

  17. MALISAM: a database of structurally analogous motifs in proteins.

    PubMed

    Cheng, Hua; Kim, Bong-Hyun; Grishin, Nick V

    2008-01-01

    MALISAM (manual alignments for structurally analogous motifs) represents the first database containing pairs of structural analogs and their alignments. To find reliable analogs, we developed an approach based on three ideas. First, an insertion together with a part of the evolutionary core of one domain family (a hybrid motif) is analogous to a similar motif contained within the core of another domain family. Second, a motif at an interface, formed by secondary structural elements (SSEs) contributed by two or more domains or subunits contacting along that interface, is analogous to a similar motif present in the core of a single domain. Third, an artificial protein obtained through selection from random peptides or in sequence design experiments not biased by sequences of a particular homologous family, is analogous to a structurally similar natural protein. Each analogous pair is superimposed and aligned manually, as well as by several commonly used programs. Applications of this database may range from protein evolution studies, e.g. development of remote homology inference tools and discriminators between homologs and analogs, to protein-folding research, since in the absence of evolutionary reasons, similarity between proteins is caused by structural and folding constraints. The database is publicly available at http://prodata.swmed.edu/malisam. PMID:17855399

  18. Using Gravitational Analogies to Introduce Elementary Electrical Field Theory Concepts

    ERIC Educational Resources Information Center

    Saeli, Susan; MacIsaac, Dan

    2007-01-01

    Since electrical field concepts are usually unfamiliar, abstract, and difficult to visualize, conceptual analogies from familiar gravitational phenomena are valuable for teaching. Such analogies emphasize the underlying continuity of field concepts in physics and support the spiral development of student understanding. We find the following four…

  19. Use of Analogy in Learning Physics: The Role of Representations

    ERIC Educational Resources Information Center

    Podolefsky, Noah S.; Finkelstein, Naoh D.

    2006-01-01

    Previous studies have demonstrated that analogies can promote student learning in physics and can be productively taught to students to support their learning, under certain conditions. We build on these studies to explore the use of analogy by students in a large introductory college physics course. In the first large-scale study of its kind, we…

  20. Generation of Spontaneous Analogies by Students Solving Science Problems.

    ERIC Educational Resources Information Center

    Clement, John

    In this study 34 spontaneous analogies produced by 16 college freshmen while solving qualitative physics problems are analyzed. A number of the analogies were invalid in the sense that they led to an incorrect answer from the physicist's point of view. However, many were valid, and a few were powerful in the sense that they seemed not only to help…

  1. 47 CFR 74.705 - TV broadcast analog station protection.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false TV broadcast analog station protection. 74.705... EXPERIMENTAL RADIO, AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.705 TV broadcast analog station protection. (a) The TV...

  2. 47 CFR 74.705 - TV broadcast analog station protection.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false TV broadcast analog station protection. 74.705... EXPERIMENTAL RADIO, AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.705 TV broadcast analog station protection. (a) The TV...

  3. Molecular interactions between (-)-epigallocatechin gallate analogs and pancreatic lipase.

    PubMed

    Wang, Shihui; Sun, Zeya; Dong, Shengzhao; Liu, Yang; Liu, Yun

    2014-01-01

    The molecular interactions between pancreatic lipase (PL) and four tea polyphenols (EGCG analogs), like (-)-epigallocatechin gallate (EGCG), (-)-gallocatechin gallate (GCG), (-)-epicatechin gallate (ECG), and (-)-epigallocatechin (EC), were studied from PL activity, conformation, kinetics and thermodynamics. It was observed that EGCG analogs inhibited PL activity, and their inhibitory rates decreased by the order of EGCG>GCG>ECG>EC. PL activity at first decreased rapidly and then slowly with the increase of EGCG analogs concentrations. α-Helix content of PL secondary structure decreased dependent on EGCG analogs concentration by the order of EGCG>GCG>ECG>EC. EGCG, ECG, and EC could quench PL fluorescence both dynamically and statically, while GCG only quenched statically. EGCG analogs would induce PL self-assembly into complexes and the hydrodynamic radii of the complexes possessed a close relationship with the inhibitory rates. Kinetics analysis showed that EGCG analogs non-competitively inhibited PL activity and did not bind to PL catalytic site. DSC measurement revealed that EGCG analogs decreased the transition midpoint temperature of PL enzyme, suggesting that these compounds reduced PL enzyme thermostability. In vitro renaturation through urea solution indicated that interactions between PL and EGCG analogs were weak and non-covalent. PMID:25365042

  4. Resistance to somatostatin analogs in acromegaly: an evolving concept?

    PubMed

    Gola, M; Bonadonna, S; Mazziotti, G; Amato, G; Giustina, A

    2006-01-01

    The aim of acromegaly treatment is to control the disease by suppressing GH hyperactivity and reducing the size or impeding the growth of the pituitary GH secreting mass. Over recent years, many studies have emphasized the role of SS analogs in the treatment of acromegaly. In fact, SS analogs have been demonstrated to be an effective tool not only in the control of GH hypersecretion but also more recently in the control of tumor growth, in a relevant number of acromegalic patients both as primary or adjunctive treatment. In this context, the therapeutic failure of medical treatment with SS analogs needs to be accurately defined particularly when they are used as primary treatment but also when they are given to patients previously operated upon, since other effective therapeutic options are nowadays available. Current definition of resistance to SS analogs is based on their efficacy to control GH and IGF-I. However, due to the emerging significance of the shrinkage effect of SS analogs on pituitary adenomas as well as to the apparent dissociation between this effect and the biochemical effects of treatment with these analogs, an evolution in the concept of SS resistance is likely to be occurring. In this review, we will discuss the biological basis of the discordance between biochemical and volumetric effects of SS analogs, and we will address the intriguing clinical and therapeutic aspects related to a possible redefinition of the resistance to SS analogs. PMID:16553040

  5. Self-Generated Analogical Models of Respiratory Pathways

    ERIC Educational Resources Information Center

    Lee, Yeung Chung

    2015-01-01

    Self-generated analogical models have emerged recently as alternatives to teacher-supplied analogies and seem to have good potential to promote deep learning and scientific thinking. However, studies of the ways and contexts in which students generate these models are still too limited to allow a fuller appraisal of these models' effectiveness in…

  6. The Impact of Analogy on L3 Reading Comprehension

    ERIC Educational Resources Information Center

    Karami, Hossein; Nodoushan, Mohammad Ali Salmani

    2014-01-01

    Little research has been conducted to investigate the effect of analogy on third language (L3, hereafter) reading comprehension though some experts believe that it has facilitating and debilitating effects on L1 and L2 respectively. This article explores the effect of analogies on reading comprehension of expository texts by students of English as…

  7. Hardware implementation of a discrete-time analog adaptive filter

    SciTech Connect

    Donohoe, G.W.

    1981-01-01

    This paper describes a hardware implementation of a discrete-time adaptive filter using a bucket-brigade device (BBD) tapped analog delay line, analog voltage multipliers and operational amplifier integrators and summing circuits. Some design considerations for this class of circuits are discussed.

  8. Young Children's Analogical Problem Solving: Gaining Insights from Video Displays

    ERIC Educational Resources Information Center

    Chen, Zhe; Siegler, Robert S.

    2013-01-01

    This study examined how toddlers gain insights from source video displays and use the insights to solve analogous problems. Two- to 2.5-year-olds viewed a source video illustrating a problem-solving strategy and then attempted to solve analogous problems. Older but not younger toddlers extracted the problem-solving strategy depicted in the video…

  9. Azastilbene Analogs as Tyrosinase Inhibitors: New Molecules with Depigmenting Potential

    PubMed Central

    Lima, Larissa Lavorato; Lima, Rebeca Mól; da Silva, Annelisa Farah; do Carmo, Antônio Márcio Resende; da Silva, Adilson David; Raposo, Nádia Rezende Barbosa

    2013-01-01

    This research has been an effort to develop synthetic resveratrol analogs in order to improve the depigmenting potential of natural resveratrol. Six resveratrol analogs were synthesized and tested for tyrosinase inhibitory activity in vitro, by qualitative and quantitative steps. The results showed the analog C as being the most powerful tyrosinase inhibitor (IA50 = 65.67 ± 0.60 μg/mL), followed by the analogs B, E, F, A, and D, respectively. The analog C presented a tyrosinase inhibition potential better than natural resveratrol (P < 0.001). The best depigmenting activity was provided by the presence of hydroxyl in the orthoposition on the second phenolic ring. PMID:23476126

  10. NASA HRP Immunology Discipline - Use of Terrestrial Analogs

    NASA Technical Reports Server (NTRS)

    Crucian, Brian

    2014-01-01

    Due to the cost and operational constraints, as well as technical implementation limitations, it is desirous to perform relevant space physiology investigations first in terrestrial 'space analogs'. This is particularly true for initial investigations, which may then provide appropriate focus for subsequent flight investigations, or for mechanistic investigations that simply cannot be performed during spaceflight. Appropriate analog choice is extremely important. There are a wide variety of terrestrial space analogs, each relevant to a particular physiological discipline (or disciplines) and each with a particular fidelity (or lack thereof) to spaceflight, and each with unique operational constraints. The HRP Immunology Discipline is tasked with managing the HRP Risk concerning clinical risk for Astronaut crews related to spaceflight-associated immune dysregulation. Such dysregulation has been documented to occur during spaceflight, and found to persist for the duration of a 6-month ISS mission. Studies continue to characterize the onorbit phenomenon, but it generally consists of diminished immunocyte function, dysregulated cytokine profiles, and persistent herpesvirus reactivation. Causes are thought to synergistically include microgravity, psychological or physiological stress, radiation, and/or circadian misalignment. An appropriate terrestrial analog for immune dysregulation would replicate as many of these influences as possible. Such analogs may include clinostat or bioreactor cell culture (microgravity), hindlimb suspension (stress, fluid shifts, hypokinesis), or human deployment to remote or extreme environments (isolation, stress, circadian). Also, the laboratory setting may be used as an analog, or to augment analogs, such as sleep deprivation/misalignment or human centrifugation to replicate gravitational stress. As an appropriate example of a NASA Disciplines use of Terrestrial space analogs, this talk will discuss spaceflight associated immune

  11. Learning Plate Tectonics Using a Pre-Analogy Step

    NASA Astrophysics Data System (ADS)

    Glesener, G. B.; Sandoval, W. A.

    2011-12-01

    Previous research has shown that children tend to demonstrate lower performance on analogical reasoning tasks at a causal relations level compared to most adults (Gentner & Toupin, 1986). This tendency is an obstacle that geoscience educators must overcome because of the high frequency of analogies used in geoscience pedagogy. In particular, analog models are used to convey complex systems of non-everyday/non-observable events found in nature, such as plate tectonics. Key factors in successful analogical reasoning that have been suggested by researchers include knowledge of the causal relations in the base analog (Brown & Kane, 1988; Gentner, 1988; Gentner & Toupin, 1986), and development of learning strategies and metaconceptual competence(Brown & Kane, 1988). External factors, such as guiding cues and hints have been useful cognitive supports that help students reason through analogical problems (Gick & Holyoak, 1980). Cognitive supports have been seen by researchers to decrease processing demands on retrieval and working memory (Richland, Zur, & Holyoak, 2007). We observed third and fourth graders learning about plate tectonics beginning with a pre-analogy step-a cognitive support activity a student can do before working with an analogy to understand the target. This activity was designed to aid students in developing their understanding of object attributes and relations within an analog model so that more focus can be placed on mapping the corresponding higher-order relations between the base and target. Students learned targeted concepts of plate tectonics, as measured by pre to post gains on items adapted from the Geosciences Concept Inventory. Analyses of classroom interaction showed that students used the object attributes and higher-order relations highlighted in the pre-analogy activity as resources to reason about plate boundaries and plate movement during earthquakes.

  12. The Effect of Analogy-Based Teaching on Students' Achievement and Students' Views about Analogies

    ERIC Educational Resources Information Center

    Genc, Murat

    2013-01-01

    The purpose of this study is to determine the effect of the analogy-based teaching on students' achievement and students' views about analogies. In this research, Solomon group design which is one of the experimental designs, was implemented. The sample of the research consists of 108 students in four 6th grade classes in Turkey. The…

  13. Analogical Matrices in Young Children and Students with Intellectual Disability: Reasoning by Analogy or Reasoning by Association?

    ERIC Educational Resources Information Center

    Denaes, Caroline

    2012-01-01

    Background: Analogical reasoning (AR) is renowned for being a complex activity. Young children tend to reason by association, rather by analogy, and people with intellectual disability present problems of memorization. Both these populations usually show low performances in AR. The present author investigated whether familiar material and external…

  14. Differentiation of Keratinocytes Modulates Skin HPA Analog.

    PubMed

    Wierzbicka, Justyna M; Żmijewski, Michał A; Antoniewicz, Jakub; Sobjanek, Michal; Slominski, Andrzej T

    2017-01-01

    It is well established, that epidermal keratinocytes express functional equivalent of hypothalamus-pituitary-adrenal axis (HPA) in order to respond to changing environment and maintain internal homeostasis. We are presenting data indicating that differentiation of primary neonatal human keratinocytes (HPEKp), induced by prolonged incubation or calcium is accompanied by significant changes in the expression of the elements of skin analog of HPA (sHPA). Expression of CRF, UCN1-3, POMC, ACTH, CRFR1, CRFR2, MC1R, MC2R, and GR (coded by NR3C1 gene) were observed on gene/protein levels along differentiation of keratinocytes in culture with similar pattern seen by immunohistochemistry on full thickness skin biopsies. Expression of CRF was more pronounced in less differentiated keratinocytes, which corresponded to the detection of CRF immunoreactivity preferentially in the stratum basale. POMC expression was enhanced in more differentiated keratinocytes, which corresponded to detection of ACTH immunoreactivity, predominantly in the stratum spinosum and stratum granulosum. Expression of urocortins was also affected by induction of HPEKp differentiation. Immunohistochemical studies showed high prevalence of CRFR1 in well differentiated keratinocytes, while smaller keratinocytes showed predominantly CRFR2 immunoreactivity. MC2R mRNA levels were elevated from days 4 to 8 of in vitro incubation, while MC2R immunoreactivity was the highest in the upper layers of epidermis. Similar changes in mRNA/protein levels of sHPA elements were observed in HPEKp keratinocytes treated with calcium. Summarizing, preferential expression of CRF and POMC (ACTH) by populations of keratinocytes on different stage of differentiation resembles organization of central HPA axis suggesting their distinct role in physiology and pathology of the epidermis. J. Cell. Physiol. 232: 154-166, 2017. © 2016 Wiley Periodicals, Inc.

  15. GnRH analogs in reproductive medicine.

    PubMed

    Hodgen, G D

    1991-03-01

    The uses of gonadotropin releasing hormone (GnRH) analogs in in vitro fertilization (IVF), gamete intrafallopian transfer (GIFT) or related assisted reproductive technologies has advanced rapidly since initial efforts in the early 1980's. By making selective amino acid substitutions, often including the 6 and 10 position, the peptide chemists designed the compounds that we call the GnRH agonists of today. GnRH antagonists possess amino substitutions usually involving positions 1,2,3, 6 and 10, although others may be used. Moreover, recent versions are chemically very sophisticated, often having up to 5 D-amino acids (only L-amino acids occur naturally) and a variety of blocking groups that confer metabolic stability and reduced allergic side-effects. The first available formulation of a GnRH agonist product in the USA was an aqueous preparation for sc injection (usually once or twice daily). It has been studied for several years both in the treatment of prostatic carcinoma and for treatment of children presenting with true precocious puberty. More recently, a depo (monthly) preparation, which microencapulates the GnRH agonist in biodegradable microspheres, received registry approval for treatment of prostatic carcinoma. Also, an implant formulation aimed at chronic treatment indications, as well as nasal delivery products (usually applied multiple times daily) are in development. I will leave specific predictions of the future to those bearing higher powers, except to anticipate that when a safe and effective GnRH antagonist product is developed, it is likely to offer special advantages for IVF/GIFT treatment because of three apparent advantages over GnRH agonist products.

  16. Remote Sensing and Quantization of Analog Sensors

    NASA Technical Reports Server (NTRS)

    Strauss, Karl F.

    2011-01-01

    This method enables sensing and quantization of analog strain gauges. By manufacturing a piezoelectric sensor stack in parallel (physical) with a piezoelectric actuator stack, the capacitance of the sensor stack varies in exact proportion to the exertion applied by the actuator stack. This, in turn, varies the output frequency of the local sensor oscillator. The output, F(sub out), is fed to a phase detector, which is driven by a stable reference, F(sub ref). The output of the phase detector is a square waveform, D(sub out), whose duty cycle, t(sub W), varies in exact proportion according to whether F(sub out) is higher or lower than F(sub ref). In this design, should F(sub out) be precisely equal to F(sub ref), then the waveform has an exact 50/50 duty cycle. The waveform, D(sub out), is of generally very low frequency suitable for safe transmission over long distances without corruption. The active portion of the waveform, t(sub W), gates a remotely located counter, which is driven by a stable oscillator (source) of such frequency as to give sufficient digitization of t(sub W) to the resolution required by the application. The advantage to this scheme is that it negates the most-common, present method of sending either very low level signals (viz. direct output from the sensors) across great distances (anything over one-half meter) or the need to transmit widely varying higher frequencies over significant distances thereby eliminating interference [both in terms of beat frequency generation and in-situ EMI (electromagnetic interference)] caused by ineffective shielding. It also results in a significant reduction in shielding mass.

  17. Resistance to somatostatin analogs in acromegaly.

    PubMed

    Colao, Annamaria; Auriemma, Renata S; Lombardi, Gaetano; Pivonello, Rosario

    2011-04-01

    Somatostatin analogs (SA) are widely used in acromegaly, either as first-line or adjuvant treatment after surgery. First-line treatment with these drugs is generally used in the patients with macroadenomas or in those with clinical conditions so severe as to prevent unsafe reactions during anesthesia. Generally, the response to SA takes into account both control of GH and IGF-I excess, with consequent improvement of clinical symptoms directly related to GH and IGF-I excess, and tumor shrinkage. This latter effect is more prominent in the patients treated first-line and bearing large macroadenomas, but it is also observed in patients with microadenomas, even with little clinical implication. Predictors of response are patients' gender, age, initial GH and IGF-I levels, and tumor mass, as well as adequate expression of somatostatin receptor types 2 and 5, those with the highest affinity for octreotide and lanreotide. Only sporadic cases of somatostatin receptor gene mutation or impaired signaling pathways have been described in GH-secreting tumors so far. The response to SA also depends on treatment duration and dosage of the drug used, so that a definition of resistance based on short-term treatments using low doses of long-acting SA is limited. Current data suggest that response to these drugs is better analyzed taking together biochemical and tumoral effects because only the absence of both responses might be considered as a poor response or resistance. This latter evidence seems to occur in 25% of treated patients after 12 months of currently available long-acting SA. PMID:21123741

  18. Spaceflight Sensorimotor Analogs: Simulating Acute and Adaptive Effects

    NASA Technical Reports Server (NTRS)

    Taylor, Laura C.; Harm, Deborah L.; Kozlovskaya, Inessa; Reschke, Millard F.; Wood, Scott J.

    2009-01-01

    Adaptive changes in sensorimotor function during spaceflight are reflected by spatial disorientation, motion sickness, gaze destabilization and decrements in balance, locomotion and eye-hand coordination that occur during and following transitions between different gravitational states. The purpose of this study was to conduct a meta-synthesis of data from spaceflight analogs to evaluate their effectiveness in simulating adaptive changes in sensorimotor function. METHODS. The analogs under review were categorized as either acute analogs used to simulate performance decrements accompanied with transient changes, or adaptive analogs used to drive sensorimotor learning to altered sensory feedback. The effectiveness of each analog was evaluated in terms of mechanisms of action, magnitude and time course of observed deficits compared to spaceflight data, and the effects of amplitude and exposure duration. RESULTS. Parabolic flight has been used extensively to examine effects of acute variation in gravitational loads, ranging from hypergravity to microgravity. More recently, galvanic vestibular stimulation has been used to elicit acute postural, locomotor and gaze dysfunction by disrupting vestibular afferents. Patient populations, e.g., with bilateral vestibular loss or cerebellar dysfunction, have been proposed to model acute sensorimotor dysfunction. Early research sponsored by NASA involved living onboard rotating rooms, which appeared to approximate the time course of adaptation and post-exposure recovery observed in astronauts following spaceflight. Exposure to different bed-rest paradigms (6 deg head down, dry immersion) result in similar motor deficits to that observed following spaceflight. Shorter adaptive analogs have incorporated virtual reality environments, visual distortion paradigms, exposure to conflicting tilt-translation cues, and exposure to 3Gx centrifugation. As with spaceflight, there is considerable variability in responses to most of the analogs

  19. Source selection for analogical reasoning an empirical approach

    SciTech Connect

    Stubblefield, W.A.; Luger, G.F.

    1996-12-31

    The effectiveness of an analogical reasoner depends upon its ability to select a relevant analogical source. In many problem domains, however, too little is known about target problems to support effective source selection. This paper describes the design and evaluation of SCAVENGER, an analogical reasoner that applies two techniques to this problem: (1) An assumption-based approach to matching that allows properties of candidate sources to match unknown target properties in the absence of evidence to the contrary. (2) The use of empirical learning to improve memory organization based on problem solving experience.

  20. Analysis and analogy in the perception of vowels.

    PubMed

    Remez, Robert E; Fellowes, Jennifer M; Blumenthal, Eva Y; Nagel, Dalia Shoretz

    2003-10-01

    In two experiments, we investigated the creation of conceptual analogies to a contrast between vowels. An ordering procedure was used to determine the reliability of simple sensory and abstract analogies to vowel contrasts composed by naive volunteers. The results indicate that test subjects compose stable and consistent analogies to a meaningless segmental linguistic contrast, some invoking simple and complex relational properties. Although in the literature of psychophysics such facility has been explained as an effect of sensory analysis, the present studies indicate the action of a far subtler and more versatile cognitive function akin to the creation of meaning in figurative language. PMID:14704027

  1. UV IRRADIATION OF AROMATIC NITROGEN HETEROCYCLES IN INTERSTELLAR ICE ANALOGS

    NASA Technical Reports Server (NTRS)

    Elsila, J. E.; Bernstein, M. P.; Sanford, S. A.

    2005-01-01

    Here, we present information on the properties of the ANH quinoline frozen in interstellar water-ice analogs. Quinoline is a two-ring compound structurally analogous to the PAH naphthalene. In this work, binary mixtures of water and quinoline were frozen to create interstellar ice analogs, which were then subjected to ultraviolet photolysis. We will present the infrared spectra of the resulting ices at various temperatures, as well as chromatographic analysis of the residues remaining upon warm-up of these ices to room temperature.

  2. Reasoning by analogy as an aid to heuristic theorem proving.

    NASA Technical Reports Server (NTRS)

    Kling, R. E.

    1972-01-01

    When heuristic problem-solving programs are faced with large data bases that contain numbers of facts far in excess of those needed to solve any particular problem, their performance rapidly deteriorates. In this paper, the correspondence between a new unsolved problem and a previously solved analogous problem is computed and invoked to tailor large data bases to manageable sizes. This paper outlines the design of an algorithm for generating and exploiting analogies between theorems posed to a resolution-logic system. These algorithms are believed to be the first computationally feasible development of reasoning by analogy to be applied to heuristic theorem proving.

  3. Synthesis and biological activity of nifuroxazide and analogs. II.

    PubMed

    Tavares, L C; Chisté, J J; Santos, M G; Penna, T C

    1999-09-01

    Nifuroxazyde and six analogs were synthesized by varying the substitute from the para-position of the benzenic ring and the heteroatom of the heterocyclic ring. The MIC of seven resultant compounds was determined by serial dilutions, testing the ATCC 25923 strain of Staphylococcus aureus. A significant increase in the anti-microbial activity of thyophenic analogs, as compared with furanic and pyrrholic analogs, was observed. In addition, unlike the cyano and hydroxyl groups, the acetyl group promoted anti-microbial activity. PMID:10622109

  4. A radial basis function neurocomputer implemented with analog VLSI circuits

    NASA Technical Reports Server (NTRS)

    Watkins, Steven S.; Chau, Paul M.; Tawel, Raoul

    1992-01-01

    An electronic neurocomputer which implements a radial basis function neural network (RBFNN) is described. The RBFNN is a network that utilizes a radial basis function as the transfer function. The key advantages of RBFNNs over existing neural network architectures include reduced learning time and the ease of VLSI implementation. This neurocomputer is based on an analog/digital hybrid design and has been constructed with both custom analog VLSI circuits and a commercially available digital signal processor. The hybrid architecture is selected because it offers high computational performance while compensating for analog inaccuracies, and it features the ability to model large problems.

  5. Airframe Noise Prediction by Acoustic Analogy: Revisited

    NASA Technical Reports Server (NTRS)

    Farassat, F.; Casper, Jay H.; Tinetti, A.; Dunn, M. H.

    2006-01-01

    The present work follows a recent survey of airframe noise prediction methodologies. In that survey, Lighthill s acoustic analogy was identified as the most prominent analytical basis for current approaches to airframe noise research. Within this approach, a problem is typically modeled with the Ffowcs Williams and Hawkings (FW-H) equation, for which a geometry-independent solution is obtained by means of the use of the free-space Green function (FSGF). Nonetheless, the aeroacoustic literature would suggest some interest in the use of tailored or exact Green s function (EGF) for aerodynamic noise problems involving solid boundaries, in particular, for trailing edge (TE) noise. A study of possible applications of EGF for prediction of broadband noise from turbulent flow over an airfoil surface and the TE is, therefore, the primary topic of the present work. Typically, the applications of EGF in the literature have been limited to TE noise prediction at low Mach numbers assuming that the normal derivative of the pressure vanishes on the airfoil surface. To extend the application of EGF to higher Mach numbers, the uniqueness of the solution of the wave equation when either the Dirichlet or the Neumann boundary condition (BC) is specified on a deformable surface in motion. The solution of Lighthill s equation with either the Dirichlet or the Neumann BC is given for such a surface using EGFs. These solutions involve both surface and volume integrals just like the solution of FW-H equation using FSGF. Insight drawn from this analysis is evoked to discuss the potential application of EGF to broadband noise prediction. It appears that the use of a EGF offers distinct advantages for predicting TE noise of an airfoil when the normal pressure gradient vanishes on the airfoil surface. It is argued that such an approach may also apply to an airfoil in motion. However, for the prediction of broadband noise not directly associated with a trailing edge, the use of EGF does not

  6. Emergent verbal behavior and analogy: skinnerian and linguistic approaches.

    PubMed

    Matos, Maria Amelia; de Lourdes Passos, Maria

    2010-01-01

    The production of verbal operants not previously taught is an important aspect of language productivity. For Skinner, new mands, tacts, and autoclitics result from the recombination of verbal operants. The relation between these mands, tacts, and autoclitics is what linguists call analogy, a grammatical pattern that serves as a foundation on which a speaker might emit new linguistic forms. Analogy appears in linguistics as a regularity principle that characterizes language and has been related to how languages change and also to creativity. The approaches of neogrammarians like Hermann Paul, as well as those of Jespersen and Bloomfield, appear to have influenced Skinner's understanding of verbal creativity. Generalization and stimulus equivalence are behavioral processes related to the generative grammatical behavior described in the analogy model. Linguistic forms and grammatical patterns described in analogy are part of the contingencies of reinforcement that produce generalization and stimulus equivalence. The analysis of verbal behavior needs linguistic analyses of the constituents of linguistic forms and their combination patterns.

  7. NASA Now Minute: Exploring Asteroids: An Analog Mission

    NASA Video Gallery

    NASA’s Extreme Environment Mission Operations, or NEEMO, project leadBill Todd describes this analog mission and how aquanauts living andworking in an undersea habitat are helping NASA prepare ...

  8. FXR agonist activity of conformationally constrained analogs of GW 4064

    SciTech Connect

    Akwabi-Ameyaw, Adwoa; Bass, Jonathan Y.; Caldwell, Richard D.; Caravella, Justin A.; Chen, Lihong; Creech, Katrina L.; Deaton, David N.; Madauss, Kevin P.; Marr, Harry B.; McFadyen, Robert B.; Miller, Aaron B.; Navas, III, Frank; Parks, Derek J.; Spearing, Paul K.; Todd, Dan; Williams, Shawn P.; Wisely, G. Bruce

    2010-09-27

    Two series of conformationally constrained analogs of the FXR agonist GW 4064 1 were prepared. Replacement of the metabolically labile stilbene with either benzothiophene or naphthalene rings led to the identification of potent full agonists 2a and 2g.

  9. Wideband Analog Data System (WADS), system design document

    NASA Technical Reports Server (NTRS)

    Brose, J. F.

    1979-01-01

    The Wideband Analog System (WADS) which performs post flight structural dynamic analysis of wideband FM data recorded during orbital flight tests is defined. Screening, reporting, and plotting steady state and transient wave analysis data are provided by WADS.

  10. FXR agonist activity of conformationally constrained analogs of GW 4064.

    PubMed

    Akwabi-Ameyaw, Adwoa; Bass, Jonathan Y; Caldwell, Richard D; Caravella, Justin A; Chen, Lihong; Creech, Katrina L; Deaton, David N; Madauss, Kevin P; Marr, Harry B; McFadyen, Robert B; Miller, Aaron B; Navas, Frank; Parks, Derek J; Spearing, Paul K; Todd, Dan; Williams, Shawn P; Bruce Wisely, G

    2009-08-15

    Two series of conformationally constrained analogs of the FXR agonist GW 4064 1 were prepared. Replacement of the metabolically labile stilbene with either benzothiophene or naphthalene rings led to the identification of potent full agonists 2a and 2g.

  11. A Review of Terrestrial Analogs for the Moon

    NASA Astrophysics Data System (ADS)

    Garry, W. B.; Needham, D. H.; Young, K. E.; Whelley, P. L.; Bleacher, J. E.

    2016-05-01

    The purpose of this review will be to describe terrestrial geologic analogs that have been used to study lunar geologic processes including: volcanism, impact cratering, structural, and surface processes.

  12. A Novel cooked extruded lentils analog: physical and chemical properties.

    PubMed

    Abu-Ghoush, Mahmoud; Alavi, Sajid; Al-Shathri, Abdulaziz

    2015-07-01

    Developing an extruded lentil analog is our aim. Lentil analog with six formulations were produced using a pilot-scale single (SS) and twin screw (TS) extruders. Texture analysis of lentil analogs prepared for consumption revealed that the products formulated with 60:40 and 70:30 soy: wheat ratios exhibited a significantly higher hardness, adhesiveness and lower springiness as compared to all other treatments. Differential Scanning Calorimeter (DSC) results indicated that all starches in dry blend are completely 100 % gelatinized by extrusion for all treatments at 100 °C. The maximum peak of viscosity for TS was formed after 5.58 min. from the run at 89.9 °C for the best treatment. However, this lentil analog product can provide a high quality lentil which can be used as a substitute for regular lentils.

  13. Young children's analogical problem solving: gaining insights from video displays.

    PubMed

    Chen, Zhe; Siegler, Robert S

    2013-12-01

    This study examined how toddlers gain insights from source video displays and use the insights to solve analogous problems. The sample of 2- and 2.5-year-olds viewed a source video illustrating a problem-solving strategy and then attempted to solve analogous problems. Older, but not younger, toddlers extracted the problem-solving strategy depicted in the video and spontaneously transferred the strategy to solve isomorphic problems. Transfer by analogy from the video was evident only when the video illustrated the complete problem goal structure, including the character's intention and the action needed to achieve a goal. The same action isolated from the problem-solving context did not serve as an effective source analogue. These results illuminate the development of early representation and processes involved in analogical problem solving. Theoretical and educational implications are discussed.

  14. Musical mastery of a Coke™ bottle: Physical modeling by analogy

    NASA Astrophysics Data System (ADS)

    Silverman, Mark P.; Worthy, Elizabeth R.

    1998-02-01

    A Coke™ bottle is modeled in analogy to a resonant LC circuit to obtain a theoretical prediction of the fundamental frequency as a function of the length of the air column. Experimental measurements are in excellent accord with our model.

  15. Student-Generated Analogies: Another Way of Knowing?

    ERIC Educational Resources Information Center

    Pittman, Kim M.

    1999-01-01

    Explores relationships among school students' (n=189) acquisition of meaningful understandings of protein synthesis. Analysis of student-generated analogies revealed unique patterns in students' understandings of this topic. Contains 41 references. (Author/WRM)

  16. Digitoxin and its analogs as novel cancer therapeutics

    PubMed Central

    2012-01-01

    A growing body of evidence indicates that digitoxin cardiac glycoside is a promising anticancer agent when used at therapeutic concentrations. Digitoxin has a prolonged half-life and a well-established clinical profile. New scientific avenues have shown that manipulating the chemical structure of the saccharide moiety of digitoxin leads to synthetic analogs with increased cytotoxic activity. However, the anticancer mechanism of digitoxin or synthetic analogs is still subject to study while concerns about digitoxin's cardiotoxicity preclude its clinical application in cancer therapeutics. This review focuses on digitoxin and its analogs, and their cytotoxicity against cancer cells. Moreover, a new perspective on the pharmacological aspects of digitoxin and its analogs is provided to emphasize new research directions for developing potent chemotherapeutic drugs. PMID:23210930

  17. Further Uses of the Analog Computer as a Teaching Tool

    ERIC Educational Resources Information Center

    Shonle, John I.

    1976-01-01

    Discusses the use of an analog computer oscilloscope to illustrate the transition from underdamped to overdamped for the simple harmonic oscillator, the maximum range for a projectile, and the behavior of charged particles in crossed electric and magnetic fields. (MLH)

  18. Analog compound orthogonal neural network control of robotic manipulators

    NASA Astrophysics Data System (ADS)

    Jun, Ye

    2005-12-01

    An analog compound orthogonal neural network is presented which is based on digital compound orthogonal neural networks. The compound neural network's control performance was investigated as applied to a robot control problem. The analog neural network is a Chebyshev neural network with a high speed-learning rate in an on-line manner. Its control algorithm does not relate to controlled plant models. The analog neural network is used as the feedforward controller, and PD is used as the feedback controller in the control system of robots. The excellent performance in system response, tracking accuracy, and robustness was verified through a simulation experiment applied to a robotic manipulator with friction and nonlinear disturbances. The trajectory tracking control showed results in satisfactory effectiveness. This analog neural controller provides a novel approach for the control of uncertain or unknown systems.

  19. Detectability of Martian Evaporites: Terrestrial Analog Studies with MASTER Data

    NASA Technical Reports Server (NTRS)

    Moersch, J. E.; Farmer, J.; Hook, S. J.

    2000-01-01

    No evaporite mineral deposits have yet been identified on Mars. We present initial results of a terrestrial analog study in Death Valley using airborne hyperspectral data to determine thresholds of detectability for evaporites in current and upcoming Mars datasets.

  20. Synthesis and Evaluation of 2'-Deoxy-2'-Spirodiflurocyclopropyl Nucleoside Analogs.

    PubMed

    Liu, Xiao; Xia, Xueliang; Sun, Chenghai; Lin, Cai; Zhou, Yiqian; Hussain, Muzammal; Tang, Fei; Liu, Lu; Li, Xue; Zhang, Jiancun

    2016-09-01

    The preparation of 2'-deoxy-2'-siprodifluorocyclopropany-lnucleoside analogs has been achieved from α-d-glucose in several steps. The key step in the synthesis was the introduction of the difluorocyclopropane through a difluorocarbene type reaction at the 2'-position. Then, a series of novel 2'-deoxy-2'-spirodifluorocyclopropanyl nucleoside analogs were synthesized using the Vorbrüggen method. All the synthesized nucleosides were characterized and subsequently evaluated against hepatitis C and influenza A virus strains in vitro. PMID:27556785

  1. Analog computer implementation of four instantaneous distortion indices

    NASA Technical Reports Server (NTRS)

    Costakis, W. G.

    1974-01-01

    Dynamic distortion data obtained from inlet engine compatibility test on a J85-GE-13 engine are used to establish the feasibility of using on-line generated indices as control signals. These data are analyzed over time increments of 1.3 seconds on an analog computer. The analog program of four instantaneous distortion indices and their results are presented. A modified approach in determining the extent of distortion is also presented.

  2. Chemical and physical effects in the bulk of cometary analogs

    NASA Technical Reports Server (NTRS)

    Roessler, K.; Benit, Jean; Sauer, M.

    1992-01-01

    KOSI comet simulation experiments were designed as a macroscopic tester for the studies of physicochemical problems inherent to comet bodies. The analog samples consist of H2O and CO2 ice, organic admixtures, mineral dust, and carbon. Two of the fundamental changes the analogs undergo when submitted to 'insolation' by artificial sunlight, i.e., the diffusion of frozen gases and subsequent crust formation and the natural isotopic fractionation, are reported.

  3. FPAA suitability as analog front-end for biosignals

    NASA Astrophysics Data System (ADS)

    Morales, D. P.; García, A.; Palma, A. J.; Meyer-Baese, U.

    2010-04-01

    The use of Field Programmable Analog Arrays (FPAAs) for analog conditioning of electric potentials on the surface of living tissue, such as Electrocardiography (ECG), is presented in this paper. The inherent reconfigurable capability of these devices provides versatility for circuitry dynamic tuning, i.e., changing amplification gains, filters corner frequencies, signal common levels, etc., without interrupting the signal acquisition path. A study of internal circuitry noise sources is presented and some configurations that attenuate noise effects are proposed.

  4. Wideband precision analog telemetry link using digital techniques

    SciTech Connect

    Hearn, W.E.

    1982-10-01

    A highly linear Wideband Analog Fiber Optic Link is described which samples at a 1 MHz rate with 10-bit accuracy and transmits and receives by means of a high speed PDM code. Aliasing and sampling effects are fully suppressed and a nearly Gaussian pulse response is attained with a 2 ..mu..sec risetime. Analog signals are recovered with very low distortion and d.c. drift and a S/N ratio of better than 52 db.

  5. Performance report for Stanford/SLAC Microstore Analog Memory Unit

    SciTech Connect

    Freytag, D.R.; Walker, J.T.

    1984-09-01

    Tests of a newly developed Analog Memory Unit (AMU) are described. The device contains 256 analog storage cells consisting of pass transistors, a storage capacitor and a differential read out buffer. By addressing the storage cells sequentially, the shape of the signal present at the input can be recorded in time. Fast response and good amplitude resolution were the design goals for the development. Measurements on individual devices will be presented and the status of hybridized subsystems containing eight AMUs discussed.

  6. Enhancing students' science text learning and motivation through analogies

    NASA Astrophysics Data System (ADS)

    Carter, Timothy Lewis

    The purpose of the present study was to examine the role that analogies can play in enhancing middle-school students' learning of science text and their motivation to learn it. The students were 73 sixth graders and 85 eighth graders from a rural public school in the southeastern United States. It was hypothesized that the use of constructivist learning methods which involve analogies, particularly analogies enhanced by students' written elaborations or students' drawings, would improve students' text learning and their motivation to learn. Text learning was measured by conceptual understanding, recall, and recognition. Motivation to learn was measured by self-reported activity flow experience. Data were examined through univariate analyses of covariance, content analysis, and Pearson correlations for both immediate and delayed measures. The results indicated that the sixth graders in the analogy condition had significantly higher recall than the sixth graders in the control condition. Based on prior text reading experiences, the sixth graders reported higher levels of flow than the eighth graders. The sixth graders and eighth graders reported equivalent levels of flow in the analogy and control conditions immediately after the actual text study. In the other conditions, where the students were asked to elaborate or draw, the sixth graders reported lower levels of flow suggesting that elaborating and drawing perhaps taxed their limited abilities. Future research should provide higher levels of scaffolding and techniques to encourage the most effective use of written elaboration and drawing when using analogies to learn from science text.

  7. Immune Function Changes during a Spaceflight-Analog Undersea Mission

    NASA Technical Reports Server (NTRS)

    Crucian, Brian; Stowe, Raymond; Mehta, Satish; Quiniarte, Heather; Yetman, Deborah; Pierson, Duane; Sams, Clarence

    2008-01-01

    There is ample evidence to suggest that space flight leads to immune system dysregulation. This may be a result of microgravity, confinement, physiological stress, radiation, environment or other mission-associated factors. It is attractive to utilize ground-based spaceflight analogs as appropriate to investigate this phenomenon. For spaceflight-associated immune dysregulation (SAID), the authors believe the most appropriate analogs might be NEEMO (short duration, Shuttle analog), Antarctic winter-over (long-duration, ISS analog) and the Haughton Mars Project in the Canadian Arctic (intermediate-duration). Each of these analogs replicate isolation, mission-associated stress, disrupted circadian rhythms, and other aspects of flight thought to contribute to SAID. To validate NEEMO as a flight analog with respect to SAID, a pilot study was conducted during the NEEMO-12 and 13 missions during 2007. Assays were performed that assessed immune status, physiological stress and latent viral reactivation. Blood and saliva samples were collected at pre-, mid-, and post-mission timepoints.

  8. Cartographic distortions make dielectric spacetime analog models imperfect mimickers

    NASA Astrophysics Data System (ADS)

    Fathi, Mohsen; Thompson, Robert T.

    2016-06-01

    It is commonly assumed that if the optical metric of a dielectric medium is identical to the metric of a vacuum space-time then light propagation through the dielectric mimics light propagation in the vacuum. However, just as the curved surface of the Earth cannot be mapped into a flat plane without distortion of some surface features, so too is it impossible to project the behavior of light from the vacuum into a dielectric analog residing in Minkowski space-time without introducing distortions. We study the covariance properties of dielectric analog space-times and the kinematics of a congruence of light in the analog, and show how certain features can be faithfully emulated in the analog depending on the choice of projection, but that not all features can be simultaneously emulated without distortion. These findings indicate conceptual weaknesses in the idea of using analog space-times as a basis for transformation optics, and we show that a certain formulation of transformation optics closely related to analog space-times resolves these issues.

  9. Pre-clinical and clinical experiences with novel somatostatin ligands: advantages, disadvantages and new prospects.

    PubMed

    Hofland, L J; van der Hoek, J; Feelders, R; van der Lely, A J; de Herder, W; Lamberts, S W J

    2005-01-01

    in the adenoma cells. A first proof-of-concept trial with the more universal somatostatin-ligand SOM230 in 12 acromegalic patients shows that a single dose of SOM230 is effective in suppressing circulating GH concentrations in a significant larger number of patients compared with octreotide. In animal models, SOM230 has a better effect on GH and IGF-I level with less signs of tachyphylaxis compared with octreotide. Depending on the SSTR expression pattern on neuroendocrine GEP tumors, somatostatin-analogs targeting multiple SSTRs may play a future role in the more long-term control of patients with neuroendocrine GEP tumors. The first clinical trial comparing octreotide and SOM230 is ongoing. However, every advantage has its disadvantage. Targeting multiple SSTR potentially induces more adverse effects as well. Especially, glucose homeostasis might induce new problems in the long-term use of universal ligands. PMID:16625843

  10. Terrestrial stress analogs for spaceflight associated immune system dysregulation.

    PubMed

    Crucian, Brian; Simpson, Richard J; Mehta, Satish; Stowe, Raymond; Chouker, Alexander; Hwang, Shen-An; Actor, Jeffrey K; Salam, Alex P; Pierson, Duane; Sams, Clarence

    2014-07-01

    Recent data indicates that dysregulation of the immune system occurs and persists during spaceflight. Impairment of immunity, especially in conjunction with elevated radiation exposure and limited clinical care, may increase certain health risks during exploration-class deep space missions (i.e. to an asteroid or Mars). Research must thoroughly characterize immune dysregulation in astronauts to enable development of a monitoring strategy and validate any necessary countermeasures. Although the International Space Station affords an excellent platform for on-orbit research, access may be constrained by technical, logistical vehicle or funding limitations. Therefore, terrestrial spaceflight analogs will continue to serve as lower cost, easier access platforms to enable basic human physiology studies. Analog work can triage potential in-flight experiments and thus result in more focused on-orbit studies, enhancing overall research efficiency. Terrestrial space analogs generally replicate some of the physiological or psychological stress responses associated with spaceflight. These include the use of human test subjects in a laboratory setting (i.e. exercise, bed rest, confinement, circadian misalignment) and human remote deployment analogs (Antarctica winterover, undersea, etc.) that incorporate confinement, isolation, extreme environment, physiological mission stress and disrupted circadian rhythms. While bed rest has been used to examine the effects of physical deconditioning, radiation and microgravity may only be simulated in animal or microgravity cell culture (clinorotation) analogs. This article will characterize the array of terrestrial analogs for spaceflight immune dysregulation, the current evidence base for each, and interpret the analog catalog in the context of acute and chronic stress. PMID:24462949

  11. Long-term assessment of prostaglandin analogs and timolol fixed combinations vs prostaglandin analogs monotherapy

    PubMed Central

    Liu, Ai-Wei; Gan, Lin-Yang; Yao, Xiang; Zhou, Jian

    2016-01-01

    AIM To draw a Meta-analysis over the comparison of the intraocular pressure (IOP)-lowering efficacy and safety between the commonly used fixed-combinations of prostaglandin analogs and 0.5% timolol with prostaglandin analogs (PGAs) monotherapy. METHODS After searching the published reports from MEDLINE, EMBASE, the Cochrane Library, all randomized controlled clinical trials (RCTs) comparing the fixed combination of PGAs/timolol therapy (FCs) and PGAs monotherapy with treatment duration at least 6mo were included. The efficacy outcomes were mean diurnal IOP, percentage of participants whose IOP were lower than 18 mm Hg, incidence of visual field change, while the safety outcomes included corneal side effects, hyperemia and eye irritation. The analysis was carried out in RevMan version 5.3 software. RESULTS After six-month medical intervention, the mean diurnal IOP of FCs was lower than PGAs (MD -1.14, 95% CI -1.82 to -0.46, P=0.001); the percentage of target IOP achieving between FCs and PGAs showed no significant difference (RR 1.18, 95% CI 0.97 to 1.43, P=0.10). No statistically significant differences of the incidence of hyperemia (RR 0.67, 95% CI 0.45 to 1.01, P=0.06) and eye irritation (RR 1.20, 95% CI 0.95 to 1.51, P=0.12) between the FCs and PGAs monotherapy were detected. Only one research involved in corneal events, result of this trial revealed no difference between two intervention groups regarding corneal effects (central endothelial cell density, MD -0.20, 95% CI -0.72 to 0.32, P=0.45; central corneal thickness, MD -0.01, 95% CI -0.02 to 0.00, P=0.23). The evaluation of visual field change was not performed due to the limited duration of the trials included in this Meta-analysis. CONCLUSION The long-term efficacy of the FCs overweighed the PGAs monotherapy in lowering IOP, but in the incidence of hyperemia and eye irritation syndromes, the differences are not statically significant. More RCTs with detailed and authentic data over the assessments of

  12. IADE: a system for intelligent automatic design of bioisosteric analogs.

    PubMed

    Ertl, Peter; Lewis, Richard

    2012-11-01

    IADE, a software system supporting molecular modellers through the automatic design of non-classical bioisosteric analogs, scaffold hopping and fragment growing, is presented. The program combines sophisticated cheminformatics functionalities for constructing novel analogs and filtering them based on their drug-likeness and synthetic accessibility using automatic structure-based design capabilities: the best candidates are selected according to their similarity to the template ligand and to their interactions with the protein binding site. IADE works in an iterative manner, improving the fitness of designed molecules in every generation until structures with optimal properties are identified. The program frees molecular modellers from routine, repetitive tasks, allowing them to focus on analysis and evaluation of the automatically designed analogs, considerably enhancing their work efficiency as well as the area of chemical space that can be covered. The performance of IADE is illustrated through a case study of the design of a nonclassical bioisosteric analog of a farnesyltransferase inhibitor--an analog that has won a recent "Design a Molecule" competition.

  13. Overview of the Human Exploration Research Analog (HERA)

    NASA Technical Reports Server (NTRS)

    Neigut, J.

    2015-01-01

    In 2013, the Human Research Program at NASA began developing a new confinement analog specifically for conducting research to investigate the effects of confinement on the human system. The HERA (Human Exploration Research Analog) habitat has been used for both 7 and 14 day missions to date to examine and mitigate exploration risks to enable safe, reliable and productive human space exploration. This presentation will describe how the Flight Analogs Project developed the HERA facility and the infrastructure to suit investigator requirements for confinement research and in the process developed a new approach to analog utilization and a new state of the art analog facility. Details regarding HERA operations will be discussed including specifics on the mission simulation utilized for the current 14-day campaign, the specifics of the facility (total volume, overall size, hardware), and the capabilities available to researchers. The overall operational philosophy, mission fidelity including timeline, schedule pressures and cadence, and development and implementation of mission stressors will be presented. Research conducted to date in the HERA has addressed risks associated with behavioral health and performance, human physiology, as well as human factors. This presentation will conclude with a discussion of future research plans for the HERA, including infrastructure improvements and additional research capabilities planned for the upcoming 30-day missions in 2016.

  14. Analog Experiments on Sulfide Foams in Magmatic Ore Deposits

    NASA Astrophysics Data System (ADS)

    Leitch, A. M.; Dahn, D.; Zavala, K.

    2009-05-01

    Metal sulfides form as an immiscible phase from silicate magmas. Dynamic mingling and unmingling of the two phases is important for the development of economic deposits: mingling promotes enrichment of the sulfide in valuable metals, and subsequent unmingling generates massive sulfide. Analog experiments were carried out to investigate mingling processes in immiscible systems, using oil, water and small beads to represent magma, sulfide liquid and silicate crystals. Stirring or injection led to the formation of a foam of analog sulfide droplets within an analog silicate framework. We propose that the partial collapse of such a foam explains massive sulfide lenses at the Voisey's Bay magmatic sulfide deposit, and that crystallization of silicate crystals in the remaining foam walls generates 'net-textured' ores. In the experiments, solid particles had a profound effect on unmingling: analog sulfide droplets were stably contained within analog crystal-rich magma and did not coalesce. We therefore suggest that 'net' and 'leopard' textures in disseminated sulfides indicate mingling of sulfide with crystal-poor magma, whereas isolated disseminated patches of sulfide indicate mingling with a crystal-rich magma.

  15. Long-duration bed rest as an analog to microgravity.

    PubMed

    Hargens, Alan R; Vico, Laurence

    2016-04-15

    Long-duration bed rest is widely employed to simulate the effects of microgravity on various physiological systems, especially for studies of bone, muscle, and the cardiovascular system. This microgravity analog is also extensively used to develop and test countermeasures to microgravity-altered adaptations to Earth gravity. Initial investigations of bone loss used horizontal bed rest with the view that this model represented the closest approximation to inactivity and minimization of hydrostatic effects, but all Earth-based analogs must contend with the constant force of gravity by adjustment of the G vector. Later concerns about the lack of similarity between headward fluid shifts in space and those with horizontal bed rest encouraged the use of 6 degree head-down tilt (HDT) bed rest as pioneered by Russian investigators. Headward fluid shifts in space may redistribute bone from the legs to the head. At present, HDT bed rest with normal volunteers is the most common analog for microgravity simulation and to test countermeasures for bone loss, muscle and cardiac atrophy, orthostatic intolerance, and reduced muscle strength/exercise capacity. Also, current physiologic countermeasures are focused on long-duration missions such as Mars, so in this review we emphasize HDT bed rest studies with durations of 30 days and longer. However, recent results suggest that the HDT bed rest analog is less representative as an analog for other important physiological problems of long-duration space flight such as fluid shifts, spinal dysfunction and radiation hazards. PMID:26893033

  16. The Acoustic Analogy and Alternative Theories for Jet Noise Prediction

    NASA Technical Reports Server (NTRS)

    Morris, Philip J.; Farassat, F.

    2002-01-01

    This paper describes several methods for the prediction of jet noise. All but one of the noise prediction schemes are based on Lighthill's or Lilley's acoustic analogy while the other is the jet noise generation model recently proposed by Tam and Auriault. In all the approaches some assumptions must be made concerning the statistical properties of the turbulent sources. In each case the characteristic scales of the turbulence are obtained from a solution of the Reynolds-averaged Navier Stokes equation using a k - epsilon turbulence model. It is shown that, for the same level of empiricism, Tam and Auriault's model yields better agreement with experimental noise measurements than the acoustic analogy. It is then shown that this result is not because of some fundamental flaw in the acoustic analogy approach: but, is associated with the assumptions made in the approximation of the turbulent source statistics. If consistent assumptions are made, both the acoustic analogy and Tam and Auriault's model yield identical noise predictions. The paper concludes with a proposal for an acoustic analogy that provides a clearer identification of the equivalent source mechanisms and a discussion of noise prediction issues that remain to be resolved.

  17. Synthesis and bioactivity of 2',3'-benzoabscisic acid analogs.

    PubMed

    Han, Xiaoqiang; Wan, Chuan; Li, Xiuyun; Li, Hong; Yang, Dongyan; Du, Shijie; Xiao, Yumei; Qin, Zhaohai

    2015-06-01

    2',3'-Benzoabscisic acid 4a is significantly more active than (±)-ABA and can be potentially used as a plant growth regulator for agriculture. In this study, six 4a analogs were designed and synthesized. Bioassay showed that 4a displayed greater activity than (±)-ABA and the six analogs produced less inhibition than 4a itself. Specially, some analogs displayed markedly different activities to different physiological and biochemical process, which were largely different from ABA and 4a. Compared to (±)-ABA, 4b and 4c were more effective germination inhibitors for lettuce, but less effective inhibitors for rice elongation. Five-membered analog 5 was higher or slightly weaker in inhibiting Arabidopsis seed germination and rice elongation, respectively, but at least 10 times less effective than (±)-ABA in lettuce seed germination. Dual acid 6 and alkyne acid 20 nearly produced no inhibitory activity for Arabidopsis seed germination, but displayed excellent activity in inhibiting rice seedling growth. The preference of the analogs to different physiology process indicated that they might provide a strategy to develop novel ABA agonists or antagonist and be used as probe to investigate the function of different ABA receptors. PMID:25913114

  18. Membrane Affinity of Platensimycin and Its Dialkylamine Analogs

    PubMed Central

    Rowe, Ian; Guo, Min; Yasmann, Anthony; Cember, Abigail; Sintim, Herman O.; Sukharev, Sergei

    2015-01-01

    Membrane permeability is a desired property in drug design, but there have been difficulties in quantifying the direct drug partitioning into native membranes. Platensimycin (PL) is a new promising antibiotic whose biosynthetic production is costly. Six dialkylamine analogs of PL were synthesized with identical pharmacophores but different side chains; five of them were found inactive. To address the possibility that their activity is limited by the permeation step, we calculated polarity, measured surface activity and the ability to insert into the phospholipid monolayers. The partitioning of PL and the analogs into the cytoplasmic membrane of E. coli was assessed by activation curve shifts of a re-engineered mechanosensitive channel, MscS, in patch-clamp experiments. Despite predicted differences in polarity, the affinities to lipid monolayers and native membranes were comparable for most of the analogs. For PL and the di-myrtenyl analog QD-11, both carrying bulky sidechains, the affinity for the native membrane was lower than for monolayers (half-membranes), signifying that intercalation must overcome the lateral pressure of the bilayer. We conclude that the biological activity among the studied PL analogs is unlikely to be limited by their membrane permeability. We also discuss the capacity of endogenous tension-activated channels to detect asymmetric partitioning of exogenous substances into the native bacterial membrane and the different contributions to the thermodynamic force which drives permeation. PMID:26247942

  19. Novel trypanocidal analogs of 5'-(methylthio)-adenosine.

    PubMed

    Sufrin, Janice R; Spiess, Arthur J; Marasco, Canio J; Rattendi, Donna; Bacchi, Cyrus J

    2008-01-01

    The purine nucleoside 5'-deoxy-5'-(hydroxyethylthio)-adenosine (HETA) is an analog of the polyamine pathway metabolite 5'-deoxy-5'-(methylthio)-adenosine (MTA). HETA is a lead structure for the ongoing development of selectively targeted trypanocidal agents. Thirteen novel HETA analogs were synthesized and examined for their in vitro trypanocidal activities against bloodstream forms of Trypanosoma brucei brucei LAB 110 EATRO and at least one drug-resistant Trypanosoma brucei rhodesiense clinical isolate. New compounds were also assessed in a cell-free assay for their activities as substrates of trypanosome MTA phosphorylase. The most potent analog in this group was 5'-deoxy-5'-(hydroxyethylthio)-tubercidin, whose in vitro cytotoxicity (50% inhibitory concentration [IC50], 10 nM) is 45 times greater than that of HETA (IC50, 450 nM) against pentamidine-resistant clinical isolate KETRI 269. Structure-activity analyses indicate that the enzymatic cleavage of HETA analogs by trypanosome MTA phosphorylase is not an absolute requirement for trypanocidal activity. This suggests that additional biochemical mechanisms are associated with the trypanocidal effects of HETA and its analogs.

  20. Fuzzy classifier for fault diagnosis in analog electronic circuits.

    PubMed

    Kumar, Ashwani; Singh, A P

    2013-11-01

    Many studies have presented different approaches for the fault diagnosis with fault models having ± 50% variation in the component values in analog electronic circuits. There is still a need of the approaches which provide the fault diagnosis with the variation in the component value below ± 50%. A new single and multiple fault diagnosis technique for soft faults in analog electronic circuit using fuzzy classifier has been proposed in this paper. This technique uses the simulation before test (SBT) approach by analyzing the frequency response of the analog circuit under faulty and fault free conditions. Three signature parameters peak gain, frequency and phase associated with peak gain, of the frequency response of the analog circuit are observed and extracted such that they give unique values for faulty and fault free configuration of the circuit. The single and double fault models with the component variations from ± 10% to ± 50% are considered. The fuzzy classifier along the classification of faults gives the estimated component value under faulty and faultfree conditions. The proposed method is validated using simulated data and the real time data for a benchmark analog circuit. The comparative analysis is also presented for both the validations.

  1. The Acoustic Analogy and Alternative Theories for Jet Noise Prediction

    NASA Technical Reports Server (NTRS)

    Morris, Philip J.; Farassat, F.; Morris, Philip J.

    2002-01-01

    This paper describes several methods for the prediction of jet noise. All but one of the noise prediction schemes are based on Lighthill's or Lilley's acoustic analogy while the other is the jet noise generation model recently proposed by Tam and Auriault. In all the approaches some assumptions must be made concerning the statistical properties of the turbulent sources. In each case the characteristic scales of the turbulence are obtained from a solution of the Reynolds-averaged Navier Stokes equation using a k-epsilon turbulence model. It is shown that, for the same level of empiricism, Tam and Auriault's model yields better agreement with experimental noise measurements than the acoustic analogy. It is then shown that this result is not because of some fundamental flaw in the acoustic analogy approach: but, is associated with the assumptions made in the approximation of the turbulent source statistics. If consistent assumptions are made, both the acoustic analogy and Tam and Auriault's model yield identical noise predictions. The paper concludes with a proposal for an acoustic analogy that provides a clearer identification of the equivalent source mechanisms and a discussion of noise prediction issues that remain to be resolved.

  2. Acoustic Analogy and Alternative Theories for Jet Noise Prediction

    NASA Technical Reports Server (NTRS)

    Morris, Philip J.; Farassat, F.

    2002-01-01

    Several methods for the prediction of jet noise are described. All but one of the noise prediction schemes are based on Lighthill's or Lilley's acoustic analogy, whereas the other is the jet noise generation model recently proposed by Tam and Auriault. In all of the approaches, some assumptions must be made concerning the statistical properties of the turbulent sources. In each case the characteristic scales of the turbulence are obtained from a solution of the Reynolds-averaged Navier-Stokes equation using a kappa-sigma turbulence model. It is shown that, for the same level of empiricism, Tam and Auriault's model yields better agreement with experimental noise measurements than the acoustic analogy. It is then shown that this result is not because of some fundamental flaw in the acoustic analogy approach, but instead is associated with the assumptions made in the approximation of the turbulent source statistics. If consistent assumptions are made, both the acoustic analogy and Tam and Auriault's model yield identical noise predictions. In conclusion, a proposal is presented for an acoustic analogy that provides a clearer identification of the equivalent source mechanisms, as is a discussion of noise prediction issues that remain to be resolved.

  3. Analogy learning and the performance of motor skills under pressure.

    PubMed

    Lam, Wing Kai; Maxwell, Jon P; Masters, Richard

    2009-06-01

    The efficacy of analogical instruction, relative to explicit instruction, for the acquisition of a complex motor skill and subsequent performance under pressure was investigated using a modified (seated) basketball shooting task. Differences in attentional resource allocation associated with analogy and explicit learning were also examined using probe reaction times (PRT). Access to task-relevant explicit (declarative) knowledge was assessed. The analogy and explicit learning groups performed equally well during learning and delayed retention tests. The explicit group experienced a drop in performance during a pressured transfer test, relative to their performance during a preceding retention test. However, the analogy group's performance was unaffected by the pressure manipulation. Results from PRTs suggested that both groups allocated equal amounts of attentional resources to the task throughout learning and test trials. Analogy learners had significantly less access to rules about the mechanics of their movements, relative to explicit learners. The results are interpreted in the context of Eysenck and Calvo's (1992) processing efficiency theory and Masters's (1992) theory of reinvestment.

  4. Comparison of analog and digital transceiver systems for MR imaging.

    PubMed

    Hashimoto, Seitaro; Kose, Katsumi; Haishi, Tomoyuki

    2014-01-01

    We critically evaluated analog and digital transceivers for magnetic resonance (MR) imaging systems under identical experimental conditions to identify and compare their advantages and disadvantages. MR imaging experiments were performed using a 4.74-tesla vertical-bore superconducting magnet and a high sensitivity gradient coil probe. We acquired 3-dimensional spin echo images of a kumquat with and without using a gain-stepping scan technique to extend the dynamic range of the receiver systems. The acquired MR images clearly demonstrated nearly identical image quality for both transceiver systems, but DC and ghosting artifacts were obtained for the analog transceiver system. We therefore concluded that digital transceivers have several advantages over the analog transceivers.

  5. INTERSTELLAR ANALOGS FROM DEFECTIVE CARBON NANOSTRUCTURES ACCOUNT FOR INTERSTELLAR EXTINCTION

    SciTech Connect

    Tan, Zhenquan; Abe, Hiroya; Sato, Kazuyoshi; Ohara, Satoshi; Chihara, Hiroki; Koike, Chiyoe; Kaneko, Kenji

    2010-11-15

    Because interstellar dust is closely related to the evolution of matter in the galactic environment and many other astrophysical phenomena, the laboratory synthesis of interstellar dust analogs has received significant attention over the past decade. To simulate the ultraviolet (UV) interstellar extinction feature at 217.5 nm originating from carbonaceous interstellar dust, many reports focused on the UV absorption properties of laboratory-synthesized interstellar dust analogs. However, no general relation has been established between UV interstellar extinction and artificial interstellar dust analogs. Here, we show that defective carbon nanostructures prepared by high-energy collisions exhibit a UV absorption feature at 220 nm which we suggest accounts for the UV interstellar extinction at 217.5 nm. The morphology of some carbon nanostructures is similar to that of nanocarbons discovered in the Allende meteorite. The similarity between the absorption feature of the defective carbon nanostructures and UV interstellar extinction indicates a strong correlation between the defective carbon nanostructures and interstellar dust.

  6. Synthesis and biological activity of Wuweizisu C and analogs.

    PubMed

    Chang, J B; Wang, Q; Li, Y F

    2009-01-01

    Lignans are widely distributed in nature. The earliest recorded medicinal use of lignans dated back to over 1000 years ago. Lignan-rich plant products were also active ingredients in Chinese and Japanese folk medicines for the treatment of various diseases. The dried root and stem of this plant are listed in the Chinese pharmacopoeia for the treatment of rheumatoid arthritis, gastric, duodenal ulcers and many other diseases. This review highlights synthetic strategies for the Wuweizisu C analogs and the important pharmacological activities as well as therapeutic findings related to the treatment of HBV and other diseases. Notably a significant and ongoing project on Wuweizisu C and its analogs has led to the discovery and development of two potent derivatives alpha-DDB and BICYCLOL which are currently in clinical trials against HBV, especially in lowering elevated SGPT levels. Further design, synthesis, and evaluation of Wuweizisu C analogs are discussed.

  7. Comparison of analog and digital transceiver systems for MR imaging.

    PubMed

    Hashimoto, Seitaro; Kose, Katsumi; Haishi, Tomoyuki

    2014-01-01

    We critically evaluated analog and digital transceivers for magnetic resonance (MR) imaging systems under identical experimental conditions to identify and compare their advantages and disadvantages. MR imaging experiments were performed using a 4.74-tesla vertical-bore superconducting magnet and a high sensitivity gradient coil probe. We acquired 3-dimensional spin echo images of a kumquat with and without using a gain-stepping scan technique to extend the dynamic range of the receiver systems. The acquired MR images clearly demonstrated nearly identical image quality for both transceiver systems, but DC and ghosting artifacts were obtained for the analog transceiver system. We therefore concluded that digital transceivers have several advantages over the analog transceivers. PMID:25167877

  8. Analogical thinking in ecology: looking beyond disciplinary boundaries.

    PubMed

    Colyvan, Mark; Ginzburg, Lev R

    2010-06-01

    We consider several ways in which a good understanding of modern techniques and principles in physics can elucidate ecology, and we focus on analogical reasoning between these two branches of science. Analogical reasoning requires an understanding of both sciences and an appreciation of the similarities and points of contact between the two. In the current ecological literature on the relationship between ecology and physics, there has been some misunderstanding about the nature of modern physics and its methods. Physics is seen as being much cleaner and tidier than ecology. When compared to this idealized, fictional version of physics, ecology looks very different, and the prospect of ecology and physics learning from one another is questionable. We argue that physics, once properly understood, is more like ecology than ecologists have thus far appreciated. Physicists and ecologists can and do learn from each other, and, in this paper, we outline how analogical reasoning can facilitate such exchanges.

  9. Mental arithmetic activates analogic representations of internally generated sums.

    PubMed

    Kallai, Arava Y; Schunn, Christian D; Fiez, Julie A

    2012-08-01

    The internal representation of numbers generated during calculation has received little attention. Much of the mathematics learning literature focuses on symbolic retrieval of math facts; in contrast, we critically test the hypothesis that internally generated numbers are represented analogically, using an approximate number system. In an fMRI study, the spontaneous processing of arithmetical expressions was tested. Participants passively viewed a sequence of double-digit addition expressions that summed to the same number. Adaptation was found in number-related regions in a fronto-parietal network. Following adaptation, arrays of dots were introduced, differing in their numerical distance from the sum of the addition expressions. Activation in voxels that showed adaptation to a repeated sum was also sensitive to the distance of the dot quantity from the sum. We conclude that participants exhibited adaptation to an internally generated number, that adapted representations were analogic in nature, and that these analogic representations may undergird arithmetic calculation. PMID:22732492

  10. Ethnographic analogy, the comparative method, and archaeological special pleading.

    PubMed

    Currie, Adrian

    2016-02-01

    Ethnographic analogy, the use of comparative data from anthropology to inform reconstructions of past human societies, has a troubled history. Archaeologists often express concern about, or outright reject, the practice--and sometimes do so in problematically general terms. This is odd, as (or so I argue) the use of comparative data in archaeology is the same pattern of reasoning as the 'comparative method' in biology, which is a well-developed and robust set of inferences which play a central role in discovering the biological past. In pointing out this continuity, I argue that there is no 'special pleading' on the part of archaeologists in this regard: biologists must overcome analogous epistemic difficulties in their use of comparative data. I then go on to emphasize the local, empirically tractable ways in which particular ethnographic analogies may be licensed. PMID:26774072

  11. Flow cytomeric measurement of DNA and incorporated nucleoside analogs

    DOEpatents

    Dolbeare, Frank A.; Gray, Joe W.

    1989-01-01

    A method is provided for simultaneously measuring total cellular DNA and incorporated nucleoside analog. The method entails altering the cellular DNA of cells grown in the presence of a nucleoside analog so that single stranded and double stranded portions are present. Separate stains are used against the two portions. An immunochemical stain is used against the single stranded portion to provide a measure of incorporated nucleoside analog, and a double strand DNA-specific stain is used against the double stranded portion to simultaneously provide a measure of total cellular DNA. The method permits rapid flow cytometric analysis of cell populations, rapid identification of cycling and noncycling subpopulations, and determination of the efficacy of S phase cytotoxic anticancer agents.

  12. Comparison of analog and digital pulse-shape-discrimination systems

    NASA Astrophysics Data System (ADS)

    Sosa, C. S.; Flaska, M.; Pozzi, S. A.

    2016-08-01

    Pulse shape discrimination (PSD) performance of two optimized PSD systems (one digital and one analog) is compared in this work. One system uses digital charge integration, while the other system uses analog zero crossing. Measurements were conducted with each PSD system using the CAEN V1720 (250 MHz) data acquisition system. An organic-liquid scintillator, coupled to a photo-multiplier tube, was used to detect neutrons and gamma rays from a Cf-252 spontaneous-fission source. The PSD performance of both systems was optimized and quantified using a traditional figure-of-merit (FOM) approach. FOM's were found for three, 300 keVee light-output bins, spanning from 100 to 1000 keVee, and one larger bin from 100 to 1800 keVee. Digital PSD outperformed analog PSD in the lowest light-output bin by approximately 50%, and by 11% for the highest light-output bin.

  13. Ethnographic analogy, the comparative method, and archaeological special pleading.

    PubMed

    Currie, Adrian

    2016-02-01

    Ethnographic analogy, the use of comparative data from anthropology to inform reconstructions of past human societies, has a troubled history. Archaeologists often express concern about, or outright reject, the practice--and sometimes do so in problematically general terms. This is odd, as (or so I argue) the use of comparative data in archaeology is the same pattern of reasoning as the 'comparative method' in biology, which is a well-developed and robust set of inferences which play a central role in discovering the biological past. In pointing out this continuity, I argue that there is no 'special pleading' on the part of archaeologists in this regard: biologists must overcome analogous epistemic difficulties in their use of comparative data. I then go on to emphasize the local, empirically tractable ways in which particular ethnographic analogies may be licensed.

  14. Discovery of a Jupiter/Saturn Analog with Gravitational Microlensing

    SciTech Connect

    Gaudi, B; Bennett, D; Udalski, A; Gould, A; Christie, G; Maoz, D; Dong, S; McCormick, J; Szymanski, M; Tristram, P; Nikolaev, S; Paczynski, B; Kubiak, M; Pietrzynski, G; Soszynski, I; Szewczyk, O; Ulaczyk, K; Wyrzykowski, L; DePoy, D; Han, C; Kaspi, S; Lee, C; Mallia, F; Natusch, T; Pogge, R; Park, B; Abe, F; Bond, I; Botzler, C; Fukui, A; Hearnshaw, J; Itow, Y; Kamiya, K; Korpela, A; Kilmartin, P; Lin, W; Masuda, K; Matsubara, Y; Motomura, M; Muraki, Y; Nakamura, S; Okumura, T; Ohnishi, K; Rattenbury, N; Sako, T; Saito, T; Sato, S; Skuljan, L; Sullivan, D; Sumi, T; Sweatman, W; Yock, P; Albrow, M; Beaulieu, J; Burgdorf, M; Cook, K; Coutures, C; Dominik, M; Dieters, S; Fouque, P; Greenhill, J; Horne, K; Steele, I; Tsapras, Y; Chaboyer, B; Crocker, A; Frank, S; Macintosh, B

    2007-11-08

    Searches for extrasolar planets have uncovered an astonishing diversity of planetary systems, yet the frequency of solar system analogs remains unknown. The gravitational microlensing planet search method is potentially sensitive to multiple-planet systems containing analogs of all the solar system planets except Mercury. We report the first detection of a multiple-planet system with microlensing. We identify two planets with masses of {approx} 0.71 and {approx} 0.27 times the mass of Jupiter and orbital separations of {approx} 2.3 and {approx} 4.6 astronomical units orbiting a primary of mass {approx} 0.50 solar masses. This system resembles a scaled version of our solar system in that the mass ratio, separation ratio, and equilibrium temperatures of the planets are similar to those of Jupiter and Saturn. These planets could not have been detected with other techniques; their discovery from only 6 confirmed microlensing planet detections suggests that solar system analogs may be common.

  15. The synthesis of spermine analogs of the shark aminosterol squalamine.

    PubMed

    Shu, Youheng; Jones, Stephen R; Kinney, William A; Selinsky, Barry S

    2002-03-01

    Aminosterols isolated from the dogfish shark Squalus acanthias are promising therapeutic agents in the treatment of infection and cancer. One of these, MSI-1436, has been shown to possess antimicrobial activity slightly better than squalamine. In this study, a series of analogs of MSI-1436 have been synthesized from stigmasterol. The 7 alpha-hydroxy substituent of MSI-1436 was either omitted or the stereochemistry modified to the 7 beta position. Also, analogs of MSI-1436 with 24-sulfate, 24-amino, and 24-hydroxy substituents were synthesized in order to assess the importance of the side chain functional group on antimicrobial activity. All of the analogs possess significant antimicrobial activity, suggesting that substitution at C7 and C24 of the aminosterols plays a minor role in their antimicrobial potency. PMID:11856553

  16. The Efficacy of Interactive Analogical Models in the Instruction of Bond Energy Curves in Undergraduate Chemistry

    ERIC Educational Resources Information Center

    Shahani, Vijay M.; Jenkinson, Jodie

    2016-01-01

    We explored analogies used for introducing students to the concept of potential energy wells. Two analogy systems were developed, a spring system and a novel system consisting of electrostatic spheres. These two, distinct analogies were housed within an interactive tool that allowed students to manipulate the analogous systems and witness changes…

  17. Analogical Reasoning in the Engineering Design Process and Technology Education Applications

    ERIC Educational Resources Information Center

    Daugherty, Jenny; Mentzer, Nathan

    2008-01-01

    This synthesis paper discusses the research exploring analogical reasoning, the role of analogies in the engineering design process, and educational applications for analogical reasoning. Researchers have discovered that analogical reasoning is often a fundamental cognitive tool in design problem solving. Regarding the possible role of analogical…

  18. System and method for linearly amplifying optical analog signals by backward Raman scattering

    DOEpatents

    Lin, Cheng-Heui

    1988-07-05

    A system for linearly amplifying an optical analog signal by backward stimulated Raman scattering comprises a laser source for generating a pump pulse; and an optic fiber having two opposed apertures, a first aperture for receiving the pump pulse and a second aperture for receiving the optical analog signal, wherein the optical analog signal is linearly amplified to an amplified optical analog signal.

  19. Effects of Multimedia and Schema Induced Analogical Reasoning on Science Learning

    ERIC Educational Resources Information Center

    Zheng, R. Z.; Yang, W.; Garcia, D.; McCadden, E. P.

    2008-01-01

    The present study investigates the effects of multimedia and schema induced analogical reasoning on science learning. It involves 89 fourth grade elementary students in the north-east of the United States. Participants are randomly assigned into four conditions: (a) multimedia with analogy; (b) multimedia without analogy; (c) analogy without…

  20. A Study on Analogies Used in New Ninth Grade Biology Textbook

    ERIC Educational Resources Information Center

    Dikmenli, Musa

    2015-01-01

    Analogies have many advantages for students such as concretizing abstract concepts and enabling motivation. Analogies are frequently used in textbooks. Research shows that the analogies in textbooks are not used based on certain directives and sometimes lead to misconceptions for students. Therefore, analysing the analogies in textbooks on several…

  1. Using Analogies in Teaching Physics: A Study on Latvian Teachers' Views and Experience

    ERIC Educational Resources Information Center

    Jonane, Lolita

    2015-01-01

    The role of analogies as tools for teaching difficult science concepts has been widely discussed in science education. The application of analogies in the context of sustainable education involves richer potential. The purposeful use of appropriate analogies can facilitate analogical thinking and transfer skills, as well as develop abilities which…

  2. The Discourse on Printed and Electronic Books: Analogies, Oppositions, and Perspectives

    ERIC Educational Resources Information Center

    Velagic, Zoran

    2014-01-01

    Introduction: The point of departure for this paper is the twofold analogy (analogy of content, analogy of medium) between printed and electronic books, the aim being to draw attention to the usual perception of their capacities and relationships, to provide a rather detailed analysis of the outcome and sustainability of such analogies and…

  3. The Teaching-with-Analogies Model: Build Conceptual Bridges with Mental Models

    ERIC Educational Resources Information Center

    Glynn, Shawn

    2007-01-01

    Teachers often use analogies and are unaware of it--they are using them automatically. Whenever they begin an explanation with "It's just like...," "It's similar to...," or "Think of it this way...," they are using an analogy to explain a concept to their students. An "analogy" is a similarity between concepts. Analogies can help students build…

  4. NASA's Analog Missions: Driving Exploration Through Innovative Testing

    NASA Technical Reports Server (NTRS)

    Reagan, Marcum L.; Janoiko, Barbara A.; Parker, Michele L.; Johnson, James E.; Chappell, Steven P.; Abercromby, Andrew F.

    2012-01-01

    Human exploration beyond low-Earth orbit (LEO) will require a unique collection of advanced, innovative technologies and the precise execution of complex and challenging operational concepts. One tool we in the Analog Missions Project at the National Aeronautics and Space Administration (NASA) utilize to validate exploration system architecture concepts and conduct technology demonstrations, while gaining a deeper understanding of system-wide technical and operational challenges, is our analog missions. Analog missions are multi-disciplinary activities that test multiple features of future spaceflight missions in an integrated fashion to gain a deeper understanding of system-level interactions and integrated operations. These missions frequently occur in remote and extreme environments that are representative in one or more ways to that of future spaceflight destinations. They allow us to test robotics, vehicle prototypes, habitats, communications systems, in-situ resource utilization, and human performance as it relates to these technologies. And they allow us to validate architectural concepts, conduct technology demonstrations, and gain a deeper understanding of system-wide technical and operational challenges needed to support crewed missions beyond LEO. As NASA develops a capability driven architecture for transporting crew to a variety of space environments, including the moon, near-Earth asteroids (NEA), Mars, and other destinations, it will use its analog missions to gather requirements and develop the technologies that are necessary to ensure successful human exploration beyond LEO. Currently, there are four analog mission platforms: Research and Technology Studies (RATS), NASA s Extreme Environment Mission Operations (NEEMO), In-Situ Resource Utilization (ISRU), and International Space Station (ISS) Test bed for Analog Research (ISTAR).

  5. Extensional flow of blood analog solutions in microfluidic devices

    PubMed Central

    Sousa, P. C.; Pinho, F. T.; Oliveira, M. S. N.; Alves, M. A.

    2011-01-01

    In this study, we show the importance of extensional rheology, in addition to the shear rheology, in the choice of blood analog solutions intended to be used in vitro for mimicking the microcirculatory system. For this purpose, we compare the flow of a Newtonian fluid and two well-established viscoelastic blood analog polymer solutions through microfluidic channels containing both hyperbolic and abrupt contractions∕expansions. The hyperbolic shape was selected in order to impose a nearly constant strain rate at the centerline of the microchannels and achieve a quasihomogeneous and strong extensional flow often found in features of the human microcirculatory system such as stenoses. The two blood analog fluids used are aqueous solutions of a polyacrylamide (125 ppm w∕w) and of a xanthan gum (500 ppm w∕w), which were characterized rheologically in steady-shear flow using a rotational rheometer and in extension using a capillary breakup extensional rheometer (CaBER). Both blood analogs exhibit a shear-thinning behavior similar to that of whole human blood, but their relaxation times, obtained from CaBER experiments, are substantially different (by one order of magnitude). Visualizations of the flow patterns using streak photography, measurements of the velocity field using microparticle image velocimetry, and pressure-drop measurements were carried out experimentally for a wide range of flow rates. The experimental results were also compared with the numerical simulations of the flow of a Newtonian fluid and a generalized Newtonian fluid with shear-thinning behavior. Our results show that the flow patterns of the two blood analog solutions are considerably different, despite their similar shear rheology. Furthermore, we demonstrate that the elastic properties of the fluid have a major impact on the flow characteristics, with the polyacrylamide solution exhibiting a much stronger elastic character. As such, these properties must be taken into account in the

  6. VUV spectroscopy of carbon dust analogs: contribution to interstellar extinction

    NASA Astrophysics Data System (ADS)

    Gavilan, L.; Alata, I.; Le, K. C.; Pino, T.; Giuliani, A.; Dartois, E.

    2016-02-01

    Context. A full spectral characterization of carbonaceous dust analogs is necessary to understand their potential as carriers of observed astronomical spectral signatures such as the ubiquitous UV bump at 217.5 nm and the far-ultraviolet (FUV) rise common to interstellar extinction curves. Aims: Our goal is to study the spectral properties of carbonaceous dust analogs from the FUV to the mid-infrared (MIR) domain. We seek in particular to understand the spectra of these materials in the FUV range, for which laboratory studies are scarce. Methods: We produced analogs to carbonaceous interstellar dust encountered in various phases of the interstellar medium: amorphous hydrogenated carbons (a-C:H), for carbonaceous dust observed in the diffuse interstellar medium, and soot particles, for the polyaromatic component. Analogs to a-C:H dust were produced using a radio-frequency plasma reactor at low pressures, and soot nanoparticles films were produced in an ethylene (C2H4) flame. We measured transmission spectra of these thin films (thickness <100 nm) in the far-ultraviolet (190-250 nm) and in the vacuum-ultraviolet (VUV; 50-190 nm) regions using the APEX chamber at the DISCO beam line of the SOLEIL synchrotron radiation facility. These were also characterized through infrared microscopy at the SMIS beam line. Results: We successfully measured the transmission spectra of these analogs from λ = 1 μm to 50 nm. From these, we extracted the laboratory optical constants via Kramers-Kronig inversion. We used these constants for comparison to existing interstellar extinction curves. Conclusions: We extend the spectral measurements of these types of carbonaceous analogs into the VUV and link the spectral features in this range to the 3.4 μm band. We suggest that these two materials might contribute to different classes of interstellar extinction curves.

  7. The Expanding Role of Somatostatin Analogs in the Management of Neuroendocrine Tumors

    PubMed Central

    2012-01-01

    ABSTRACT BACKGROUND: Neuroendocrine tumors (NETs) are neoplasms arising most often in the GI tract, pancreas, or lung. Diagnosis of NETs is often delayed until the disease is advanced, because of the variable and nonspecific nature of the initial symptoms. Surgical resection for cure is therefore not an option for most patients. METHODS: Somatostatin analogues represent the cornerstone of therapy for patients with NETs. This article reviews the important role that somatostatin analogues continue to play in the treatment of patients with NETs. RESULTS: Octreotide was the first somatostatin analogue to be developed; more than 30 years of data have accumulated demonstrating its efficacy and safety. Lanreotide is another somatostatin analogue in clinical use, and pasireotide is a promising somatostatin analogue in development. Newer long-acting depot formulations are now available offering once-monthly administration. Although octreotide was initially developed for symptom control, recent results indicate that it also has an antiproliferative effect, significantly increasing time to progression in patients with midgut NETs. Combinations of octreotide with other targeted therapies may further improve patient outcomes. Findings in recent studies of the combination of octreotide and the mTOR inhibitor everolimus are encouraging. The combinations of octreotide with other agents (eg, interferon-α, bevacizumab, cetuximab, AMG-706, and sunitinib) are being investigated. CONCLUSIONS: Somatostatin analogues have been used to treat the symptoms of NETs for decades and also have an antineoplastic effect, markedly prolonging progression-free survival. Somatostatin analogues are likely to remain the cornerstone of treatment for most patients with advanced NETs. Promising new combination therapies are undergoing clinical investigation. PMID:23112884

  8. Active geothermal systems as natural analogs of HLW repositories

    SciTech Connect

    Elders, W.A.; Williams, A.E.; Cohen, L.H.

    1988-01-01

    Geologic analogs of long-lived processes in high-level waste (HLW) repositories have been much studied in recent years. However, most of these occurrences either involve natural processes going on today at 25{degree}C, or, if they are concerned with behavior at temperatures similar to the peak temperatures anticipated near HLW canisters, have long since ended. This paper points out the usefulness of studying modern geothermal systems as natural analogs, and to illustrate the concept with a dramatic example, the Salton Sea geothermal system (SSGS).

  9. Analog-digital models of stream-aquifer systems

    USGS Publications Warehouse

    Moulder, E.A.; Jenkins, C.T.

    1969-01-01

    The best features of analog and digital computers were combined to make a management model of a stream-aquifer system. The analog model provides a means for synthesizing, verifying, and summarizing aquifer properties; the digital model permits rapid calculation of the effects of water management practices. Given specific management alternatives, a digital program can be written that will optimize operation plans of stream-aquifer systems. The techniques are demonstrated by application to a study of the Arkansas River valley in southeastern Colorado.

  10. Cell sorting is analogous to phase ordering in fluids

    NASA Astrophysics Data System (ADS)

    Beysens, D. A.; Forgacs, G.; Glazier, J. A.

    2000-08-01

    Morphogenetic processes, like sorting or spreading of tissues, characterize early embryonic development. An analogy between viscoelastic fluids and certain properties of embryonic tissues helps interpret these phenomena. The values of tissue-specific surface tensions are consistent with the equilibrium configurations that the Differential Adhesion Hypothesis predicts such tissues reach after sorting and spreading. Here we extend the fluid analogy to cellular kinetics. The same formalism applies to recent experiments on the kinetics of phase ordering in two-phase fluids. Our results provide biologically relevant information on the strength of binding between cell adhesion molecules under near-physiological conditions.

  11. Resolver to 360.degree. linear analog converter and method

    NASA Technical Reports Server (NTRS)

    Alhorn, Dean C. (Inventor); Howard, David E. (Inventor); Smith, Dennis A. (Inventor)

    2000-01-01

    The converter produces a linear analog signal that is linearly proportional to a shaft angle of a resolver over 360.degree.. An excitation cosine signal supplied to the resolver and a response cosine signal received from the output windings of the resolver are converted to logic level signals. Digital logic is performed on the logic level signals in a programmable digital logic device to produce a logic level pulse-width modulated signal. The logic level pulse-width modulated signal is used to control a switch to switch between two reference voltage levels to produce a pulse-width modulated signal, which is filtered and buffered to produce the linear analog signal.

  12. Measurement of control system response using an analog operational circuit

    NASA Technical Reports Server (NTRS)

    Lalli, V. R.

    1978-01-01

    Ten basic steps are established for an analog method that measures control system response parameters. An example shows how these steps were used on a speed control portion of an auxiliary power unit. The equations and calculations necessary to describe this subsystem are given. The mechanization schematic and simulation diagram for obtaining the measured response parameters of the control system using an analog circuit are explained. Methods for investigating the various effects of the control parameters are described. It is concluded that the optimum system should be underdamped enough to be slightly oscillatory during transients.

  13. On automatic synthesis of analog/digital circuits

    SciTech Connect

    Beiu, V.

    1998-12-31

    The paper builds on a recent explicit numerical algorithm for Kolmogorov`s superpositions, and will show that in order to synthesize minimum size (i.e., size-optimal) circuits for implementing any Boolean function, the nonlinear activation function of the gates has to be the identity function. Because classical and--or implementations, as well as threshold gate implementations require exponential size, it follows that size-optimal solutions for implementing arbitrary Boolean functions can be obtained using analog (or mixed analog/digital) circuits. Conclusions and several comments are ending the paper.

  14. Teamwork in high-risk environments analogous to space

    NASA Technical Reports Server (NTRS)

    Kanki, Barbara G.

    1990-01-01

    Mountaineering expeditions combine a number of factors which make them potentially good analogs to the planetary exploration facet of long-duration space missions. A study of mountain climbing teams was conducted in order to evaluate the usefulness of the environment as a space analog and to specifically identify the factors and issues surrounding teamwork and 'successful' team performance in two mountaineering environments. This paper focuses on social/organizational factors, including team size and structure, leadership styles and authority structure which were found in the sample of 22 climb teams (122 individuals). The second major issue discussed is the construction of a valid performance measure in this high-risk environment.

  15. Dual chain synthetic heparin-binding growth factor analogs

    DOEpatents

    Zamora, Paul O.; Pena, Louis A.; Lin, Xinhua

    2009-10-06

    The invention provides synthetic heparin-binding growth factor analogs having two peptide chains each branched from a branch moiety, such as trifunctional amino acid residues, the branch moieties separated by a first linker of from 3 to about 20 backbone atoms, which peptide chains bind a heparin-binding growth factor receptor and are covalently bound to a non-signaling peptide that includes a heparin-binding domain, preferably by a second linker, which may be a hydrophobic second linker. The synthetic heparin-binding growth factor analogs are useful as pharmaceutical agents, soluble biologics or as surface coatings for medical devices.

  16. Dual chain synthetic heparin-binding growth factor analogs

    DOEpatents

    Zamora, Paul O.; Pena, Louis A.; Lin, Xinhua

    2012-04-24

    The invention provides synthetic heparin-binding growth factor analogs having two peptide chains each branched from a branch moiety, such as trifunctional amino acid residues, the branch moieties separated by a first linker of from 3 to about 20 backbone atoms, which peptide chains bind a heparin-binding growth factor receptor and are covalently bound to a non-signaling peptide that includes a heparin-binding domain, preferably by a second linker, which may be a hydrophobic second linker. The synthetic heparin-binding growth factor analogs are useful as pharmaceutical agents, soluble biologics or as surface coatings for medical devices.

  17. Automatic Synthesis of CMOS Algorithmic Analog To-Digital Converter.

    NASA Astrophysics Data System (ADS)

    Jusuf, Gani

    The steady decrease in technological feature size is allowing increasing levels of integration in analog/digital interface functions. These functions consist of analog as well as digital circuits. While the turn around time for an all digital IC chip is very short due to the maturity of digital IC computer-aided design (CAD) tools over the last ten years, most analog circuits have to be designed manually due to the lack of analog IC CAD tools. As a result, analog circuit design becomes the bottleneck in the design of mixed signal processing chips. One common analog function in a mixed signal processing chip is an analog-to-digital conversion (ADC) function. This function recurs frequently but with varying performance requirements. The objective of this research is to study the design methodology of a compilation program capable of synthesizing ADC's with a broad range of sampling rates and resolution, and silicon area and performance comparable with the manual approach. The automatic compilation of the ADC function is a difficult problem mainly because ADC techniques span such a wide spectrum of performance, with radically different implementations being optimum for different ranges of conversion range, resolution, and power dissipation. We will show that a proper choice of the ADC architectures and the incorporation of many analog circuit design techniques will simplify the synthesis procedure tremendously. Moreover, in order to speed up the device sizing, hierarchical optimization procedure and behavioral simulation are implemented into the ADC module generation steps. As a result of this study, a new improved algorithmic ADC without the need of high precision comparators has been developed. This type of ADC lends itself to automatic generation due to its modularity, simplicity, small area consumption, moderate speed, low power dissipation, and single parameter trim capability that can be added at high resolution. Furthermore, a performance-driven CMOS ADC module

  18. An inexpensive 15 MHz fiber optic analog data link

    NASA Astrophysics Data System (ADS)

    Lagerstroem, E.; Kindberg, G.; Haegerstroem, G.; Drake, J. R.

    1982-03-01

    Circuit diagrams for the transmitter and receiver for an analog data link are presented. Analog signals are transmitted over distances of several meters via a fiber optic cable. System bandwidth is 10 to 15 MHz with a gain of unity for amplitudes of + or - 0.5 V. Transmission is switched to dc if moderate drift is acceptable. The signal to noise ratio is 46 dB which can be improved if a 5 MHz filter is used with transient recorders with a 20 MHz digitizing rate. A surge arrester protects against very fast high amplitude voltage spikes.

  19. Foucault's Pendulum, Analog for an Electron Spin State

    NASA Astrophysics Data System (ADS)

    Linck, Rebecca

    2012-11-01

    The classical Lagrangian that describes the coupled oscillations of Foucault's pendulum presents an interesting analog to an electron's spin state in an external magnetic field. With a simple modification, this classical Lagrangian yields equations of motion that directly map onto the Schrodinger-Pauli Equation. This analog goes well beyond the geometric phase, reproducing a broad range of behavior from Zeeman-like frequency splitting to precession of the spin state. By demonstrating that unmeasured spin states can be fully described in classical terms, this research opens the door to using the tools of classical physics to examine an inherently quantum phenomenon.

  20. Infrared spectra of lunar soil analogs. [spectral reflectance of minerals

    NASA Technical Reports Server (NTRS)

    Aronson, J. R.

    1977-01-01

    The infrared spectra of analogs of lunar soils were investigated to further the development of methodology for interpretation of remotely measured infrared spectra of the lunar surface. The optical constants of dunite, bytownite, augite, ilmenite, and a mare glass analog were obtained. The infrared emittance spectra of powdered minerals were measured and compared with spectra calculated by the reflectance theory using a catalog of optical constants. The results indicate that the predictions of the theory closely simulate the experimental measurements if the optical constants are properly derived.

  1. Developing a 300C Analog Tool for EGS

    SciTech Connect

    Normann, Randy

    2015-03-23

    This paper covers the development of a 300°C geothermal well monitoring tool for supporting future EGS (enhanced geothermal systems) power production. This is the first of 3 tools planed. This is an analog tool designed for monitoring well pressure and temperature. There is discussion on 3 different circuit topologies and the development of the supporting surface electronics and software. There is information on testing electronic circuits and component. One of the major components is the cable used to connect the analog tool to the surface.

  2. The use of Antarctic analogs for the Space Exploration Initiative

    NASA Technical Reports Server (NTRS)

    Roberts, Barney; Lynch, John T.

    1991-01-01

    Potential approaches to the use of the Antarctic as an analog to the lunar and Mars planetary surface segments of the SEI are reviewed. It is concluded that a well-planned and sustained program of ground-based research and testing in environments analogous to the moon and Mars is a rational method for reducing the risks associated with human space missions. Antarctica may provide an ideal setting for testing critical technologies (habitat design, life support, and advanced scientific instrumentation), studying human factors and physiology, and conducting basic scientific research similar to and directly relevant to that planned for the SEI.

  3. Real time image processing with an analog vision chip system.

    PubMed

    Kameda, S; Honda, A; Yagi, T

    1999-10-01

    A linear analog network model is proposed to characterize the function of the outer retinal circuit in terms of the standard regularization theory. Inspired by the function and the architecture of the model, a vision chip has been designed using analog CMOS Very Large Scale Integrated circuit technology. In the chip, sample/hold amplifier circuits are incorporated to compensate for statistic transistor mismatches. Accordingly, extremely low noise outputs were obtained from the chip. Using the chip and a zero-crossing detector, edges of given images were effectively extracted in indoor illumination.

  4. Fast-response frequency-to-analog converter

    NASA Technical Reports Server (NTRS)

    Hagihara, F. S.

    1967-01-01

    Frequency-to-analog converter has a fast response time and a low ripple. The circuit uses a frequency-to-pulse converter which provides two pulse trains, both at the same frequency as that of the input signal, but with a 10 microsecond difference between the trains.

  5. Prelinguistic Relational Concepts: Investigating Analogical Processing in Infants

    ERIC Educational Resources Information Center

    Ferry, Alissa L.; Hespos, Susan J.; Gentner, Dedre

    2015-01-01

    This research asks whether analogical processing ability is present in human infants, using the simplest and most basic relation--the "same-different" relation. Experiment 1 (N = 26) tested whether 7- and 9-month-olds spontaneously detect and generalize these relations from a single example, as previous research has suggested. The…

  6. 47 CFR 74.705 - TV broadcast analog station protection.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Translator, and TV Booster Stations § 74.705 TV broadcast analog station protection. (a) The TV broadcast... § 73.699. (b)(1) An application to construct a new low power TV or TV translator station or change the...) of part 73 of this chapter.) (3) A UHF low power TV or TV translator construction permit...

  7. Linking Gestures: Cross-Cultural Variation during Instructional Analogies

    ERIC Educational Resources Information Center

    Richland, Lindsey Engle

    2015-01-01

    Deictic linking gestures, hand and arm motions that physically embody links being communicated between two or more objects in the shared communicative environment, are explored in a cross-cultural sample of mathematics instruction. Linking gestures are specifically examined here when they occur in the context of communicative analogies designed to…

  8. Toward "Constructing" the Concept of Statistical Power: An Optical Analogy.

    ERIC Educational Resources Information Center

    Rogers, Bruce G.

    This paper presents a visual analogy that may be used by instructors to teach the concept of statistical power in statistical courses. Statistical power is mathematically defined as the probability of rejecting a null hypothesis when that null is false, or, equivalently, the probability of detecting a relationship when it exists. The analogy…

  9. Analogy and Intersubjectivity: Political Oratory, Scholarly Argument and Scientific Reports.

    ERIC Educational Resources Information Center

    Gross, Alan G.

    1983-01-01

    Focuses on the different ways political oratory, scholarly argument, and scientific reports use analogy. Specifically, analyzes intersubjective agreement in Franklin D. Roosevelt's First Inaugural address, the scholarly argument between Sir Karl Popper and Thomas S. Kuhn, and the scientific reports of various mathematicians and scientists. (PD)

  10. Selection and Implementation of Strategies in Reasoning by Analogy.

    ERIC Educational Resources Information Center

    Sternberg, Robert J.; Ketron, Jerry L.

    1982-01-01

    Considering content, task-execution and subject variables in metacognitive and cognitive performance, analogies with integral or separable attributes were solved by selected undergraduate students with training in one of three task strategies or no strategy training. Training success, subject awareness of variables, score correlations, and…

  11. Two-Photon-Induced Fluorescence of Isomorphic Nucleobase Analogs

    PubMed Central

    Lane, Richard S. K.; Jones, Rosemary; Sinkeldam, Renatus W.

    2014-01-01

    Five isomorphic fluorescent uridine mimics have been subjected to two-photon (2P) excitation analysis to investigate their potential applicability as non-perturbing probes for the single-molecule detection of nucleic acids. We find that small structural differences can cause major changes in the two-photon excitation probability, with the 2P cross sections varying by over one order of magnitude. Two of the probes, both furan-modified uridine analogs, have the highest 2P cross sections (3.8 GM and 7.6 GM) reported for nucleobase analogs, using a conventional Ti:sapphire laser for excitation at 690 nm; they also have the lowest emission quantum yields. In contrast, the analogs with the highest reported quantum yields have the lowest 2P cross sections. The structure-photophysical property relationship presented here is a first step towards the rational design of emissive nucleobase analogs with controlled 2P characteristics. The results demonstrate the potential for major improvements through judicious structural modifications. PMID:24604669

  12. Architectures for optoelectronic analogs of self-organizing neural networks.

    PubMed

    Farhat, N H

    1987-06-01

    Architectures for partitioning optoelectronic analogs of neural nets into input-output and internal groups to form a multilayered net capable of self-organization, self-programming, and learning are described. The architectures and implementation ideas given describe a class of optoelectronic neural net modules that, when interfaced to a conventional computer controller, can impart to it artificial intelligence attributes.

  13. Analysis and survival of amino acids in Martian regolith analogs

    NASA Astrophysics Data System (ADS)

    Garry, James R. C.; Loes Ten Kate, Inge; Martins, Zita; Nørnberg, Per; Ehrenfreund, Pascale

    2006-03-01

    We have investigated the native amino acid composition of two analogs of Martian soil, JSC Mars-1 and Salten Skov. A Mars simulation chamber has been built and used to expose samples of these analogs to temperature and lighting conditions similar to those found at low latitudes on the Martian surface. The effects of the simulated conditions have been examined using high-performance liquid chromatography (HPLC). Exposure to energetic ultraviolet (UV) light in vacuum appears to cause a modest increase in the concentration of certain amino acids within the materials, which is interpreted as resulting from the degradation of microorganisms. The influence of low temperatures shows that the accretion of condensed water on the soils leads to the destruction of amino acids, supporting the idea that reactive chemical processes involving H2O are at work within the Martian soil. We discuss the influence of UV radiation, low temperatures, and gaseous CO2 on the intrinsic amino acid composition of Martian soil analogs and describe, with the help of a simple model, how these studies fit within the framework of life detection on Mars and the practical tasks of choosing and using Martian regolith analogs in planetary research.

  14. Spontaneous Analog Number Representations in 3-Year-Old Children

    ERIC Educational Resources Information Center

    Cantlon, Jessica F.; Safford, Kelley E.; Brannon, Elizabeth M.

    2010-01-01

    When enumerating small sets of elements nonverbally, human infants often show a set-size limitation whereby they are unable to represent sets larger than three elements. This finding has been interpreted as evidence that infants spontaneously represent small numbers with an object-file system instead of an analog magnitude system (Feigenson,…

  15. Analog neural network-based helicopter gearbox health monitoring system.

    PubMed

    Monsen, P T; Dzwonczyk, M; Manolakos, E S

    1995-12-01

    The development of a reliable helicopter gearbox health monitoring system (HMS) has been the subject of considerable research over the past 15 years. The deployment of such a system could lead to a significant saving in lives and vehicles as well as dramatically reduce the cost of helicopter maintenance. Recent research results indicate that a neural network-based system could provide a viable solution to the problem. This paper presents two neural network-based realizations of an HMS system. A hybrid (digital/analog) neural system is proposed as an extremely accurate off-line monitoring tool used to reduce helicopter gearbox maintenance costs. In addition, an all analog neural network is proposed as a real-time helicopter gearbox fault monitor that can exploit the ability of an analog neural network to directly compute the discrete Fourier transform (DFT) as a sum of weighted samples. Hardware performance results are obtained using the Integrated Neural Computing Architecture (INCA/1) analog neural network platform that was designed and developed at The Charles Stark Draper Laboratory. The results indicate that it is possible to achieve a 100% fault detection rate with 0% false alarm rate by performing a DFT directly on the first layer of INCA/1 followed by a small-size two-layer feed-forward neural network and a simple post-processing majority voting stage.

  16. Cerebral correlates of analogical processing and their modulation by training.

    PubMed

    Wartenburger, Isabell; Heekeren, Hauke R; Preusse, Franziska; Kramer, Jürg; van der Meer, Elke

    2009-10-15

    There is increasing interest in understanding the neural systems that mediate analogical thinking, which is essential for learning and fluid intelligence. The aim of the present study was to shed light on the cerebral correlates of geometric analogical processing and on training-induced changes at the behavioral and brain level. In healthy participants a bilateral fronto-parietal network was engaged in processing geometric analogies and showed greater blood oxygenation dependent (BOLD) signals as resource demands increased. This network, as well as fusiform and subcortical brain regions, additionally showed training-induced decreases in the BOLD signal over time. The general finding that brain regions were modulated by the amount of resources demanded by the task, and/or by the reduction of allocated resources due to short term training, reflects increased efficiency--in terms of more focal and more specialized brain activation--to more economically process the geometric analogies. Our data indicate a rapid adaptation of the cognitive system which is efficiently modulated by short term training based on a positive correlation of resource demands and brain activation.

  17. Emergent Verbal Behavior and Analogy: Skinnerian and Linguistic Approaches

    ERIC Educational Resources Information Center

    Matos, Maria Amelia; Passos, Maria de Lourdes

    2010-01-01

    The production of verbal operants not previously taught is an important aspect of language productivity. For Skinner, new mands, tacts, and autoclitics result from the recombination of verbal operants. The relation between these mands, tacts, and autoclitics is what linguists call "analogy," a grammatical pattern that serves as a foundation on…

  18. Precision-analog fiber-optic transmission system

    SciTech Connect

    Stover, G.

    1981-06-01

    This article describes the design, experimental development, and construction of a DC-coupled precision analog fiber optic link. Topics to be covered include overall electrical and mechanical system parameters, basic circuit organization, modulation format, optical system design, optical receiver circuit analysis, and the experimental verification of the major design parameters.

  19. Rapid Learning in a Children's Museum via Analogical Comparison

    ERIC Educational Resources Information Center

    Gentner, Dedre; Levine, Susan C.; Ping, Raedy; Isaia, Ashley; Dhillon, Sonica; Bradley, Claire; Honke, Garrett

    2016-01-01

    We tested whether analogical training could help children learn a key principle of elementary engineering--namely, the use of a diagonal brace to stabilize a structure. The context for this learning was a construction activity at the Chicago Children's Museum, in which children and their families build a model skyscraper together. The results…

  20. Mimetic analogs of three insect neuropeptide classes for pest management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Neuropeptides are potent regulators of critical life processes in insects, but are subjected to rapid degradation by peptidases in the hemolymph (blood), tissues and gut. This limitation can be overcome via replacement of peptidase susceptible portions of the insect neuropeptides to create analogs w...

  1. Mimetic analogs of pyrokinin neuropeptides for pest management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Neuropeptides are potent regulators of critical life processes in insects, but are subjected to rapid degradation by peptidases in the hemolymph (blood), tissues and gut. This limitation can be overcome via replacement of peptidase susceptible portions of the insect neuropeptides to create analogs ...

  2. RANKING RELATIONS USING ANALOGIES IN BIOLOGICAL AND INFORMATION NETWORKS1

    PubMed Central

    Silva, Ricardo; Heller, Katherine; Ghahramani, Zoubin; Airoldi, Edoardo M.

    2013-01-01

    Analogical reasoning depends fundamentally on the ability to learn and generalize about relations between objects. We develop an approach to relational learning which, given a set of pairs of objects S = {A(1) : B(1), A(2) : B(2), …, A(N) : B(N)}, measures how well other pairs A : B fit in with the set S. Our work addresses the following question: is the relation between objects A and B analogous to those relations found in S? Such questions are particularly relevant in information retrieval, where an investigator might want to search for analogous pairs of objects that match the query set of interest. There are many ways in which objects can be related, making the task of measuring analogies very challenging. Our approach combines a similarity measure on function spaces with Bayesian analysis to produce a ranking. It requires data containing features of the objects of interest and a link matrix specifying which relationships exist; no further attributes of such relationships are necessary. We illustrate the potential of our method on text analysis and information networks. An application on discovering functional interactions between pairs of proteins is discussed in detail, where we show that our approach can work in practice even if a small set of protein pairs is provided. PMID:24587838

  3. The Pulley Analogy Does Not Work for Every Siphon

    ERIC Educational Resources Information Center

    Planinsic, Gorazd; Slisko, Josip

    2010-01-01

    How do siphons work? Some see atmospheric pressure, explicitly or implicitly, as a crucial factor in siphon action. Others explain that a siphon works due to a difference of water weights in unequal arms. According to the latter view, siphon action is analogous to the action of a pulley or to the behaviour of a chain that is moving over a tube. In…

  4. Seeking Instructional Specificity: An Example from Analogical Instruction

    ERIC Educational Resources Information Center

    Kuo, Eric; Wieman, Carl E.

    2015-01-01

    Broad instructional methods like "interactive engagement" have been shown to be effective, but such general characterization provides little guidance on the details of how to structure instructional materials. In this study, we seek instructional specificity by comparing two ways of using an analogy to learn a target physical principle:…

  5. Emergent Verbal Behavior and Analogy: Skinnerian and Linguistic Approaches

    PubMed Central

    Matos, Maria Amelia; de Lourdes Passos, Maria

    2010-01-01

    The production of verbal operants not previously taught is an important aspect of language productivity. For Skinner, new mands, tacts, and autoclitics result from the recombination of verbal operants. The relation between these mands, tacts, and autoclitics is what linguists call analogy, a grammatical pattern that serves as a foundation on which a speaker might emit new linguistic forms. Analogy appears in linguistics as a regularity principle that characterizes language and has been related to how languages change and also to creativity. The approaches of neogrammarians like Hermann Paul, as well as those of Jespersen and Bloomfield, appear to have influenced Skinner's understanding of verbal creativity. Generalization and stimulus equivalence are behavioral processes related to the generative grammatical behavior described in the analogy model. Linguistic forms and grammatical patterns described in analogy are part of the contingencies of reinforcement that produce generalization and stimulus equivalence. The analysis of verbal behavior needs linguistic analyses of the constituents of linguistic forms and their combination patterns. PMID:22479127

  6. A synthetic kisspeptin analog that triggers ovulation and advances puberty

    PubMed Central

    Decourt, C.; Robert, V.; Anger, K.; Galibert, M.; Madinier, J.-B.; Liu, X.; Dardente, H.; Lomet, D.; Delmas, A. F.; Caraty, A.; Herbison, A. E.; Anderson, G. M; Aucagne, V.; Beltramo, M.

    2016-01-01

    The neuropeptide kisspeptin and its receptor, KiSS1R, govern the reproductive timeline of mammals by triggering puberty onset and promoting ovulation by stimulating gonadotrophin-releasing hormone (GnRH) secretion. To overcome the drawback of kisspeptin short half-life we designed kisspeptin analogs combining original modifications, triazole peptidomimetic and albumin binding motif, to reduce proteolytic degradation and to slow down renal clearance, respectively. These analogs showed improved in vitro potency and dramatically enhanced pharmacodynamics. When injected intramuscularly into ewes (15 nmol/ewe) primed with a progestogen, the best analog (compound 6, C6) induced synchronized ovulations in both breeding and non-breeding seasons. Ovulations were fertile as demonstrated by the delivery of lambs at term. C6 was also fully active in both female and male mice but was completely inactive in KiSS1R KO mice. Electrophysiological recordings of GnRH neurons from brain slices of GnRH-GFP mice indicated that C6 exerted a direct excitatory action on GnRH neurons. Finally, in prepubertal female mice daily injections (0.3 nmol/mouse) for five days significantly advanced puberty. C6 ability to trigger ovulation and advance puberty demonstrates that kisspeptin analogs may find application in the management of livestock reproduction and opens new possibilities for the treatment of reproductive disorders in humans. PMID:27245315

  7. Spectroscopy and reactivity of mineral analogs of the Martian soil

    NASA Technical Reports Server (NTRS)

    Banin, A.; Orenberg, J.; Roush, T.

    1991-01-01

    To answer the question of why life occurred on Earth but not on Mars requires a study of the geochemical and physical aspects of the Martian soil. Some of the best Mars analog mineral models of the soil have been prepared and justified according to known constraints of chemical composition, reflectance spectroscopy, and chemical reactivity. Detailed laboratory reflectance spectra in the ultraviolet, visible, and near infrared (.30 to 2.5 microns) and the infrared (2.5 to 25 microns) regions have been obtained for the pure candidate minerals and some analog mixtures and compared to Mars reflectance spectra. Modeling of the reflectance spectra from optical constraints determined for the analog minerals has begun and will be interpreted in terms of the effects of particle size variation, component mixing, and soil packing upon remotely sensed reflectance spectra. This has implications not only for Mars, but for other planets and planetoids. The ratio of Fe(II)/Fe(III) in the Martian soil analog materials on spectral reflectance in the visible range has begun, and the results will be evaluated according to conformity with the visible Mars reflectance spectrum. Some initial LR and GEX data have been collected for the mineral samples and their mixtures, which can be compared with the Viking data and interpreted in terms of the redox (Fe(II)/Fe(III) environment.

  8. Listening Comprehension Technology: Building the Bridge from Analog to Digital

    ERIC Educational Resources Information Center

    Jones, Linda C.

    2008-01-01

    Listening comprehension has had a long and ever-evolving history. Within the last 100 years, we have seen it progress from analog phonograph recordings, through the audiotape era, and into the digital realm. Questions arise as to how this evolution has proceeded, what pitfalls and accomplishments we have experienced, and where we might envision…

  9. Application of natural analog studies to exploration for ore deposits

    SciTech Connect

    Gustafson, D.L.

    1995-09-01

    Natural analogs are viewed as similarities in nature and are routinely utilized by exploration geologists in their search for economic mineral deposits. Ore deposit modeling is undertaken by geologists to direct their exploration activities toward favorable geologic environments and, therefore, successful programs. Two types of modeling are presented: (i) empirical model development based on the study of known ore deposit characteristics, and (ii) concept model development based on theoretical considerations and field observations that suggest a new deposit type, not known to exist in nature, may exist and justifies an exploration program. Key elements that are important in empirical model development are described, and examples of successful applications of these natural analogs to exploration are presented. A classical example of successful concept model development, the discovery of the McLaughlin gold mine in California, is presented. The utilization of natural analogs is an important facet of mineral exploration. Natural analogs guide explorationists in their search for new discoveries, increase the probability of success, and may decrease overall exploration expenditure.

  10. Natural analogs for far-field environment/hydrology

    SciTech Connect

    Hoxie, D.T.

    1995-09-01

    This paper discusses the applicability of natural-analog studies to characterize far-field conditions in the vicinity of geologic repository systems for the disposal of high-level radioactive wastes. Conditions in the far field are determined by the natural state and evolution of the repository geosphere and its environment.

  11. Anticancer activity of methyl-substituted oxaliplatin analogs.

    PubMed

    Jungwirth, Ute; Xanthos, Dimitris N; Gojo, Johannes; Bytzek, Anna K; Körner, Wilfried; Heffeter, Petra; Abramkin, Sergey A; Jakupec, Michael A; Hartinger, Christian G; Windberger, Ursula; Galanski, Markus; Keppler, Bernhard K; Berger, Walter

    2012-05-01

    Oxaliplatin is successfully used in systemic cancer therapy. However, resistance development and severe adverse effects are limiting factors for curative cancer treatment with oxaliplatin. The purpose of this study was to comparatively investigate in vitro and in vivo anticancer properties as well as the adverse effects of two methyl-substituted enantiomerically pure oxaliplatin analogs [[(1R,2R,4R)-4-methyl-1,2-cyclohexanediamine] oxalatoplatinum(II) (KP1537), and [(1R,2R,4S)-4-methyl-1,2-cyclohexanediamine]oxalatoplatinum(II) (KP1691)] and to evaluate the impact of stereoisomerism. Although the novel oxaliplatin analogs demonstrated in multiple aspects activities comparable with those of the parental compound, several key differences were discovered. The analogs were characterized by reduced vulnerability to resistance mechanisms such as p53 mutations, reduced dependence on immunogenic cell death induction, and distinctly attenuated adverse effects including weight loss and cold hyperalgesia. Stereoisomerism of the substituted methyl group had a complex and in some aspects even contradictory impact on drug accumulation and anticancer activity both in vitro and in vivo. To summarize, methyl-substituted oxaliplatin analogs harbor improved therapeutic characteristics including significantly reduced adverse effects. Hence, they might be promising metal-based anticancer drug candidates for further (pre)clinical evaluation.

  12. Difference in brain activations during appreciating paintings and photographic analogs

    PubMed Central

    Mizokami, Yoshinori; Terao, Takeshi; Hatano, Koji; Hoaki, Nobuhiko; Kohno, Kentaro; Araki, Yasuo; Kodama, Kensuke; Makino, Mayu; Izumi, Toshihiko; Shimomura, Tsuyoshi; Fujiki, Minoru; Kochiyama, Takanori

    2014-01-01

    Several studies have investigated neural correlates of aesthetic appreciation for paintings but to date the findings have been heterogeneous. This heterogeneity may be attributed to previous studies’ measurement of aesthetic appreciation of not only the beauty of paintings but also the beauty of motifs of the paintings. In order to better elucidate the beauty of paintings, it seems necessary to compare aesthetic appreciation of paintings and photographic analogs which included corresponding real images. We prepared for famous painters’ pictures and their photographic analogs which were set up to resemble each painting in order to investigate the hypothesis that there exist specific neural correlates associated with the aesthetic appreciation for paintings. Forty-four subjects participated in functional magnetic resonance study which required comparisons of aesthetic appreciation of paintings of still life and landscape versus photographic analogs including corresponding real images of still life and landscape. Bilateral cuneus and the left lingual gyrus were activated in the comparison of aesthetic appreciation of paintings versus photographic analogs. In conclusion, the present findings suggest a possibility of the existence of specific neural correlates associated with the aesthetic appreciation for paintings and that bilateral cuneus and the left lingual gyrus may be involved. PMID:25071508

  13. Analogy between gambling and measurement-based work extraction

    NASA Astrophysics Data System (ADS)

    Vinkler, Dror A.; Permuter, Haim H.; Merhav, Neri

    2016-04-01

    In information theory, one area of interest is gambling, where mutual information characterizes the maximal gain in wealth growth rate due to knowledge of side information; the betting strategy that achieves this maximum is named the Kelly strategy. In the field of physics, it was recently shown that mutual information can characterize the maximal amount of work that can be extracted from a single heat bath using measurement-based control protocols, i.e. using ‘information engines’. However, to the best of our knowledge, no relation between gambling and information engines has been presented before. In this paper, we briefly review the two concepts and then demonstrate an analogy between gambling, where bits are converted into wealth, and information engines, where bits representing measurements are converted into energy. From this analogy follows an extension of gambling to the continuous-valued case, which is shown to be useful for investments in currency exchange rates or in the stock market using options. Moreover, the analogy enables us to use well-known methods and results from one field to solve problems in the other. We present three such cases: maximum work extraction when the probability distributions governing the system and measurements are unknown, work extraction when some energy is lost in each cycle, e.g. due to friction, and an analysis of systems with memory. In all three cases, the analogy enables us to use known results in order to obtain new ones.

  14. Simulation of Hooke's Joint on the Analog Computer.

    ERIC Educational Resources Information Center

    Mitchell, Eugene E., Ed.

    1980-01-01

    A problem is presented that teaches the engineering student or practicing engineer the behavior of Hooke's joint, a widely used mechanism for transmitting rotary power in mechanical equipment. Also provided by this problem is an exercise in analog programing which utilizes nonlinear computer elements. (Author/CS)

  15. Graphene-on-semiconductor substrates for analog electronics

    DOEpatents

    Lagally, Max G.; Cavallo, Francesca; Rojas-Delgado, Richard

    2016-04-26

    Electrically conductive material structures, analog electronic devices incorporating the structures and methods for making the structures are provided. The structures include a layer of graphene on a semiconductor substrate. The graphene layer and the substrate are separated by an interfacial region that promotes transfer of charge carriers from the surface of the substrate to the graphene.

  16. Difference in brain activations during appreciating paintings and photographic analogs.

    PubMed

    Mizokami, Yoshinori; Terao, Takeshi; Hatano, Koji; Hoaki, Nobuhiko; Kohno, Kentaro; Araki, Yasuo; Kodama, Kensuke; Makino, Mayu; Izumi, Toshihiko; Shimomura, Tsuyoshi; Fujiki, Minoru; Kochiyama, Takanori

    2014-01-01

    Several studies have investigated neural correlates of aesthetic appreciation for paintings but to date the findings have been heterogeneous. This heterogeneity may be attributed to previous studies' measurement of aesthetic appreciation of not only the beauty of paintings but also the beauty of motifs of the paintings. In order to better elucidate the beauty of paintings, it seems necessary to compare aesthetic appreciation of paintings and photographic analogs which included corresponding real images. We prepared for famous painters' pictures and their photographic analogs which were set up to resemble each painting in order to investigate the hypothesis that there exist specific neural correlates associated with the aesthetic appreciation for paintings. Forty-four subjects participated in functional magnetic resonance study which required comparisons of aesthetic appreciation of paintings of still life and landscape versus photographic analogs including corresponding real images of still life and landscape. Bilateral cuneus and the left lingual gyrus were activated in the comparison of aesthetic appreciation of paintings versus photographic analogs. In conclusion, the present findings suggest a possibility of the existence of specific neural correlates associated with the aesthetic appreciation for paintings and that bilateral cuneus and the left lingual gyrus may be involved.

  17. Shake for Sigma, Pray for Pi: Classroom Orbital Overlap Analogies

    ERIC Educational Resources Information Center

    Dicks, Andrew P.

    2011-01-01

    An introductory organic classroom demonstration is discussed where analogies are made between common societal hand contact and covalent bond formation. A handshake signifies creation of a [sigma] bond ("head-on" orbital overlap), whereas the action of praying illustrates "sideways" overlap and generation of a [pi] bond. The nature of orbital and…

  18. Oscillations and Analogies: Thomas Young, MD, FRS, Genius.

    ERIC Educational Resources Information Center

    Martindale, Colin

    2001-01-01

    Thomas Young was a renowned genius in his time who did important work in many scientific disciplines. In today's specialized environment, scientists in each discipline do not appreciate his work. Despite his current obscurity, Young exemplifies traits found in a first-order genius (analogical thinking, high intelligence, hard work, wide interests,…

  19. Descartes highlands: Possible analogs around the Orientale Basin, part D

    NASA Technical Reports Server (NTRS)

    Carroll, A. H.

    1972-01-01

    Two possible analogs, although not entirely satisfactory, offer reasonable alternatives to the volcanic interpretation of the Descartes highlands. Reconsideration of this complex terrain, prompted by the preliminary results of the Apollo 16 mission, will lead to the revision of some theories on lunar volcanism and also to a better understanding of the landforms caused by the formation of multi-ring basins.

  20. Inherently Analog Quantity Representations in Olive Baboons (Papio anubis).

    PubMed

    Barnard, Allison M; Hughes, Kelly D; Gerhardt, Regina R; Divincenti, Louis; Bovee, Jenna M; Cantlon, Jessica F

    2013-01-01

    Strong evidence indicates that non-human primates possess a numerical representation system, but the inherent nature of that system is still debated. Two cognitive mechanisms have been proposed to account for non-human primate numerical performance: (1) a discrete object-file system limited to quantities <4, and (2) an analog system which represents quantities comparatively but is limited by the ratio between two quantities. To test the underlying nature of non-human primate quantification, we asked eight experiment-naive olive baboons (Papio anubis) to discriminate between number pairs containing small (<4), large (>4), or span (small vs. large) numbers of food items presented simultaneously or sequentially. The prediction from the object-file hypothesis is that baboons will only accurately choose the larger quantity in small pairs, but not large or span pairs. Conversely, the analog system predicts that baboons will be successful with all numbers, and that success will be dependent on numerical ratio. We found that baboons successfully discriminated all pair types at above chance levels. In addition, performance significantly correlated with the ratio between the numerical values. Although performance was better for simultaneous trials than sequential trials, evidence favoring analog numerical representation emerged from both conditions, and was present even in the first exposure to number pairs. Together, these data favor the interpretation that a single, coherent analog representation system underlies spontaneous quantitative abilities in primates.

  1. Analog Film Images...Back-Up Digital Technology.

    ERIC Educational Resources Information Center

    Brunner, Alex

    1999-01-01

    Examines the role of microfilm in storing information to eliminate digital obsolescence. Discusses the benefits of digital-to-analog microfilm systems; changes in conventional microfilm technology; and the advantages of true hybrid imaging systems that allow retrieval of images from document microfilm, digitally created microfilm or paper scanners…

  2. Analog Video Authentication and Seal Verification Equipment Development

    SciTech Connect

    Gregory Lancaster

    2012-09-01

    Under contract to the US Department of Energy in support of arms control treaty verification activities, the Savannah River National Laboratory in conjunction with the Pacific Northwest National Laboratory, the Idaho National Laboratory and Milagro Consulting, LLC developed equipment for use within a chain of custody regime. This paper discussed two specific devices, the Authentication Through the Lens (ATL) analog video authentication system and a photographic multi-seal reader. Both of these devices have been demonstrated in a field trial, and the experience gained throughout will also be discussed. Typically, cryptographic methods are used to prove the authenticity of digital images and video used in arms control chain of custody applications. However, in some applications analog cameras are used. Since cryptographic authentication methods will not work on analog video streams, a simple method of authenticating analog video was developed and tested. A photographic multi-seal reader was developed to image different types of visual unique identifiers for use in chain of custody and authentication activities. This seal reader is unique in its ability to image various types of seals including the Cobra Seal, Reflective Particle Tags, and adhesive seals. Flicker comparison is used to compare before and after images collected with the seal reader in order to detect tampering and verify the integrity of the seal.

  3. Assessing the Impact of Bridging Analogies in Mechanics

    ERIC Educational Resources Information Center

    Yilmaz, Serkan; Eryilmaz, Ali; Geban, Omer

    2006-01-01

    The effects of bridging analogies teaching strategy and gender on Turkish high school students' misconceptions in mechanics were investigated. After a pilot study with 67 students in a nearby high school, the researchers' administered the revised Mechanics Misconception Test to 119 high school students as a pretest. Students in the experimental…

  4. Cognitive Transfer of Computer Programming Skills and Analogous Problem Solving.

    ERIC Educational Resources Information Center

    Jang, Younghee

    This study investigated the cognitive benefits of learning how to program by determining the degree of cognitive transfer of programming skills at a construct level to solving analogous problems in other domains. Subjects, who were students enrolled in four sections of the beginning Pascal programming course and two sections of a calculus course,…

  5. Mental Arithmetic Activates Analogic Representations of Internally Generated Sums

    ERIC Educational Resources Information Center

    Kallai, Arava Y.; Schunn, Christian D.; Fiez, Julie A.

    2012-01-01

    The internal representation of numbers generated during calculation has received little attention. Much of the mathematics learning literature focuses on symbolic retrieval of math facts; in contrast, we critically test the hypothesis that internally generated numbers are represented analogically, using an approximate number system. In an fMRI…

  6. Linearity optimization in a class of analog phase modulators

    NASA Technical Reports Server (NTRS)

    Hearn, C. P.

    1985-01-01

    This paper examines the ultimate modulating linearity attainable with a phase modulation technique based on the linear addition of quadrature phase carrier signals which have been multiplied by precisely defined nonlinear transformations of the modulating signal. Optimum gain coefficients are derived and plotted to permit implementation of analog phase modulators capable of exceptionally good linearity of phase deviations as large as 5 radians.

  7. ON THE FREQUENCY OF POTENTIAL VENUS ANALOGS FROM KEPLER DATA

    SciTech Connect

    Kane, Stephen R.; Kopparapu, Ravi Kumar; Domagal-Goldman, Shawn D.

    2014-10-10

    The field of exoplanetary science has seen a dramatic improvement in sensitivity to terrestrial planets over recent years. Such discoveries have been a key feature of results from the Kepler mission which utilizes the transit method to determine the size of the planet. These discoveries have resulted in a corresponding interest in the topic of the Habitable Zone and the search for potential Earth analogs. Within the solar system, there is a clear dichotomy between Venus and Earth in terms of atmospheric evolution, likely the result of the large difference (approximately a factor of two) in incident flux from the Sun. Since Venus is 95% of the Earth's radius in size, it is impossible to distinguish between these two planets based only on size. In this Letter we discuss planetary insolation in the context of atmospheric erosion and runaway greenhouse limits for planets similar to Venus. We define a ''Venus Zone'' in which the planet is more likely to be a Venus analog rather than an Earth analog. We identify 43 potential Venus analogs with an occurrence rate (η{sub ♀}) of 0.32{sub −0.07}{sup +0.05} and 0.45{sub −0.09}{sup +0.06} for M dwarfs and GK dwarfs, respectively.

  8. Disaccharide conformational maps: adiabaticity in analogs with variable ring shapes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Relaxed MM3 potential energy surfaces (conformational maps) were calculated for analogs of the three trehaloses, maltose, cellobiose and galabiose based on 2-methyltetrahydropyran. Starting structures included not only 4C1 (sugar nomenclature) geometries, but also combinations with 1C4 conformers, a...

  9. Synthesis and biological activity of nifuroxazide and analogs.

    PubMed

    Tavares, L C; Penna, T C; Amaral, A T

    1997-03-01

    Nifuroxazide and thirteen analogs were synthesized from substituted benzoic acids and minimal inhibitory concentrations were determined using the serial dilution tests, in three sequential steps. Nifuroxazide and chloramphenicol were used as reference standards. The tests were performed in TSB against the standard bacterial strain of Staphylococcus aureus ATCC 25923. PMID:9164164

  10. 50. DETAIL OF TYPICAL PANELS IN ANALOG RECORD BAY. LEFT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    50. DETAIL OF TYPICAL PANELS IN ANALOG RECORD BAY. LEFT PANEL CONTAINS OSCILLOGRAPH AND CONTROLS. RIGHT PANEL CONTAINS CATHODE RAY TUBE AND INK-TYPE CHART RECORDER. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Operations Building, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  11. Synthesis and biological evaluation of novel peripherally active morphiceptin analogs.

    PubMed

    Gach, Katarzyna; do-Rego, Jean Claude; Fichna, Jakub; Storr, Martin; Delbro, Dick; Toth, Geza; Janecka, Anna

    2010-08-01

    Morphiceptin (Tyr-Pro-Phe-Pro-NH(2)), a tetrapeptide present in the enzymatic digest of bovine beta-casein, is a selective ligand of the mu-opioid receptor. In the present study, we describe the synthesis of a series of novel morphiceptin analogs modified in positions 1-3. Two of the obtained analogs, [Dmt(1), D-Ala(2), D-1-Nal(3)]morphiceptin and [Dmt(1), D-NMeAla(2), D-1-Nal(3)]morphiceptin (Dmt-2',6'-dimethyltyrosine and d-1-Nal-3-(1-naphthyl)-D-alanine)) displayed very high mu-receptor affinity, resistance to enzymatic degradation, and remarkable supraspinally mediated analgesia, as shown in the hot-plate test after intracerebroventricular but not intravenous administration, which indicated that they could not cross the blood-brain barrier. Therefore, these two analogs were further tested in vitro and in vivo towards their possible peripheral analgesic activity and inhibitory effect on gastrointestinal (GI) motility. We report that both peptides showed strong antinociceptive effect in the writhing test after intraperitoneal administration, inhibited smooth muscle contractility in vitro and GI motility in vivo. Taken together, these findings indicate that the novel morphiceptin analogs which induce peripheral, but not central antinociception, inhibit GI transit, and possess exceptional metabolic stability, may provide an interesting approach to the development of peripherally restricted agents for the treatment of GI motility disorders, such as diarrhea or diarrhea-predominant irritable bowel syndrome.

  12. Configurable analog-digital conversion using the neural engineering framework

    PubMed Central

    Mayr, Christian G.; Partzsch, Johannes; Noack, Marko; Schüffny, Rene

    2014-01-01

    Efficient Analog-Digital Converters (ADC) are one of the mainstays of mixed-signal integrated circuit design. Besides the conventional ADCs used in mainstream ICs, there have been various attempts in the past to utilize neuromorphic networks to accomplish an efficient crossing between analog and digital domains, i.e., to build neurally inspired ADCs. Generally, these have suffered from the same problems as conventional ADCs, that is they require high-precision, handcrafted analog circuits and are thus not technology portable. In this paper, we present an ADC based on the Neural Engineering Framework (NEF). It carries out a large fraction of the overall ADC process in the digital domain, i.e., it is easily portable across technologies. The analog-digital conversion takes full advantage of the high degree of parallelism inherent in neuromorphic networks, making for a very scalable ADC. In addition, it has a number of features not commonly found in conventional ADCs, such as a runtime reconfigurability of the ADC sampling rate, resolution and transfer characteristic. PMID:25100933

  13. Discovering Hidden Analogies in an Online Humanities Database.

    ERIC Educational Resources Information Center

    Cory, Kenneth A.

    1999-01-01

    Drawing upon an efficacious method for discovering previously unknown causes of medical syndromes and searching in the Humanities Index, an illuminating new humanities analogy between the epistemological ideas of Robert Frost and the ancient Greek philosopher Carneades was found by constructing a search statement in which proper names were coupled…

  14. 49. VIEW OF ANALOG RECORD BAY OF TELEMETRY CHECKOUT SYSTEM. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    49. VIEW OF ANALOG RECORD BAY OF TELEMETRY CHECKOUT SYSTEM. BAY LOCATED CENTRALLY IN TELEMETRY ROOM (ROOM 106) MIDWAY BETWEEN EAST AND WEST WALLS. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Operations Building, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  15. On a q-analog of a Sahi result

    SciTech Connect

    Bershtein, Olga

    2007-04-15

    We obtain a q-analog of a well-known Sahi result on the joint spectrum of S(GL{sub n}xGL{sub n})-invariant differential operators with polynomial coefficients on the vector space of complex nxn matrices.

  16. An analog model for quantum lightcone fluctuations in nonlinear optics

    SciTech Connect

    Ford, L.H.; De Lorenci, V.A.; Menezes, G.; Svaiter, N.F.

    2013-02-15

    We propose an analog model for quantum gravity effects using nonlinear dielectrics. Fluctuations of the spacetime lightcone are expected in quantum gravity, leading to variations in the flight times of pulses. This effect can also arise in a nonlinear material. We propose a model in which fluctuations of a background electric field, such as that produced by a squeezed photon state, can cause fluctuations in the effective lightcone for probe pulses. This leads to a variation in flight times analogous to that in quantum gravity. We make some numerical estimates which suggest that the effect might be large enough to be observable. - Highlights: Black-Right-Pointing-Pointer Lightcone fluctuations, quantum fluctuations of the effective speed of light, are a feature of quantum gravity. Black-Right-Pointing-Pointer Nonlinear dielectrics have a variable speed of light, analogous to the effects of gravity. Black-Right-Pointing-Pointer Fluctuating electric fields create the effect of lightcone fluctuations in a nonlinear material. Black-Right-Pointing-Pointer We propose to use squeezed light in a nonlinear material as an analog model of lightcone fluctuations. Black-Right-Pointing-Pointer Variation in the speed of propagation of pulses is the observational signature of lightcone fluctuations.

  17. Nearby Young Solar Analogs: I. Catalog and Stellar Characteristics

    NASA Technical Reports Server (NTRS)

    Gaidos, E. J.

    1998-01-01

    We present a catalog of 38 young solar analogs within 25 pc, stars which are uniquely well-suited for observations of thier circumstellar environments to improve our understanding of conditions within the Solar System during the Hadean/early Archean eons (prior to 3.8 Ga).

  18. Have You Been Flossing? An Analogy for Educational Program Assessment

    ERIC Educational Resources Information Center

    Jorgensen, Marcus

    2008-01-01

    In the author's position as director of institutional effectiveness and currently as a department assessment chair, he relates that he has found it useful to use an analogy between flossing one's teeth and instituting assessment. There are more similarities between flossing and assessment than one might imagine. In this article, the author…

  19. Metaphors & Analogies: Power Tools for Teaching Any Subject

    ERIC Educational Resources Information Center

    Wormeli, Rick

    2009-01-01

    Metaphors and analogies are more than figurative language suitable only for English classes and standardized test questions. They are "power tools" that can electrify learning in every subject and at all grade levels. Metaphors show students how to make connections between the concrete and the abstract, prior knowledge and unfamiliar concepts, and…

  20. Basalt: Biologic Analog Science Associated with Lava Terrains

    NASA Astrophysics Data System (ADS)

    Lim, D. S. S.; Abercromby, A.; Kobs-Nawotniak, S. E.; Kobayashi, L.; Hughes, S. S.; Chappell, S.; Bramall, N. E.; Deans, M. C.; Heldmann, J. L.; Downs, M.; Cockell, C. S.; Stevens, A. H.; Caldwell, B.; Hoffman, J.; Vadhavk, N.; Marquez, J.; Miller, M.; Squyres, S. W.; Lees, D. S.; Fong, T.; Cohen, T.; Smith, T.; Lee, G.; Frank, J.; Colaprete, A.

    2015-12-01

    This presentation will provide an overview of the BASALT (Biologic Analog Science Associated with Lava Terrains) program. BASALT research addresses Science, Science Operations, and Technology. Specifically, BASALT is focused on the investigation of terrestrial volcanic terrains and their habitability as analog environments for early and present-day Mars. Our scientific fieldwork is conducted under simulated Mars mission constraints to evaluate strategically selected concepts of operations (ConOps) and capabilities with respect to their anticipated value for the joint human and robotic exploration of Mars. a) Science: The BASALT science program is focused on understanding habitability conditions of early and present-day Mars in two relevant Mars-analog locations (the Southwest Rift Zone (SWRZ) and the East Rift Zone (ERZ) flows on the Big Island of Hawai'i and the eastern Snake River Plain (ESRP) in Idaho) to characterize and compare the physical and geochemical conditions of life in these environments and to learn how to seek, identify, and characterize life and life-related chemistry in basaltic environments representing these two epochs of martian history. b) Science Operations: The BASALT team will conduct real (non-simulated) biological and geological science at two high-fidelity Mars analogs, all within simulated Mars mission conditions (including communication latencies and bandwidth constraints) that are based on current architectural assumptions for Mars exploration missions. We will identify which human-robotic ConOps and supporting capabilities enable science return and discovery. c) Technology: BASALT will incorporate and evaluate technologies in to our field operations that are directly relevant to conducting the scientific investigations regarding life and life-related chemistry in Mars-analogous terrestrial environments. BASALT technologies include the use of mobile science platforms, extravehicular informatics, display technologies, communication