Chiral Type II Orientifold Constructions as M Theory on G_2 holonomy spaces

We summarize some recent progress in constructing four-dimensional supersymmetric chiral models from Type II orientifolds. We present the construction a supersymmetric Standard-like Model and a supersymmetric GUT model to illustrate the new features of this approach and its connection to M theory on compact, singular G_2 holonomy spaces. The Standard-like model presented is the first example of a three-family supersymmetic orientifold model with the Standard Model as part of the gauge structure. We also discuss the connection of how chiral fermions arise in this class of models with recent results of M theory compactified on G_2 holonomy spaces.Comment: 10 pages SUSY '01 Proceedings Contributio

Hierarchies from D-brane instantons in globally defined Calabi-Yau Orientifolds

We construct the first globally consistent semi-realistic Type I string vacua on an elliptically fibered manifold where the zero modes of the Euclidean D1-instanton sector allow for the generation of non-perturbative Majorana masses of an intermediate scale. In another class of global models, a D1-brane instanton can generate a Polonyi-type superpotential breaking supersymmetry at an exponentially suppressed scale.Comment: 4 pages, 4 tables, uses revtex; v2: Discussion of instanton curves improved, typos fixed, references added; v3: version published in PR

Are the Graduate Students of English Language Teaching Program Ready to Teach the Undergraduates?

According to the curriculum of the Graduate Program, Universitas Negeri Malang, the graduate (S2) students of the English Language Teaching program have to take teaching practicum in their third semester, where they have to teach the undergraduate students. In the past, they could choose and apply for the subjects that they wanted to teach, either skill or content courses. Since the academic year 2012, however, the practice has changed. The students no longer have to teach at the undergraduate program; instead they only have to do Peer Teaching with their classmates. In the past, graduate students were mostly teachers or lecturers of English; while currently they enrol at the Graduate Program straight after graduating from their undergraduate (S1) degree. Some of them are teachers of private courses, some are junior lecturers with 1-5 years\u27 experience, while the rest are fresh graduates who have nevertaught. Questions then arise: are these students ready to teach the undergraduates? What difficulties do they have in the teaching practicum? What do they hope to get from the course? This paper presents the results of my mini research concerning the readiness of the students to do the teaching practicum, and their hopes and expectations regarding the conduct of the Teaching Practicum Course. Data were taken from observations and questionnaire to 35 students from two classes of the 2014 cohort. Most of them stated that they still needed further lessons, especially in Classroom management and materials selection to equip them. This is in line with the writer\u27s observations which show that many of their practicum are still teacher-centered, and there is some apparent difficulty in time management. Some suggestions on improving the curriculum for the graduate program are provided

Non-perturbative Yukawa Couplings from String Instantons

Non-perturbative D-brane instantons can generate perturbatively absent though phenomenologically relevant couplings for Type II orientifold compactifications with D-branes. We discuss the generation of the perturbatively vanishing SU(5) GUT Yukawa coupling of type 10 10 5_H. Moreover, for a simple globally consistent intersecting D6-brane model, we discuss the generation of mass terms for matter fields. This can serve as a mechanism for decoupling exotic matter.Comment: 4 pages, 2 tables, 2 figure

General N = 1 Supersymmetric Flux Vacua of (Massive) Type IIA String Theory

We derive conditions for the existence of four-dimensional \N=1 supersymmetric flux vacua of massive type IIA string theory with general supergravity fluxes turned on. For an SU(3) singlet Killing spinor, we show that such flux vacua exist only when the internal geometry is nearly-K\"ahler. The geometry is not warped, all the allowed fluxes are proportional to the mass parameter and the dilaton is fixed by a ratio of (quantized) fluxes. The four-dimensional cosmological constant, while negative, becomes small in the vacuum with the weak string coupling.Comment: 4 page

Vocal production learning in mammals revisited

Vocal production learning, the ability to modify the structure of vocalizations as a result of hearing those of others, has been studied extensively in birds but less attention has been given to its occurrence in mammals. We summarize the available evidence for vocal learning in mammals from the last 25 years, updating earlier reviews on the subject. The clearest evidence comes from cetaceans, pinnipeds, elephants and bats where species have been found to copy artificial or human language sounds, or match acoustic models of different sound types. Vocal convergence, in which parameter adjustments within one sound type result in similarities between individuals, occurs in a wider range of mammalian orders with additional evidence from primates, mole-rats, goats and mice. Currently, the underlying mechanisms for convergence are unclear with vocal production learning but also usage learning or matching physiological states being possible explanations. For experimental studies, we highlight the importance of quantitative comparisons of seemingly learned sounds with vocal repertoires before learning started or with species repertoires to confirm novelty. Further studies on the mammalian orders presented here as well as others are needed to explore learning skills and limitations in greater detail.Publisher PDFPeer reviewe

Clinical review: The role of biomarkers in the diagnosis and management of community-acquired pneumonia

In patients with community-acquired pneumonia, traditional criteria of infection based on clinical signs and symptoms, clinical scoring systems, and general inflammatory indicators (for example, leukocytosis, fever, C-reactive protein and blood cultures) are often of limited clinical value and remain an unreliable guide to etiology, optimal therapy and prognosis. Procalcitonin is superior to other commonly used markers in its specificity for bacterial infection (allowing alternative diagnoses to be excluded), as an indicator of disease severity and risk of death, and mainly as a guide to the necessity for antibiotic therapy. It can therefore be viewed as a diagnostic, prognostic, and perhaps even theragnostic test. It more closely matches the criteria for usefulness than other candidate biomarkers such as C-reactive protein, which is rather a nonspecific marker of acute phase inflammation, and proinflammatory cytokines such as plasma IL-6 levels that are highly variable, cumbersome to measure, and lack specificity for systemic infection. Elevated levels of pro-adrenomedullin, copeptin (which is produced in equimolar amounts to vasopressin), natriuretic peptides and cortisol are significantly related to mortality in community-acquired pneumonia, as are other prohormones such as pro-atrial natriuretic peptide, coagulation markers, and other combinations of inflammatory cytokine profiles. However, all biomarkers have weaknesses as well as strengths. None should be used on its own; and none is anything more than an aid in the exercise of clinical judgment based upon a synthesis of available clinical, physiologic and laboratory features in each patient

The Turncoat Phenomenon: Role Conceptions of PR Practitioners Who Used To Be Journalists

For a long time, Dutch parliamentary journalists have shown an interest in migrating to the “other side” and becoming political PR professionals or spokespersons. The Dutch term used by journalists for colleagues who make this switch is “overloper” (turncoat). It is a term with a clear negative connotation, which says a lot about how journalists view the field of public relations. The relationship between journalism and public relati

Entropy of Non-Extreme Charged Rotating Black Holes in String Theory

We give the explicit expression for four-dimensional rotating charged black hole solutions of N=4 (or N=8) superstring vacua, parameterized by the ADM mass, four charges (two electric and two magnetic charges, each arising from a different U(1) gauge factors), and the angular momentum (as well as the asymptotic values of four toroidal moduli of two-torus and the dilaton-axion field). The explicit form of the thermodynamic entropy is parameterized in a suggestive way as a sum of the product of the `left-moving' and the `right-moving' terms, which may have an interpretation in terms of the microscopic degrees of freedom of the corresponding D-brane configuration. We also give an analogous parameterization of the thermodynamic entropy for the recently obtained five-dimensional rotating charged black holes parameterized by the ADM mass, three U(1) charges and two rotational parameters (as well as the asymptotic values of one toroidal modulus and the dilaton).Comment: 14 pages, uses RevTex, the revised version with minor corrections to appear in Phys. Rev.

Black Holes and U-Duality

We find the general charged rotating black hole solutions of the maximal supergravities in dimensions $4\le D\le 9$ arising from toroidally compactified Type II string or M-theories. In each dimension, these are obtained by acting on a generating solution with classical duality symmetries. In D=4, D=5 and $6\le D \le 9$ the generating solution is specified by the ADM mass, $[{D-1}/2]$-angular momentum components and five, three and two charges, respectively. We discuss the BPS-saturated (static) black holes and derive the U-duality invariant form of the area of the horizon. We also comment on the U-duality invariant form of the BPS mass formulae.Comment: Minor corrections. Version to appear in Nuclear Physics