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While Luria and Delbrück’s seminal work has found its way to some college biology textbooks, it is now largely absent from those in mathematics. This is a significant omission, and we consider it a missed opportunity to present a celebrated conceptual model that provides an authentic and, in many ways, intuitive example of the quantifiable nature of stochasticity. We argue that it is an important topic that could enrich the educational literature in mathematics, from the introductory to advanced levels, opening many doors to undergraduate research. The paper has two main parts. First, we present in detail the mathematical theory behind the Luria–Delbrück model and make suggestions for further readings from the literature. We also give ideas for inclusion in various mathematics courses and for projects that can be used in regular courses, independent projects, or as starting points for student research. Second, we briefly review available hands-on activities as pedagogical ways to facilitate problem posing, problem-based learning, and investigative case-based learning and to expose students to experiments leading to Poisson distributions. These help students with even limited mathematics backgrounds understand the significance of Luria–Delbrück’s work for determining mutation rates and its impact on many fields, including cancer chemotherapy, antibiotic resistance, radiation, and environmental screening for mutagens and teratogens.

While Luria and Delbrück’s seminal work has found its way to some college biology textbooks, it is now largely absent from those in mathematics. This is a significant omission, and we consider it a missed opportunity to present a celebrated conceptual model that provides an authentic and, in many ways, intuitive example of the quantifiable nature of stochasticity. We argue that it is an important topic that could enrich the educational literature in mathematics, from the introductory to advanced levels, opening many doors to undergraduate research. The paper has two main parts. First, we present in detail the mathematical theory behind the Luria–Delbrück model and make suggestions for further readings from the literature. We also give ideas for inclusion in various mathematics courses and for projects that can be used in regular courses, independent projects, or as starting points for student research. Second, we briefly review available hands-on activities as pedagogical ways to facilitate problem posing, problem-based learning, and investigative case-based learning and to expose students to experiments leading to Poisson distributions. These help students with even limited mathematics backgrounds understand the significance of Luria–Delbrück’s work for determining mutation rates and its impact on many fields, including cancer chemotherapy, antibiotic resistance, radiation, and environmental screening for mutagens and teratogens.

Editado por Jiménez-López, José Carlos (CSIC)

An approximately 10-year-old, female Congo African grey parrot ( Psittacus erithacus erithacus) developed progressive, unilateral exophthalmos and buphthalmos. Survey radiographs revealed a large, coelomic, soft tissue mass, which was confirmed on computed tomography scan. Aspirates of both the contents of the buphthalmic globe and coelomic mass were consistent with Cryptococcus species. Initial results were later confirmed with serum antigen latex agglutination and polymerase chain reaction testing, and the organism was then identified as Cryptococcus neoformans with DNA sequencing. During the course of 1 year, the bird was treated with combinations of oral terbinafine, fluconazole, and flucytosine, as well as intraocular amphotericin B. The coelomic mass dramatically decreased in size during the course of treatment, but the globe continued to enlarge. The bird died after exhibiting ataxia and seizures approximately 13 months after initial diagnosis, and necropsy confirmed colonization of the cerebrum and meninges with Cryptococcus. Cryptococcus remains a rare fungal disease of birds that is often refractory to treatment.

Human activity detection becomes important aspect in zone monitoring and protection systems in military scenarios. This work is focused on comparing the types of detectors and thereby suggesting the best possible detector for multiple sample signals of footsteps. Multiple features were extracted and analysed. A Log-Likelihood Ratio Test detector has been designed, assuming that the DFT Coefficients follow either a Laplacian or a Gaussian distribution. Among Laplacian based and Gaussian based detectors, Laplacian has proved to perform better in samples with lower SNR values, while both Laplacian and Gaussian detectors perform equally well in the higher SNR signals.

We investigate the relationship between the sigma-field and the infinitesimal or germ sigma-field., 2000 Mathematics Subject Classification: 60G15, 60G60; secondary 31B15, 31B25, 60H15

Background The missile injuries of the cranium and brain in the modern era have shifted from soldiers to the civilians and from the battle grounds to the populated zones due to increase in the terrorist and military strikes. The management of the victims depends on the resuscitation at the site of injury and the distance and transportation to the tertiary care centre. This article presents the details of the missile injuries to the brain, the third-world problems and the management. Material and methods A retrospective analysis of 3794 craniocerebral missile injuries, managed by the Department of Neurosurgery at Sher-I-Kashmir Institute of Medical Sciences (SKIMS) Kashmir, India, over a period of more than 21 years from September 1988 to September 2009. Patients were triaged in emergency CT-room, resuscitated and operated. Statistical software programme SPSS 11.5 was used to derive the numerical significance. Results Revealed an overall mortality of 87.69% (3327 out of 3794). Most of the deaths 79.14% (2633 out of 3327) occurred within 30 minutes of the patient’s arrival to the hospital and only 694 patients lived beyond one hour of arrival. Conclusion Presently the quantum of outcome i.e, survival and good recovery in craniocerebral missile injuries appears a meager heap compared to the huge amount of death and disability. And the situation will continue to be so unless tertiary care hospitals are set up within and around the armed and conflict zones, war torn areas and battle fields, rather than risking transportation, time of resuscitation, intervention and the results.Key words: Craniocerebral, Kashmir, Missile Injuries, Outcome.

Department of Chemistry, University of Jammu, Jammu-180 006, Jammu & Kashmir, India E-mail : hnsheikh@rediffmail.com Manuscript received 21 August 2006, revised 15 June 2007, accepted 18 June 2007 Synthesis and characterization of nitrosylpseudohalochromium(I) complexes of the composition, [Cr(NO)X2L.H2O], where X = NCS- or NCO- and L = morpholinomethyl urea (MMU), morpholinomethyl thiourea (MMTU), piperidinomethyl urea (PMU) or piperidinomethyl thiourea (PMTU) is presented. These complexes have been prepared by treatment of potassium chromate with potassium thiocyanate/potassium cyanate and hydroxylamine hydrochloride followed by the addition of ligand (L). The complexes have been characterized by usual procedure.

Objective To determine the demand and preferences of infertility patients for sex selection and the method and sex they would choose, and to investigate the relationship between these choices and their demographic and socioeconomic characteristics. Design Cross-sectional survey. Setting University hospital-based fertility center. Patient(s) One thousand five hundred consecutive women who presented for infertility care. Intervention(s) None. Main outcome measure(s) Self-report questionnaire assessing the demand and preferences for sex selection. Result(s) Of respondents, 40.8% wanted to select the sex of their next child for no added cost. Of these patients, 45.9% had no living children and 48.4% had children all of one sex. After adjustment for observed predictors of gender preference, we found a significant preference for a female child among women who were older, not religious, willing to pay for sex selection, had more living children, had only sons, or had a diagnosis of male infertility. Nulliparous women did not significantly prefer one sex over the other. Among parous women, those with only daughters significantly desired to select a male child, whereas those with sons significantly desired to select a female child. In terms of the method of sex selection, 55.0%, 41.0%, and 4.0% of the patients would use sperm separation, preimplantation genetic diagnosis, or neither method, respectively. Conclusion(s) There is significant demand among infertility patients for preimplantation sex selection, with a significant portion of this demand coming from patients who do not have any children or have children all of one sex.

The interleukin 1 (IL-1) receptor from mouse EL-4 thymoma cells was purified to homogeneity by a method which utilized ligand affinity chromatography and classical chromatographic techniques. After solubilization of the receptor from intact cells with the zwitterionic detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate, the IL-1 binding activity was purified greater than 23,000-fold. Analysis of the purified protein by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoblot, and ligand blot demonstrated that a single protein of molecular mass of approximately 80 kDa is the IL-1 binding polypeptide. The purified protein bound IL-1 with a dissociation constant of approximately 1.1 X 10(-10) M, which is indistinguishable from the affinity of the cell-bound receptor. The amino acid composition of this protein is strikingly similar to the composition deduced from the sequence of a cDNA coding for an IL-1 receptor from EL-4 cells. Protein sequence analysis of Staphylococcus aureus V-8 protease-derived peptides yields data consistent with the sequence proposed from cloned cDNA. These studies have demonstrated that the high affinity IL-1 receptor on EL-4 cells is the 80-kDa protein.

This article 'Performance of Anther-Derived Rice Lines' appeared in the International Rice Research Newsletter series, created by the International Rice Research Institute (IRRI). The primary objective of this publication was to expedite communication among scientists concerned with the development of improved technology for rice and for rice based cropping systems. This publication will report what scientists are doing to increase the production of rice in as much as this crop feeds the most densely populated and land scarce nations in the world.

This article 'Anther Culture of Basmati 370 At IRRI. A. Gamma Ray-Induced Green Plant Regeneration' appeared in the International Rice Research Newsletter series, created by the International Rice Research Institute (IRRI). The primary objective of this publication was to expedite communication among scientists concerned with the development of improved technology for rice and for rice based cropping systems. This publication will report what scientists are doing to increase the production of rice in as much as this crop feeds the most densely populated and land scarce nations in the world.

This article 'Anther Culture of Basmati 370 At IRRI. B. Effect of Glucose in Anther Culture of Irradiated Basmati 370' appeared in the International Rice Research Newsletter series, created by the International Rice Research Institute (IRRI). The primary objective of this publication was to expedite communication among scientists concerned with the development of improved technology for rice and for rice based cropping systems. This publication will report what scientists are doing to increase the production of rice in as much as this crop feeds the most densely populated and land scarce nations in the world.

This article 'A Simple Device for Mass Extraction of Rice Anthers' appeared in the International Rice Research Newsletter series, created by the International Rice Research Institute (IRRI). The primary objective of this publication was to expedite communication among scientists concerned with the development of improved technology for rice and for rice based cropping systems. This publication will report what scientists are doing to increase the production of rice in as much as this crop feeds the most densely populated and land scarce nations in the world.

This article 'Improved Medium for Efficient Anther Culture of Some Indica Rice Hybrids' appeared in the International Rice Research Newsletter series, created by the International Rice Research Institute (IRRI). The primary objective of this publication was to expedite communication among scientists concerned with the development of improved technology for rice and for rice based cropping systems. This publication will report what scientists are doing to increase the production of rice in as much as this crop feeds the most densely populated and land scarce nations in the world.